User Manual - SF2-CCRsf2-ccr.co.uk/assets/downloads/SF2-user-Manual-Eng2.pdf · The operating temperature for the SF2 lies between a minimum of 4° Celsius and a maximum of 34° Celsius

1

User Manual

2

SF2

Electronically controlled

Closed circuit rebreather

User Manual

Version 1.3

January 2011

dive2gether.net Tauchsport GmbH

Siemensstraße 10

41363 Jüchen (Hochneukirch)

Germany

Text, Photos and Numbers Copyright © 2011

with SF2

No part of this book is supposed to be reproduced or transmitted in any way, neither

electronically nor mechanically including copying, recording or saving without written

permission of an authorized representative of dive2gether.

Danger: The SF2 is a fully electronic closed circuit rebreather

whose functions are significantly different from a traditional open

circuit diving system. Do not use the SF2 without proper

professional instruction by an authorised SF2 Instructor and

without proper and complete knowledge of the contents of this

manual.

Careless use of the SF2 can lead to unconsciousness due to a lack

of oxygen in any environment without any prior warning signs.

Careless use of the SF2 in depths underwater exceeding 6 MSW

(meters sea water) [20 FSW (feet sea water)] can lead to

unconsciousness without any prior warning signs. Both situations

can cause severe injuries or death. The SF2 is equipped with a

sophisticated electronic control system which allows for a properly

trained user to avoid these situations. It is solely the responsibility

of user to monitor the displays of this system carefully when using

the SF2, and to have the knowledge of bailout procedures in case

of a problem.

3

Table of Contents Accordance with CE-Standards (page 5,6)

Aim of this User Manual (page 7)

Glossary of Terms (page 8, 9)

Chapter 1

Overview of the SF2 Head (page 10)

Upper Section (page 10)

Bottom Section and SS Frame (page 11)

Soda Lime Canister (page 11)

Automatic Diluent Gas Valve (page 11)

Manual Gas Feed Connection (page 11)

Counter lung Securing Plate (page 12)

ADV Activation Plunger (page 12)

Counter lung combined Water Trap (page 12)

Breathing Hoses (page 13)

Chapter 2

Assembling the SF2 Counter lung and combined Water Trap (page 14, 15)

Inserting Middle Section in Bottom Section and SS Frame (page 15)

Attaching the Upper Section (page 15)

Filling the Soda Lime Canister (page 16)

Inserting the Soda Lime Canister (page 17)

Soda Lime (page 18)

Battery Fitting (page19)

Oxygen Sensor Fitting (page 19, 20)

Head Cover Plate Assembly (page 20)

Attaching the Head (page20)

Overview of Breathing Hoses (page 20)

Breathing Hoses Leak Test (page 21,22)

Attaching Breathing Hoses (page 20)

Diluent and Oxygen Cylinders (page 23)

Tank Mounting (page 24)

Screwing on the First Stages(page 23,24)

Mounting the Tanks to the SF2 (page 24)

Attaching the Wing and Backplate (page 25)

Manual Adds (page 25)

Chapter 3 Electronics Shearwater Predator

Original Predator Manual (page 26)

4

Chapter 4

Care and Maintenance (page 76)

First Stage requirements (page 79)

Gas Cylinders and Filling Gas Cylinders (page 79)

Clearing and Equalizing the Mask (page 80)


Chapter 5

Pre-Dive Procedures

First Steps before Diving (page 79)

Soda Lime Canister (page 79)

Gas Cylinders (page 80)


Starting the Electronics (page 82)

Battery state (page 80)

Calibrating the Oxygen Sensors (page 81)

Negative Pressure Test (page 79)

Positive Pressure Test (page 80)

Bailout Gases (page 81)

Ready to Dive (page 83)

Chapter 6

Diving Procedures Monitoring Alarms (page 82)

Minimum Loop Volume (page 82)

Buoyancy Control (page 83)

Removing Water from the Breathing Hoses (page 83)

Performing Ascents (page 83)

Ending the Dive (page 83)

Safe Diving with the SF2 (page 84)

Post Dive Care (page 84)

Problem Solving (page 85)

Chapter 7

Care and Maintenance after the Dive

After Every Dive (page 86)

More Than One Dive Per Day (page 86)

After Every Full Day of Diving (page 86)

Disinfection (page 88)

Long-term Storing and Care (page 87)

Travelling with the SF2 (page 87)

5

Accordance with CE-Demands

In accordance with the European Standard EN14143, paragraph 8 we hereby supply the

following information:

8.1

This manual contains information which authorizes trained and qualified persons to assemble

and use the SF2 in a secure and safe way.

8.2

This manual was originally written in German.

8.3

The application of the SF2 is an autonomic recreational diving device. For dives with Air and

Trimix 10/70 gas. The SF2 is licensed for a maximum depth of 40 mtrs (130ft) with Air

Diluent or to 100mtrs (325ft) with Trimix 10/70 Diluent. The SF2 uses two gas supplies:

Trimix 10/70 or Air diluents and Oxygen; and those which are produced by the breathing gas

mixture mixed by the SF2. The use of the SF2 is limited to diving underwater only by

properly trained persons. Detailed instructions concerning the assembly of the SF2 including

descriptions of the single components, the special connection between the components as

well as the various safety elements are contained in this manual.

The user should be able to understand the risks and should also appreciate the risks associated

with the use of the SF2 and the use of this manual in conjunction with qualified SF2

instructor training prior to the diving. The operating temperature for the SF2 lies between a

minimum of 4° Celsius and a maximum of 34° Celsius. Using the device outside of these

limits can lead to malfunctions. The SF2 is intended for use on dives that require low to

moderate work performance. Although the SF2 is capable of standing up to high work

performances, this is not its intention. The SF2 is intended to supply a breathing gas mixture

with a partial pressure between 0.4 bar (0.35 bar minimum) and 1.3 bar (1.5 bar maximum).

Depending on the depth of the dive, the fraction of oxygen in the breathing gas should be

between 21% and 100%, nitrogen between 0% and 79% and helium between 0% and 70%

depending on Diluent used i.e Air or Trimix 10/70. Users have to monitor the displays,

gauges and alarm systems and react appropriately when the concentration of oxygen becomes

dangerous.

The SF2 requires the monitoring of an OLED display and, accordingly, should only be used

in waters with a minimum visibility of at least 30cm. The use of the SF2 under conditions

that do not allow monitoring of the OLED display presents an increased risk.

The SF2 includes oxygen at high pressure as one of its gas supplies and employs equipment

that has been specially cleaned and prepared for dealing with high pressure oxygen.

Accordingly, special care has to be applied when handling these gas mixtures, especially

when refilling the gas cylinders.

Adequate maintenance and cleanliness suitable for oxygen must thus be supplied for every

component that gets in touch with high pressure oxygen (e.g. oxygen breathing regulators and

connected pneumatic parts). Components which are exposed to high pressure oxygen have to

be maintained by qualified Service Center.

Not complying with these instructions can lead to an oxygen fire and serious injuries

including death.

The SF2 requires a proper assembly prior to diving and some important testing procedures

that have to be carried out by the diver. Details regarding these procedures are included in

this manual.

The use of the SF2 without complete testing of the system poses an increased risk on the

diver. Chapter 7 of this manual describes appropriate procedures after the dive as well as

requirements for long-term storing and care-taking of the SF2, including storage conditions,

6

durability of certain components and appropriate safety measures; moreover a maintenance

and inspection routine. Not complying with these procedures may lead to damage of the

components, which in turn may lead to malfunctions of the SF2.

8.4

The diluent gas cylinder of the SF2 is only to be filled with Trimix 10/70 or Air. The Helium

used must comply with category 6.0. The oxygen cylinder is only to be filled with medical or

diving grade oxygen of category 5.1. The SF2 must only be filled and used with Dräger

Divesorb Pro soda lime.

Only CE certified accessories and/or other personal safety equipment should be used with the

SF2. All other additions or changes by a third party are not covered by the intended use of

this device.

8.5

The soda lime duration time of this device is 60 minutes under the following conditions:

diving depth 50 meters, water temperature 4° Celsius. AMV 40 liters / minute

7

Aim of this Manual This manual is not intended to be a training manual or a substitute in any way for a proper

training provided by a SF2-certified Instructor or Facility. There are warning boxes

everywhere in this manual to draw your attention to important information. Three stages of

warning are highlight by the following coloured triangles:

Danger: Warning boxes with a red triangle contain highly critical

information on the diver's safety and well-being. Disregard of the

information in these boxes can lead to serious injuries or death.

Warning: Warning boxes with a yellow triangle contain vital information

that can have influence on the safety and/or the proper function of the SF2.

Important: Warning boxes with a blue triangle contain important

information on the appropriate care and maintenance of the SF2. These can

increase comfort and fun during the dive.

8

Explanation of Terms

SF2: Scuba Force 2

Breathing Hoses: Consists of the breathing hoses, the mouth piece and the connection threads.

Soda Lime: Lime that binds CO2 in a chemical process, and thus keeps the gas in the

circuit breathable.

ADV: Automatic Diluent Valve

Diluent is automatically supplied as soon as the volume in the circuit drops

below the inhaled volume. This can happen due to descending, clearing the

mask, metabolizing etc.

Bailout: Emergency procedure, exit from the circuit into an open system

CO2: Carbon dioxide

Diluent: A gas that is used for the dilution of oxygen to reduce PPO2

ECCR: Electronic Complete Closed Rebreather.

Counterlung: Bag to collect the exhaled gas and water

Hypercapnia: Where there is too much carbon dioxide (CO2) in the blood

Hypoxia: Condition in which the body or a region of the body is deprived of an adequate

Oxygen supply

Hyperoxia: It refers to excess oxygen in the lungs or other body tissues leading to oxygen

toxicity.

Controller: Is connected to the sensors and measures their single values, calculates the

average and compares it to the preset set point.

Calibrating: All oxygen cells must be calibrated with 100% oxygen

9

Soda Lime Canister: Container in which the soda lime is packed

PPO2: Partial Pressure Oxygen

Loop: Circuit consisting of lungs, counter lung, soda lime canister and breathing

hoses

Predator: Controller and dive computer in a display unit worn on the arm

Set point: A preset oxygen partial pressure which is monitored and maintained by the

controller

Oxygen Cells: Sensor cells that measure the oxygen level in the gas

Oxygen Solenoid: A valve that is set by the controller. Oxygen is used up while diving and

the sensors measure the oxygen level in the gas. When the oxygen

partial pressure drops below the preset set point, the controller

electronically opens the valve and oxygen flows into the loop

Over Pressure and Water Outlet Valve: The SF2 is equipped with an over pressure and water outlet valve, the water

outlet valve is used for clearing water from the loop; the over pressure valve

opens as soon as the pressure (gas volume) in the system increases e.g.

during ascents.

Water Trap: Saliva and moisture produced by the chemical process of CO2 binding but

also the moisture from the exhaled gas condenses in the rebreather. This

moist and warm gas condenses forming water droplets. To avoid

malfunction, the SF2 is build so that water and saliva produced by the above

reactions can move into the water trap and can be removed via the Water

Outlet Valve.

10

Chapter 1 SF2 Single Parts Overview

1. Head: Fig1

Ab2

Fig2

Fig3

Preparation: The SF2 rebreather is sealed with a radial O-ring in machined groove on the

head. It is necessary prior to every assembly to clean and slightly grease this O-ring with O2

grease.

Please notice that in order to do this; you should rub a small amount of O2 grease between

your first finger and thumb and then slide the O-ring through the two fingers. Doing so

ensures that the O-rings are evenly and glossily greased.

Avoid applying a thick layer of O2 grease to the O-ring since this can cause leakage. Before

the O-ring can be reinserted into the groove make sure that the groove is clean and free of

fibers and dirt. This is easily done by using Q-tips or cotton buds.

Fig4

Oxygen supply (9/16 18G Standard MD)

Oxygen Solenoid (Jaksa)

Oxygen line to exhale opening

3 oxygen cells and wiring (numbered1to3)

Battery compartment (1X PP9 battery)

Inhale opening

Cable Connection to Oxygen Solenoid

Exhale opening

Breathing Hose Connections

Cable with Predator

Cable with Fischer connector

2. Upper Section:

Connection between head and

middle section; contains the soda

lime canister (due to the

manufacturing process the pipe is

tapered and can only be assembled

in correct orientation.)

Head cover plate

protects the parts in the head

11

Fig5

Fig6

5. Middle Section:

Fig7

If the ADV is activated at every breath, could be due to a leak in the

counter lung, overpressure valve set too slack or poor diving techniques i.e

breathing out through the nose or poor fitting mask. This will result in an

increased consumption of breathing gas both for the oxygen and the diluent.

The consumption of breathing gas has to be constantly monitored.

Every diluent addition causes the PPO2 to drop which is instantaneously

recognized by the controller and oxygen added, if below setpoint, via the

oxygen solenoid, so that the PPO2 remains at the preset set point. ,

3. Bottom Section and SS Frame:

Mounting for oxygen and diluent

cylinders as well as for wing and

back plate provides a solid stand

and serves as a cover for the

counter lung.

4. Soda Lime Canister(Scrubber) Canister’s capacity is 2kg soda lime.

Strict attention must be paid that the

maximum breathing time of 3 hours for

the soda lime is not exceeded, especially

when using it for more than one dive.

Automatic Diluent Valve (ADV)

Diluent enters the loop via a second stage (Apeks

XTX20).

During the descent, gas is supplied via the ADV,

due to the volume being decreased with the higher

ambient pressure. Each time the volume in the

counter lung is compressed to lowest point the

plunger activates the ADV and diluent is added

Manual Gas Feed Connection

Manual gas feed connection allows the operator to manually add both oxygen

and diluents to the SF2. All connections are standard 3/8``UNF threads.

12

6. Counter lung Securing Plate: Fig8

Fig9

8. Counter lung and Water Trap: Fig10

Moisture is produced as a byproduct due to the chemical process of binding CO2 in the soda

lime but also due to respiration in the lungs. Because of the difference in temperature (inner

parts – outer parts) condensation occurs. This small amount of water could interfer with the

function of the rebreather.

The water trap collects the water which in turn falls into the counter lung, this water can be

removed through the overpressure valve in the bottom of counter lung, wherever it

originates from, by simply moving in an upright position manually adding diluent via

manual add and strongly exhaling which forces open the overpressure valve

The SF2 rebreather has the ability to cope with larger amounts of ingressed

water which can enter the rebreather due to loss of mouth piece, either entering

the water with an unclosed mouth piece or removing the mouth piece without

closing it. By moving in an upright position, the majority of the water will be

collected in the water trap and flows into the counter lung where it can be

removed by the method described this will be shown by your instructor on

your diver course.

Counter lung is attached to the securing

plate. Using 6 screws the securing plate

with the counter lung is screwed onto the

middle section. The counter lung also

serves as container for water from water

trap.

A bellow counter lung, reservoir for the

exhaled gas. Over pressure valve on the

bottom which can be adjusted to the diver’s

requirements also can be used to remove

water and saliva that has collected in the

loop. This is also used for flood recovery

which will explained by your instructor

7. Middle Section:

This is connection between Bottom and

Upper Sections. It houses ADV,manual

add inlet pipe and large O ring on the

upper side. On the bottom side is

attached a activation plunger for ADV.

This is enclosed inside counter lung

Activation plunger can be seen in fig9

with counter lung removed

13

Fig11

Warning: Never remove the mouth piece from your mouth in the open

position. Water will enter the SF2 and the rebreather, in

extreme cases, may lead to a total failure.

Important: Always close the mouthpiece before removing from your mouth.

This rule applies whether on land or in water . Mouthpiece

open when in your mouth. Mouthpiece closed when out of

your mouth

Breathing Hoses Breathing hoses with mouth piece

and connection threads. The mouth

piece is opened and closed by

using the stainless steel extension

arm which rotates the inner portion

of the mouthpiece. The

connections can only be attached

in correct orientation as the thread

sizes are different from left and

right.

14

Chapter 2 Assembling the SF2

Step 1

The counter lung/water trap bag is fitted onto the middle section using the securing plate

and six screws.

Only the first lip of the bellow on the counter lung is sandwiched between securing plate

and middle section.Make sure that the Retaining Ring fig12 is inside the counter lung before

attaching to middle section.

Step 2

The securing plate with the counter lung is now screwed onto the middle piece (Fig 13)

making sure that the first lip of the counter lung is sandwiched between securing ring and

middle section as it acts as a seal . It is recommended to tighten the screws a little more

than hand-tight do not over tighten.

Fig12 Fig13

Step 3

The Retaining Ring (inside the counter lung) and the outlet valve are screwed together.

Ensure that the six screws are tight and there is a good seal all round the securing plate.

Fig 14 Fig 15

Warning: Ingress of water can impair the function of the SF2 and in extreme

cases cause a total failure. Although the SF2 can tolerate a large amount of

water ingress and flood recovery is possible bailout is the required procedure.

Outlet Retaining

valve Ring

15

Step 4

The middle section with the screwed-on counter lung (Fig 23) is inserted into the bottom

section.

Fig 24 shows how the middle piece is inserted into the foot. This position ensures a proper

orientation of ADV and manual add inlet pipe. Fig 23 Fig24

Fig25

Step 5

The Upper Section is attached in the right

orientation as this has a slight taper and only fits

one way over the large O ring fitted to middle

section.

16

Step 6

Filling the Soda Lime Canister (Scrubber)

It is very easy to change the soda lime: remove the soda lime canister, loosen the wing nut

in the middle of the container, remove the tension spring plus washer and pull out the mesh

cover, empty the used soda lime into a suitable container for later disposal.

Making sure there is no used soda lime remaining, proceed to fill canister with new soda

lime by filling half way up the canister and tapping the sides to make sure there are no large

air spaces fill the remainder of the canister to 7mm below the bottom lip to allow for

refitting mesh. Attach the mesh onto the compressed soda lime granule and place tension

spring and washer over threaded rod tighten down with wing nut

Tighten the wing nut so that the tension spring is compressed fully. If the SF2 is being

transported with canister in place on rib or by car the tensioned spring helps prevent

channeling however the scrubber canister should be checked before diving.

After the soda lime canister has been filled, insert it into the upper section making sure the

three stainless steel feet on the bottom of the canister are resting evenly on the middle

section and check that the canister is properly fitted before continuing the assembly. Check

the O ring housed in the top part of the canister tube is clean and lightly O2 greased.

The canister tube is connected between head and middle piece please ensure that the O is in

good condition.

The soda lime container is filled (Fig 26)

It is essential that the soda lime is well compressed this is achieved by tapping the sides of

the canister

Mesh cover grid put on top (Fig27)

The tension spring with washer and plate on top (Fig28)

Properly compressed spring with the wing nut.The soda lime canister is now ready to use

(Fig29)

Fig26 Fig27 Fig28 Fig29

Danger: This process is very important, since loosely filled soda lime can

leave air spaces which can cause gas channeling. These channels allow

exhaled gas to track through the soda lime without removal of the CO2.

This can lead to hypercapnia and could lead to unconsciousness and death.

17

18

Step 7

Inserting the soda lime container(scrubber)

After the soda lime container has been filled, insert it into the upper section and check for a

proper fit before continuing with the assembly. The upper section is the connection between

head and middle piece and at the same time serves as a cover for the soda lime container

(scrubber). When attaching it a proper fit has to be ensured and O ring is free from debris

and slightly lubricated . Fig30

Soda Lime

In the soda lime container (scrubber), the carbon dioxide contained in the exhaled gas is

filtered. The chemical material in this container forms a mild carbonic acid from the carbon

dioxide in the exhaled gas and water vapour. This acid reacts with the soda lime material

producing the following by- products, chalk (Ca (OH) 2), moisture and heat. The amount of

absorbed carbon dioxide depends on the time that the gas has spent in the soda lime or dwell

time, the temperature of the soda lime. It is important that the Soda lime is packed correctly

to avoid “channeling” which would allow the CO2 to take a path of least resistance thus

allowing improper dwell time which could lead to CO2 breakthrough as the chemical reaction

has not taken place properly with this CO2 gas. Over packing can lead to increased work of

breathing and high CO2 during your course you will be shown the proper procedure to pack

your scrubber. It is vital that the user develops a solid understanding for how the rebreather is

assembled and used.

It is the responsibility of the diver to satisfy himself that the rebreather has been assembled correctly.

If the scrubber floods, it is possible that the diver gets pieces of the soda lime in his mouth.

The mixture of soda lime and water is known as a “caustic cocktail” and can be easily

avoided by connecting all parts of the rebreather properly.

The Chemical Reaction is two parts

Soda lime is probably the safest and cheapest material for dives. It consists of:

Calcium hydroxide Ca (OH) 2

Sodium hydroxide Na OH

Carbon dioxide reacts with water and water vapour and produces a mild carbonic acid:

Soda lime container (scrubber) is

inserted into the upper section of the

SF2 (Fig30)

19

1. CO2 + H2O = H2CO3

2. H2CO3 + 2NaOH = Na2CO3 + 2H2O + heat

H2CO3 + Ca(OH)2 = CaCO3 + 2H2O + heat

3. Na2CO3+Ca(OH)2= CaCO3 +2NaOH +heat

100 gram soda lime neutralize approximately 25 liters of carbon dioxide

The reaction is termed exothermic meaning it produces heat hence loop gas is warm and the

scrubber feels warm after your dive

Step 8

The Head of the SF2 All the sensors, the solenoid, a battery compartment delivering power to the solenoid, the

inhale as well as the exhale opening, the oxygen addition pipe work, the cables for the

Predator Fischer connector and the cover plate with its screw connected plus 3 O rings are

located here.

Fig31 Fig32

Inserting the batteries

Carefully remove the battery compartment's lid (Fig33)

Now insert the 3.6V AA battery and make sure that plus and minus are not mixed up (Fig34)

Now carefully reattach the compartment's lid (Fig35)

Fig33 Fig34 Fig35

Inserting/Changing the Oxygen Sensors The oxygen sensors are always displayed in the same order on the hand set. It is of advantage

to label both the sensors and the cables in the head of the SF2 in order; this simplifies the

search for single sensors if they have to be exchanged. Only sensors by Analytical Industries

must be used.

20

By using other brands or using it after expiry it is possible that wrong values may be

displayed and you dive with an unknown gas content in the breathing loop.

The sensors are housed in the designated recesses (Fig36). The sensors are held in position by

three screws and a mounting plate. These screws and plate need only be hand tight over

tightening will crush the cells.All sensors in place as shown in Fig36. Fig36

For protection we now place the head cover plate on top (Fig42) and screw it together (Fig43)

Fig42 Fig43

Step 9

Placing the head on the SF2

The head is now placed on top of the SF2 upper section making sure O ring is in place clean

of debris and lightly lubricated with O2 grease making sure the head is evenly pushed into the

upper section. It should slide into its final position by applying a slight and even pressure.

The breathing tube openings have to face in direction of the bladder and back plate mounting.

The side tension catches can be hooked up and closed.

Fig44 Fig45

Expiry dates on the sensors must be adhered too

21

Step 10

Breathing Hoses Overview Fig 46

46a Mouthpiece

Fig 46b Exhale Side

Fig 46c Inhale Side

Before assembling the breathing hoses, you should first test them for leaks as follows:

The breathing hoses need to be checked for any tears, flaws or

damage and all connections are in place. The breathing hoses

need to be checked before every dive with a series of safety

checks as will be shown by your instructor.

Check O-rings on the screw connections which can only be

screwed on in one orientation : cleanliness and integrity of the O-

rings must be maintained at all times.

Place the O-ring in the designated groove of the mushroom valve

carrier.

Next put the mushroom valve on the outside of the mushroom valve

carrier (see Fig 46b) so that the locking tab can be guided through

the central hole of the mushroom valve carrier. By slightly pulling

it, lock the mushroom valve to the mushroom valve carrier.

Make sure that the mushroom valve on the exhale side is outside on

the left of the mouth piece.

Place the O-ring in the designated groove of the mushroom valve

carrier.

Next put the mushroom valve on the inside of the mushroom valve

carrier (see Fig 46c) so that the locking tab can be guided through

the central hole of the mushroom valve carrier. By slightly pulling

it, lock the mushroom valve to the mushroom valve carrier.

Make sure that the mushroom valve on the inhale side is inside on

the right of the mouth piece.

Inhale Side

Mushroom Valve

Mushroom Valve Carrier

O-Ring

Exhale Side

Mushroom Valve Carrier

Mushroom Valve

O-Ring

22

With the mouthpiece rotated to open position, breathe gently from the mouthpiece sealing

exhale side hose against the cheek you should hear the mushroom valves opening and closing

through the inhale hose but no feeling of gas against the cheek reversing this you should feel

gas against the cheek as the inhale opens and closes to double check breathe into the exhale

hose and you should feel no gas coming through the mouthpiece and using the inhale hose

you should feel the gas moving out of the mouthpiece

Fig47 Fig48

Fig49

Fig50

Danger: If the hoses do not pass this test, it is possible you have mushroom valve problems! You must not dive ! This is a life-threatening risk! Contact SF2 Instructor or a certified retail store!

Once the hoses have been checked they can be

screwed on to the SF2 (there can be no confusion to

attaching the hoses as they only screw together in

one orientation.) The screw connections are

different sizes .Make sure the mouthpiece has been

attached in the right direction inhale gas over the

right shoulder and exhale over left shoulder

23

Step 11

Diluent and Oxygen Cylinders (not included)

Diluent: Cylinder valve (G5/8“) with hand wheel left, pressure gauge hose, over pressure

valve, inflator hose, low pressure hose to ADV (automatic diluent valve) and low pressure

hose for manual ADD

Oxygen: Cylinder valve (M26x2) with hand wheel right, oxygen pressure gauge, over

pressure valve, low pressure hose to solenoid valve and low pressure valve for manual

ADD

The cylinder mountings (included with the rebreather) are screwed to the cylinders (Fig

51)

Fig51

The cylinder configuration is usually pillar valves to the bottom configuration, which means that the cylinders are mounted with the pillar valves pointing to the bottom of the SF2 . This method of mounting allows access to the pillar valves for turning on and off much faster than above your head . Fig52 Fig53

As seen from figs above attaching diluent and oxygen 1st stage is straight forward this

should be done before attaching cylinders to the rebreather . Ist stages need to be CE

approved and have adequate number of low pressure ports you will need at least three low

pressure ports.

SF2 recommends the use of separate cylinder for dry suit inflation

24

Step 12

Mounting the cylinders to the SF2

With the male part of the cylinder mounting located on the side of the cylinder, place the

male part into the female part of the bracket which is attached to the SF2, push the cylinder

towards the SF2 and press the unlocking pin that is on the female part of the mounting

bracket. As soon as the cylinder mounting is in position tight against the SF2, release the

unlocking pin.

Fig54

Step 13

Connecting the gas supply to the SF2

Located on the middle piece of the SF2 there is a 9/16 unf connection for the diluent gas, to

which the low pressure hose of the 1st stage of the diluent side is connected (Fig55).Black

arrow

On the head of the SF2 there is a 9/16 unf connection for oxygen gas, to which the low

pressure hose of the 1st stage of the oxygen side is connected (Fig56).Green Arrow Fig55

Common 9/16 unf connection for the attachment of the manual add manifold

25

Step 14

Attaching the bladder and back plate (not included)

Fig7 Fig58

Back plate Wing and Harness Fig57 & Fig58

As seen from the diagrams above any back plate, wing or harness system as long as they are CE

approved can be used for the SF2. This allows for streamlined approach and clutter free front as

there are no counter lungs in front and the manual add system is attached to the waist straps

Manual Adds (Optional Extra)

The SF2 has two manual adds one for the diluent side and one for the oxygen side,these can

be positioned on the waist belt of the harness or over the shoulder .The low pressure hoses are

connected through a common manifold to enter the SF2 unit at the middle section where the

gases enter the unit through the addition pipe as shown in Fig.24 &55 The manual adds give

the diver the ability to operate the rebreather in manual mode i.e The setpoint is controlled by

the diver manually adding Oxygen or if the ADV failed closed to adjust addition of diluent.

During your course you will be instructed in various skills which employ the use of the

manual adds

The manual adds kit supplied include all fitting and hoses ,it is recommended that flow stop valves be fitted in the event of a gas leak at the manual adds

Important: The manual adds when fitted to the harness need to be accessible to the

diver.

26

Shearwater Predator

Manual

Shearwater Predator

Revision 2.3 Shearwater Research Inc. 27

Table of Contents Introduction .................................................................................................................. 30

Features .................................................................................................................... 30

Decompression and Gradient Factors ...................................................................... 31

Display .......................................................................................................................... 32

Buttons ......................................................................................................................... 33

Menu ............................................................................................................................. 34

Basic Setup .................................................................................................................35

Display Elements Descriptions ................................................................................ 36

Simple Example Dive ................................................................................................ 42

Complex Example Dive ............................................................................................. 43

Menu Reference ......................................................................................................... 46

Turn Off .................................................................................................................... 46

Calibrate ................................................................................................................. 46

Switch Setpoint ........................................................................................................ 49

Select Gas ............................................................................................................... 49

Radio Station Gases ................................................................................................ 49

Switch to OC/CC ...................................................................................................... 50

Dive Setup+ ............................................................................................................. 50

Low Setpoint ....................................................................................................... 50

High Setpoint ........................................................................................................ 51

Define Gas ........................................................................................................... 52

Dive Planner+ ...................................................................................................... 53

NDL Display ......................................................................................................... 56

External PP02 Monitoring ................................................................................... 58

Dive Log Menu ......................................................................................................... 61

Firmware Upload and Dive Log Download Instructions ....................................... 62

System Setup+ ........................................................................................................ 65

Dive Setup ............................................................................................................ 65

Conservatism ................................................................................................... 65

OC Gases ............................................................................................................ 66

CC Gases ............................................................................................................. 66

02 Setup .............................................................................................................. 66

Cal. PP02 ........................................................................................................ 66

Solenoid Speed ................................................................................................ 67

Set SC Identity ................................................................................................. 67

Auto SP Switch .................................................................................................... 67

Shearwater Predator


Display Setup ....................................................................................................... 68

Units ................................................................................................................. 68

Brightness Range ............................................................................................. 68

Altitude ............................................................................................................. 69

Flip Screen ....................................................................................................... 69

System Setup ....................................................................................................... 70

Date .................................................................................................................. 70

Unlock Code ..................................................................................................... 70

Load Upgrade ................................................................................................... 70

Reset to Defaults .............................................................................................. 70

Error Displays ............................................................................................................ 71

Battery Change .......................................................................................................... 74

Storage ....................................................................................................................... 75

Shearwater Predator


DANGER

This computer is capable of calculating deco stop requirements. These calculations are

at best a guess of the real physiological decompression requirements. Dives requiring

staged decompression are substantially more risky than dives that stay well within no-

stop limits.

Diving with rebreathers and/or diving mixed gases and/or performing

staged decompression dives and/or diving in overhead environments

greatly increases the risk of scuba diving.

You really are risking your life with this activity.

WARNING This computer has bugs. Although we haven't found them all yet, they are there. It is

certain that there are things that this computer does that either we didn't think about,

or planned for it to do something different. Never risk your life on only one source of

information. Use a second computer or tables. If you choose to make riskier dives,

obtain the proper training and work up to them slowly to gain experience.

This computer will fail. It is not whether it will fail but when it will fail. Do not depend on

it. Always have a plan on how to handle failures. Automatic systems are no substitute

for knowledge and training.

No technology will keep you alive. Knowledge, skill, and practiced procedures are your

best defense. (Except for not doing the dive, of course.)

Shearwater Predator


Introduction

Features

• Depth, time and oxygen sensor display

• Buhlmann algorithm with gradient factors conservatism

• Imperial and metric displays

• Two set points, each of which can be set between .4 and 1.5

• A menu system that adapts to diving status

• Automatic turn off after 30 minutes on the surface

• Depth sensor rated to 450 feet

• Dive Planner

• Any combination of oxygen, nitrogen, and helium

• Open and closed circuit, switchable during a dive

• 5 CC and 5 OC gases

• Gases can be changed and added during a dive

• CNS tracking

• No lockout

• Automatic setpoint switching (configurable)

• Battery life of over 100 hours of diving or 1 year of standby

Shearwater Predator


I } '

Decompression and Gradient Factors

The basic decompression algorithm used for the computer is Buhlmann ZHL-16C. It

has been modified by the use of Gradient Factors that were developed by Erik Baker.

We have used his ideas to create our own code to implement it. We would like to give

credit to Erik for his work in education about decompression algorithms, but he is in no

way responsible for the code we have written.

The computer implements Gradient Factors by using levels of conservatism. The levels

of conservatism are pairs of number like 30/85. For a more detailed explanation of their

meaning, please refer to Erik Baker's excellent articles: Clearing Up The Confusion

About "Deep Stops" and Understanding M-values. The articles are readily available on

the web. You might also want to search for "Gradient Factors" on the web.

The default of the system is 30/85. The system provides several settings that are more

aggressive than the default.

Don't use the system until you understand how it works.

Pressure Graph: Gradient Factors

A Gradient Fac.1cr is simply a

r --..------

M-value Gradicflt ----., ., ,

1 J. .6 .c. .2 D

GF lo gei'B(lteS

first stop

decimal fraction (or p HC mta!Jet of lhe M-value Gradient. Gradien1 Factoi!S (GF) are dffiined bet'tween zero ,and one,

0 GF.!: 1.

A GrndienlFac'lor oi 0 represens

the ambient pressure line.

rear l'tlnd.i:.lrt fur gradual dlimgein

Grad nt F l:o

A Gradient Fao1or of 1represents the

M-value line.

Gradient Factors modify the original M-value eq;uaoon:s fur con ervatism within 1Re decomPfessioo zooe.

' "---GF HI (surtaong v.:ltue) ntaintaiRS sa :-: y margin h'rs;l

s

0.-------------- Ambi«<lProssum, absoJuln

---

The lower Gtradient Factor value

(GF Lo) delermines •he depth ai

Lhe first srop. Used to generate deep Slops to the dth of1he ·a:eepest po ie deco s.1np."

Graph from Erik Baker's "Clearing Up The Confusion About Deep Stops"

Shearwater Predator


Display

The display has five areas. There are three title areas and three

data display areas.

Across the top line is the title for the first row of information. This

area only changes during the display of the dive log. The first data

area shows depth, battery warning, dive time, ascent rate, first stop depth, and first stop time. It

is showing a depth of 34.7 meters, a low battery alarm, 15 minute dive time, a 3 meter per minute

ascent rate, and a stop at 24 meters for 1 minute.

The low battery indicator glows yellow after the battery is less than 3.28V for 30 seconds. Below

3.15V the battery indicator will flash red. You will need to change your battery immediately.

It is recommended to change your battery when the battery indicator steadily glows yellow.

The ascent rate indicator shows 6 levels of ascent rate. Each block represents either 10 fpm or

3 mpm. 1, 2 and 3 bars will be green, 4 and 5 bars will be yellow, 6 bars will be red. When the

ascent rate is greater than 6 units, the whole block will be filled in red, and it will flash.

If you are above the indicated stop depth, the stop depth will flash red.

The next data line has the three 02 sensor readings. If a sensor is voted

out, it will display the current value, but it will flash and the value will not be considered in the average PP02. This area will also display fixed

PP02 or nothing in OC models.

The next area is the title for the bottom line. This title changes frequently in the menu system to

provide additional information about the bottom line. The last line shows that the computer is in

closed circuit (CC) mode with a gas containing 21% oxygen and 0% helium.

lfthere is a gas programmed in the current mode (OC or CC) that would normally be used at the

current depth, the system will flash the gas contents in red to remind you to either switch gases,

or remove the gas if you aren't using it.

In addition, there is a context sensitive area at the bottom which is implemented when cycling

through menus.

The no decompression limit (NDL) is zero since we are in decompression, and the time to

surface (TTS) is 15 minutes.

The computer works in both metric and imperial for depths and temperatures. The depth shows

a decimal point when the depth is between 0 and 99 meters. It shows no decimal point if the

display is set to feet.

To turn the computer on, press both the MENU and the

SELECT buttons at the same time.

Shearwater Predator


Buttons

MENU (Left)

• From the default display, pressing MENU brings up the menu.

• Once in the menu system, MENU moves to the next menu item.

• If the current function is an edit, pressing MENU increments the current display.

SELECT (Right)

• In the menu system, the select button saves the current value or executes the command.

• Out of the menu system, the select button brings up information displays.

BOTH BUTTONS

• When the computer is off, pressing MENU and SELECT at the same time will turn the

computer on.

The left button (MENU) can be used to scroll through the menu.

Please note, the menus vary depending on the various models.

When the "Switch Setpoint" menu item is displayed, MENU will

move to the "Select Gas" menu item.

The right button (SELECT) is used to accept the current choice.

Pressing SELECT with this screen displayed will enter the Select

Gas function.

In the "Select Gas" function, MENU increments the gas number.

SELECT would select closed circuit gas 2.

Shearwater Predator


When the system is not in a menu, pushing SELECT will bring up

information displays with various dive status information. This is

the first information display showing the diluent PP02 amount, the

current CNS loading, the setpoint (if applicable), and the average

PP02 being used for decompression calculation.

Menu

The system is designed to make the selection of the common operational functions while

diving easy. The menu selections are separated into two sets. The "Operation" menu is to

provide easy access to commonly used functions. The "Setup" menu is to change system

settings.

The system will continue to read the sensors and update the sensor display while you are in

the menu system.

If no buttons are pushed for a minute, the menu system will time-out. Anything that had been

previously saved will be retained. Anything that was in the middle of editing will be discarded.

A key characteristic of the menu system is that it is adaptive. It uses the information

that it knows about its current state to only ask questions or offer menu items that

make sense given the current situation.

For example, on the surface, the first menu item you will see is Turn Off. During a dive,

the Turn Off menu item doesn't appear.

The second menu item is Calibrate. That item only shows on the surface. In addition,

it only shows on models that have external sensors enabled, and on those models,

only when they are in closed circuit mode.

Shearwater Predator


The full menu structure is below:

• Turn Off

• Calibrate

• Switch Setpoint

• Select Gas

• Switch Open Circuit I Closed Circuit (Open Circuit I Semi-Closed Circuit)

• Dive Setup

• Edit Low Setpoint

• Edit High Setpoint

• Define Gases

• Dive Planner

• NDL Display

• External PP02 Monitoring

• Brightness

• Dive Log

• Display Log

• Upload Log

• Edit Log Number

• Clear Log

• Setpoint -> .19

• System Setup

• Dive Setup

• OC Gases

• CC Gases

• 02 Setup

• Auto SP Switch

• Display Setup

• System Setup

The Turn Off, Calibrate, Dive Log, Setpoint -> .19, and System Setup menus are only available

on the surface. This is the menu during a dive:

• Switch Setpoint

• Select Gas

• Switch Open Circuit I Closed Circuit (Open Circuit I Semi-Closed Circuit)

• Dive Setup

• Edit Low Setpoint

• Edit High Setpoint

• Define Gases

• NDL Display

• Brightness

Shearwater Predator


The status screens are:

• Gases, no-decompression limit and time to surface

• Diluent PP02, CNS, and average PP02

• Oxygen sensor millivolts

• Max depth, average depth, average atmospheres

• Water temperature, current Gradient Factor, current fixed Oxygen

• GF99, decompression ceiling, time-to-surface in 5 minutes and time-to-surface

• Battery voltage

• Pressure

• Date and time

• Surface interval

• Serial number and version number

Basic Setup

Before using the computer there are several things that need to be configured. This is not an

exhaustive list of the pre-requisites for diving the system, but a suggestion of key tasks.

On a system with external oxygen sensors, calibrate the oxygen sensors.

In the System Setup menu set the units to metric or imperial, also set the date and time.

Depending on the model of computer, enter the gases that you will use for the closed circuit

portion of your dive, and/or enter the gases for you will use for open circuit.

The system will use the gases that are available in the order of oxygen content during the Time

To Surface (TTS) prediction. The system will use the next available gas that has a PP02 of

less than 1.0 for closed circuit diving.

If the computer is in open circuit or is switched to open circuit during a dive, the system will

calculate the TTS based on the configured open circuit gases that are available. It will use the

next available gas that has a PP02 of less than 1.6 for open circuit diving.

NOTE: These gases are used automatically only for TTS predictions. The gas used to

calculate the current tissue load and the current ceiling is always the gas actually selected by

the diver.

Shearwater Predator


Display Elements Descriptions:

Closed-Circuit Partial Pressure of 02

(PP02):

The CC PP02 display depends on the Predator model:

All models Flash Red PP02 when less than 0.4 or greater

than 1.6.

Controller (PRC):

Displays 3 sensors.

Displays PP02 in when sensor is voted out.

Displays when calibration is not valid.

When in OC mode, the sensor values continue to display.

This shows the state of the breathing loop, but not what is

currently being breathed.

PROCT-E:

Can show external sensor PP02 (will show three values) or

internal PP02.

See PROCT for internal PP02 description.

Displays 3 sensors.

Option to show only middle sensor. To show middle sensor

only, perform calibration with only sensor 2 connected.

Displays PP02 in when sensor is voted out.

Displays when calibration is not valid.

When in OC mode, the sensor values continue to display.

This shows the state of the breathing loop, but not what is

currently being breathed.

PROCT (or PROCT-E in internal PP02 mode):

Internal PP02 mode only.

Shows the current setpoint, which is the PP02 at which the

Predator assumes the breathing loop is being maintained.

Shows 1 value only.

When in OC mode, the value disappears.

PROT (open circuit only model):

Not available. See GasPP02 instead.

Shearwater Predator


Fraction Inspired 02

(Fi02):

The fraction of the breathing gas composed of 02 . This value

is independent of pressure.

Ascent Bar graph:

Imperial: Shows 1 bar for every 10 feet per minute (fpm) of

ascent rate.

Metric: Shows 1 bar for every 3 meters per minute (mpm)

of ascent rate.

Green when 1 to 3 bars, when 4 to 5 bars, and

Flashes Red when 6 bars or more.

Battery Symbol:

When the battery is good, the battery symbol does not

display.

Displays when the battery needs to be changed.

Flashes Red when the battery is dangerously low and must

be replaced immediately.

Depth:

Shows the depth in the currently selected units (feet or meters). Meters are displayed with 1 decimal place up to

99.9 meters. Feet are never displayed with a decimal place.

Note: If the depth shows a Flashing Red zero, then the

depth sensor needs service.

Dive Time:

The length of the current dive in minutes. Does not display when not diving.

Stop Depth and Time:

Stop- the next stop depth in the currently selected units

(feet or meters).

Time- the time in minutes to hold the stop.

Will Flash Red when you ascend shallower than the current stop.

Note on 1Oft/3m last stops: The Predator uses 1Oft/3m

last stops. You may perform 20ft/6m stops with no penalty,

since the Predator is always calculating tissue loading at

your actual depth. The only difference is that the predicted

time-to-surface will be shorter than the actual TTS since off-

gasing is occurring slower then expected.

Shearwater Predator


Average Depth:

Displays the average depth of the current dive, updated once

per second.

When not diving, shows the average depth of the last dive.

Average Depth in Atmospheres (AvgATM):

The average depth of the current dive, measured in absolute atmospheres (i.e. a value of 1.0 at sea level).

When not diving, shows the average depth of the last dive.

Circuit Mode:

The current breathing configuration. One of: OC = Open circuit

CC = Closed circuit SC = Semi-closed circuit

Current Gas (02/He):

The current gas shown as a percentage of Oxygen and

Helium. The remainder of the gas is assumed to be Nitrogen.

In closed circuit mode, this gas is the diluent. In open circuit

mode this is the breathing gas.

Flashes Red when there is another programmed gas that is

more appropriate at the current depth than the current gas.

No Decompression Limit (NDL):

The time remaining, in minutes, at the current depth until decompression stops will be necessary.

Displays in !lie when the NDL is less than 5 minutes.

Once the NDL limit has been exceeded, this value can be

set to optionally display other information. These options are:

CEIL: The current ceiling in the currently selected units (feet

or meters). Flashes Red if you ascend shallower than the

current ceiling.

GF99: The raw percentage of the Buhlmann allowable

supersaturation at the current depth.

@+5: The time-to-surface (TTS) if you were to stay at the

current depth for 5 more minutes.

Shearwater Predator


Time-to-Surface (TTS):

The time-to-surface in minutes in the current circuit mode.

Assumes an ascent rate of 30 feet per minute (10 meters per minute), that stops will be followed and programmed gases

will be used as appropriate.

Maximum Depth:

The maximum depth of the current dive.

When not diving, displays the maximum depth of the last

dive. CNS Toxicity Percentage:

Central Nervous System oxygen toxicity loading percentage.

Flashes Red when 100 or greater.

The CNS percentage is calculated continuously, even when

on the surface and turned off. Removing the battery will reset

the CNS percentage.

Setpoint:

The current PP02 setpoint. Displays in !lie when the

setpoint is 0.19.

Average PP02: The average PP02 of the current breathing gas.

In OC mode, displays in Flashing Red when less than 0.19

or greater than 1.65.

In CC mode, displays in Flashing Red when less than 0.40

or greater than 1.6. In CC mode, averages all sensors that

are not voted out.

Diluent PP02:

Only displayed in CC mode. Displays in Flashing Red when

the partial pressure of the diluent is less than 0.19 or greater

than 1.65.

Gas PP02:

Only displayed in OC mode. Displays in Flashing Red when

less than 0.19 or greater than 1.65.

Gradient Factor:

See "Clearing up the Confusion About Deep Stops" by Erik Baker

Shearwater Predator


Pressure:

The pressure in millibars. Two values are shown, the surface (surf) pressure and the current (now) pressure.

The current pressure is only shown on the surface (i.e. when

not diving).

The surface pressure is set when the Predator is turned on.

If the Altitude setting is set to Sealvl, then surface pressure

is always 1013 millibars.

Temperature:

The current temperature in degrees Fahrenheit (when depth

in feet) or degrees Celsius (when depth in meters).

External Voltage:

The external voltage of the solenoid battery. Not available on

all models.

Internal Voltage:

The Predator's internal battery voltage. Displays in

when the battery is low and needs replacement. Displays in

Flashing Red when the battery is critically low and must be

replaced as soon as possible.

Millivolts:

The raw millivolt readings from the PP02 sensors. Only

available on models with external monitoring.

Date and Time

In the format mm/dd/yy 24-hour clock time.

Serial Number:

Unique serial number identifier for every Predator.

Version:

The version number indicates the features available on the Predator computer.

The last two numbers are the firmware version.

Surface Interval:

The time in days, hours and minutes since the last dive

ended. Reset when the battery is removed.

Shearwater Predator


Simple Example Dive

Here is an example of a simple air dive. It will help to introduce the screen displays as the

diver progresses.

As the dive starts, the depth increases. The display is showing the computer programmed for open

circuit (OC) air.

As we pass through 30 feet, the time-to-surface (TTS) shows one minute. This shows that the

computer is expecting the diver to ascend at approximately 30 feet per minute or 1 meters per minute.

The dive predictions are based on this ascent rate.

The no-decompression limit (NDL) starts off showing 99, but then starts to show a smaller number as

the depth increases. The 3rd screen above shows that we will go into deco in 12 minutes.

As we ascend, the ascent rate indicator shows about 30 fpm or 9 mpm. When we approach

the first stop, our ascent rate slows to about 10 fpm and when we go shallower than our first

stop, the stop depth starts to flash red.

When we clear the last stop, the stop depth and time goes blank, and now we see a NDL of 99

minutes again. Once we surface, the depth is 0 and a minute later when the computer comes

out of dive mode, the NDL goes to 0 as well.

Shearwater Predator


Complex Example Dive

This is an example of the displays that might be seen on a dive. This example shows a

complicated dive with multiple Closed Circuit (CC) gases and multiple Open Circuit (OC) bail-

out gases. A normal, single gas CC or OC dive wouldn't have any button pushes at all, so

there isn't much to show.

The first step is to calibrate. Since we are on the surface and not diving, MENU will bring up

"Turn Off'', then "Calibrate." Once the loop is flushed with oxygen, SELECT will bring up the

confirmation display, and another SELECT will calibrate.

Next, we check the closed circuit gases that we have programmed. Entering the gas selection

function by pressing SELECT with the "Select Gas" menu item showing will display the first CC

gas that is available. MENU will increment to the next gas available. Another MENU takes us

back to the "Select Gas" menu item. Those are the only two gases configured. We SELECT

gas number 2, the Trimix 10/50.

The system will use both of these gases for our dive when calculating the TTS. It assumes

a diluent switch at a PP02 of 1.0. That means that it will assume that you have switched to

an air diluent at 124 feet. This is only for TTS. The computer will always use the currently

selected gas for tissue loading calculations.

Then we switch to open circuit to look at our bail-out gases. Flipping through the gases with

MENU shows that we have three gases available. (Whether they are appropriate gases is a

subject for one of the web forums.)

Shearwater Predator


These are the gases that will be used to estimate TTS in the event that you switch to open

circuit during a dive. The computer will assume that you will switch gases when the PP02 of

the next available gas is less than 1.6.

Automatic decisions of when to switch gases for the TTS calculation means that it is very easy

to set up your CC and OC gases. There is no need to enter a depth or a PP02 to switch gas.

There is no need to keep track of which gases are turned on and off in which mode.

If a gas is available in the CC gas list it will be used in CC, and it will be used at an appropriate

depth. The same is true for OC. It is always configured correctly if you actually have the

gases you have created.

If it is necessary to switch to OC while diving, 4 button pushes will do it. You will be switched to

OC and will be using the gas that has the highest PP02 less than 1.61. Your OC gas list is

likely very different from your diluent gas list, but all of the OC gases are automatically selected

and available.

Now switch back to closed circuit and start the dive.

We have reached a depth now that will incur decompression soon.

The NDL is 8 minutes, and the TTS is 4 minutes. The TTS just

reflects the ascent time at 30 fpm.

The computer has automatically switched to the high setpoint. This

can be disabled if automatic setpoint switching isn't required.

We are now at our maximum depth. Our first stop is at 90 feet.

The diver is ascending to the 90 foot stop. Note the ascent rate

indicator showing a 30 fpm I 10 mpm ascent rate. Although the

ascent rate is 30 fpm now, during the 7 minute ascent, the diver

ascended slower than was predicted, and now there is a 100 foot

stop.

Shearwater Predator


But the diver missed the stop, and has ascended to 95 feet. At this

point, the stop depth and time is flashing red to show that the depth

is above the recommended stop.

The diver switches to the other programmed CC gas, air. Note that

if you change the diluent on the computer you must flush the loop

to change the diluent in the loop. At the same time the 100 foot

stop clears. It is common for the first stops to clear in less than a

minute. They mainly just slow down the ascent.

At 60 feet a problem develops that causes the diver to bail out to

open circuit. The first push on MENU brings up Select Gas.

The second push brings up Switch CC -> OC.

A push on SELECT does the switch. The system has switched

the gas set from the closed circuit gas set to the open circuit gas

set, picked the gas with the highest PP02 less than 1.6, and

recalculated the decompression based on the new profile.

At 20 feet, one push on MENU brings up select gas.

A push on SELECT enters the select gas menu, and another

SELECT picks the 02. Since the gases are sorted by oxygen

content, the 02 is the first gas offered.

This was a multi-gas trimix dive with a multi-gas open circuit bailout,

and it required 9 button pushes.

Shearwater Predator


Menu Reference

Turn Off

The "Turn Off' item puts the computer to sleep. This menu

item will only appear if the water contacts are dry on controllers.

While sleeping, the screen is blank, but the tissue contents are

maintained for repetitive diving. The "Turn Off' menu item will not

appear during a dive on any model. It will also not appear for 2

minutes after a dive to allow for a continuation dive.

Calibrate This will calibrate the sensor displays to oxygen. Flood the

breathing loop with pure oxygen, SELECT with "Calibrate" in the

display, and the confirmation message will display. On the top line,

the millivolt reading will show. Good sensors should be in the range

of 35- 60 mV at sea level in 100% oxygen. The valid millivolt range

for calibration is 30- 70 mV. This scales with percentage of oxygen

and barometric pressure.

Pressing the MENU button will prevent the calibration. Pressing

SELECT will calibrate the sensor displays. The displays should

now all read .98. If any display shows FAIL, the calibration has

failed because the mV reading is out of range.

The system defaults to a calibration gas of 98% oxygen. This is

to compensate for the difficulty in completely filling the loop with

100% oxygen and also to allow for water vapour. If you are using

a calibration kit with no water vapour and 100% 02, you can set

the calibration gas to 100. It can also be set to other values if pure

oxygen is not available.

The calibration takes into account the altitude at which the

computer was turned on. For example, if the altitude was 885 mBar

or .87 ATA, then with a 98% calibration gas, the sensors would

calibrate to .85.

The "Calibrate" menu item will not display during a dive.

Shearwater Predator


Calibration Problems

Here are some common calibration problems. In this display, one

sensor is flashing This shows that the sensor is voted out.

If it comes back within range, it will be voted back in, stop flashing

and return to green.

A failed sensor is a different situation. In this case, the sensor

failed calibration. Changing the sensor won't make it register

again. Once a sensor has failed calibration, the only way to bring

it back is to successfully calibrate. If the computer were to display

a value with a new sensor, it would be a meaningless value without

calibration.

If this was the display, it would indicate a faulty sensor. It is not

within the normal range for a sensor in oxygen. Most sensors are

designed to output 10 mV +/- 3 mV in air. If the output is linear,

then that translates to a range of 30 to 70 as valid mV readings

in 98% oxygen. The computer will refuse to calibrate outside that

range.

Three sensors all showing FAIL is usually caused by an accidental

calibration in air, or a calibration with the cable unplugged.

Plugging the cable back in won't change anything. Failed

calibrations can only be fixed by successful calibrations.

Shearwater Predator


Switch Setpoint

With a controller, when SELECT is pushed with either of these

displays, the displayed setpoint on the right will be selected.

During a dive, the "Switch Setpoint" menu item will be the first item

displayed. The "Turn Off' and "Calibrate" displays are disabled.

With a closed circuit computer that is not a controller, and does not

have external monitoring turned on, the switch is between 2 user

assigned set points.

Shearwater Predator


Select Gas

This menu item allows you to pick a gas from the gases you have

created. The selected gas will be used either as the diluent in

closed circuit mode, or the breathing gas in open circuit mode.

Gases are always sorted from most to least oxygen content.

Press the SELECT button when "Select Gas" is displayed, and the

first available diluent/gas will be displayed.

Use the MENU button to increment the diluent/gas to the one you

want, then press the SELECT button to select that diluent/gas.

If you increment past the number of gases available, the display

will fall back out of the "Select Gas" display without changing the

selected gas.

Use the "Confirm" button to select a gas. The bottom line of the

display shows the selected gas. An 'A' will appear next to the

currently active gas.

Radio Station Gases

For computer models that support open circuit and closed circuit operation, the system

maintains two sets of gases- one for open circuit and one for closed circuit.

The way they operate is very similar to the way car radios work with AM and FM stations.

When you are listening to an FM station and you push a station selection button, it will take

you to another FM station. If you add a new station, it will be an FM station.

Similarly, if you are in the AM mode, adding or deleting a station would add or delete an AM

station.

With radio station gases, when you are in open circuit, adding, deleting or selecting a gas will

refer to an open circuit gas. Just like the FM stations are selected when your radio is in FM

mode, the closed circuit gases are available in the closed circuit mode. When you switch to

open circuit, the gases available will be open circuit gases.

Shearwater Predator


Switch to OC/CC

Depending on the current computer setting, this selection will show

as either "Switch CC -> OC" or "Switch OC -> CC".

Pressing SELECT will select the displayed mode for decompression

calculations. When switching to open circuit while diving, the most

appropriate open circuit gas will become the breathing gas for

calculations.

At this point, the diver may want to switch to a different gas, but

since the diver may have other things to deal with, the computer will

make a "best guess" of which gas the diver would choose.

On computers with external oxygen sensor monitoring, there is also

an option to set the computer to calculate decompression

predictions using semi-closed circuit. This is enabled in the System

Setup menu.

You can also switch to from CC to OC on a fixed PP02 model and

vice versa.

Dive Setup+

These screens are showing controller displays.

Pressing SELECT will enter the Dive Setup sub-menu.

Low Setpoint

This item allows you to set the low setpoint value. It will display the

currently selected value. Values from 0.4 to 1.5 are allowed.

A press of MENU will increment the setpoint.

Press the SELECT button when "Edit Low SP" is displayed and

the edit display will be shown. It is set at the lowest valid value for

setpoint, .4.

Shearwater Predator


Another press of MENU will increment it again.

If SELECT is pushed, the currently displayed setpoint will be selected, and the display will return to the "Low SP" menu item.

If the highest allowable value, 1.5, has been passed, the value will

return to 0.4.

High Setpoint

The high setpoint function works exactly like the low setpoint

function.

Shearwater Predator


Define Gas

The function allows you to set up 5 gases in Closed Circuit and 5

gases in Open Circuit. You must be in Open Circuit to edit open circuit

gases, and you must be in Closed Circuit to edit closed circuit diluents.

For each gas, you can select the percentage of oxygen and helium in

the gas.

Pushing SELECT when "Define Gas" is displayed presents the function

to define gas number 1.

Pushing the MENU button will display the next gas.

Pushing SELECT will allow you to edit the current gas. The gas

contents are edited one digit at a time. The underline will show you the

digit being edited.

Each push of the MENU button will increment the digit being edited.

When the digit reaches 9, it will roll over to 0.

Pushing SELECT will lock in the current digit, and move on to the next

digit.

Pushing SELECT on the last digit will finish editing that gas, and bring you

back to the gas number.

Any gases that have both oxygen and helium set to 00 will not be

displayed in the "Select Gas" function.

Shearwater Predator


Pushing MENU will continue to increment the gas number.

Note: The "A" denotes the active gas. You cannot delete the

active gas. If you try, it will generate an error. You can edit it,

but cannot set both the 02 and HE to 00.

The computer will display all 5 gas entries available to allow you to

enter new gases.

Pressing MENU one more time when the fifth gas is displayed will return you to the "Define Gas" menu item.

Only enter the gases you are actually carrying on the dive. With radio station gases, the

computer has a full picture of the OC and CC gases you are carrying and can make in-

formed predictions about decompression times. There is no need to turn gases off and

on when you switch from CC to OC, because the computer already knows what the gas

sets are. You can still add or remove a gas during the dive if needed.

Shearwater Predator


Dive Planner+

INTRODUCTION:

• Calculates decompression profiles for simple dives.

• In closed-circuit (CC) mode, also calculates open-circuit (OC) bail-out (BO).

SETUP:

Uses the current gases programmed into the Predator, as well as the current GF low/high

settings.

Deco profile is computed for the current circuit mode (CC or OC).

ON THE SURFACE:

Enter the dive bottom depth, bottom time, respiratory

minute volume and PP02 (closed-circuit only).

Note: Residual tissue loading (and CNS%) from recent

dives will be used in calculating the profile.

DURING A DIVE:

Computes the decompression profile assuming the ascent

will begin immediately. There are no settings to enter.

(RMV is last used value)

Dive Plan Setup

LIMITATIONS:

The Predator Dive Planner is intended for simple dives. Multi-level dives are not supported.

The Predator Dive Planner makes the following assumptions:

• Ascent and descent rates are 33ft/min (1Om/min).

• For OC, the gas in use will be the gas with the highest PP02 less than 1.61.

• For CC, the gas in use will be the gas with the highest PP02 less than 1.05.

• Last stop is 1Oft (3m).

• For CC, the PP02 is constant for the entire dive.

• The RMV is the same while diving as during deco.

• Semi-closed is not currently supported.

Shearwater Predator


The Dive Planner does not provide any validation of the profile. It does not check for nitrogen

narcosis limitations, gas usage limitations, CNS percentage violations, or isobaric counter-

diffusion violations due to sudden helium switches. The user is responsible for ensuring a safe

profile is followed.

RESULT SCREENS:

The results are given in tables showing:

• Stp: Stop Depth

• Tme: Stop Time • Run: Run Time

• Qty: Gas Quantity

In feet (or meters)

In minutes

In minutes

in CuFt (or liters). OC and BO only

The first two rows are special, the first row showing the bottom time and the second showing

the ascent to the first stop. When diving, these two rows are not displayed.

Example Results Table for Closed-Circuit and Bailout.

If more than 5 stops are needed, the results will be split onto on several screens. Use the right

button to step through the screens.

For OC or BO profiles, a total gas consumption report is given.

Gas Usage Report

Shearwater Predator


The final result screen shows the total dive time, the time spent on deco and final CNS%.

Results Summary Screen

If no decompression is required, no table will be shown. Instead, the total No-Decompression-

Limit (NDL) time in minutes, at the given bottom depth will be reported. Also, the gas quantity

required to surface (bailout in CC) will be reported.

No Decompression Results Screen

Shearwater Predator


NDL Display

The NDL Display option allows you to display four different values

during the dive. The display can be changed during the dive to

provide different information.

Pushing SELECT will make the NDL display editable. The first

choice available will be NDL. If you select NDL, the NDL will

always be displayed during the dive whether or not you have a

decompression ceiling.

The next selection is CEIL. With this setting, as long as the NDL

time is 0 (you have a decompression ceiling), the raw ceiling will be

displayed instead of the NDL. This is the equivalent of the 'Man on

a rope.' It will show your ceiling without it being rounded up to the

next even 10 foot or 3 meter stop. Please note that there is very

limited information on the effects of following a continuous ceiling

instead of stopping at stops and only moving up to the next stop

when the stop has cleared.

It is the author's opinion that all stops should be honored. It seems

intuitive that if you have bubbles, and you stop, you give the

bubbles an opportunity to be resorbed. If you continuously ascend,

the ambient pressure is continuously reduced which prevents

bubbles from shrinking. Because of this belief, the computer will

give one MISSED DECO STOP message during the dive and one

after the dive, and will flash the stop depth and time in red as long

as you are above the stop depth. It will use the increased gradient

though, and your calculated off-gassing will be faster than staying

at the stops.

The next option is to display the actual supersaturation gradient for

a pure Buhlmann (99/99) profile.

The selection is GF99. With this setting, as long as the NDL time is

0 (you have a decompression ceiling), the gradient will be displayed

instead of the NDL.

The number shown is the percentage of supersaturation. The

number is calculated by reference to the Ambient Pressure Line

and the M-Value line. It can be thought of as the current GF, but

it is different in a couple of ways. First, the current GF generates

stops rounded to the nearest 10 feet or 3 meters. So a gradient

of 40 may reflect a ceiling of 15 feet, but the computer will show a

rounded-up 20 foot stop.

Shearwater Predator


Q)

:s 251 {g

I

This number can be used in several ways. First, it can be used to calculate an aggressive

ascent that still has some justification in decompression science. For example, if a diver were

to lose a significant portion of their gas and needed to get shallow fast, they could ascend until

they reached a gradient of 90, then stop until it dropped to 80, then ascend to 90 again, etc.

That would produce a Buhlmann-like profile with very little conservatism. In an emergency,

that may be an acceptable risk.

Another use might be to do a slower ascent on a dive to sightsee, but to stay in the

decompression zone by keeping the gradient above 0.

Another use would be to observe the

rapidly increasing gradient in the last

Pressure Graph: Gradient Factors

10 feet to the surface and slow that

ascent.

All of this is based on gradient theory

that may be completely false. There

is significant disagreement in the

Y -- ------------

-s 0 (/)

_o

m (f)

.8 .6 .4 .2 0 r- -- --

generates first stop

decompression research community

about the nature and practice of

decompression. Any techniques

described here should be considered

experimental, but the concepts may

be useful to the advanced diver.

a) £1 (/)

(/)

Q)

cL 01 (/)

m (9

t Q)

c Q)

E t m 0...

E 0

0

linear function for gradual change in Gradient Factors

GF Hi (surfacing value) maintains safety margin First

Stop

0+--- ---------------------------- 0 Ambient Pressure, absolute X

The last selection is @+5. This feature has been borrowed from Dan

Wible's CCR2000 computer. It is the time-to-surface (TTS) if you were

to stay at the current depth for five more minutes.

This can be used as a measure of how much you are on-gassing or

off-gassing.

Shearwater Predator


External PP02 Monitoring

The next menu item is used to turn external PP02 monitoring on

and off. By default, external monitoring is turned off and reads 'Int.'

for Internal. To turn external monitoring (Ext.) on, press the MENU

button to change from Internal to External, then press the SELECT

button on this menu item.

Now the PP02 of the the three sensors is displayed. In the

displayed screens, we have three sensors and they have been

calibrated at some point.

This system is plugged into three sensors and is the primary display

for the system.

Note that since we are in Closed Circuit mode, that the PP02 used

to calculate decompression is the average of the three sensors

after voting. In this case, sensor three has been voted out, and the

decompression calculation will use the average of sensor 1 and 2.

Sensor 3 will be flashing !llow.

Switching to Open Circuit mode..

The PP02 used for calculation is now is the PP02 of the selected

gas at the current depth.

If we now unplug sensor 1 and sensor 3, the computer will use

voting logic to pick the two sensors that agree and will think the

PP02 is 0. Sensor 2 will be voted out and flashing This

is one of those times that the user will have to determine which

sensors are correct.

Shearwater Predator


With sensors one and three unplugged, we simulate the situation

with fourth sensor monitoring. If we calibrate in this situation, the

system will assume that this computer is only attached to one

sensor, and will re-configure for fourth sensor monitoring.

It will no longer average the sensors or vote on them. Now the

single sensor is the only one considered and the PP02 used for

calculations is the PP02 of the single sensor.

Setpoint -> .19

This menu item will only be displayed on controllers and only on the

surface. It allows the solenoid to be turned off while on the surface

when the loop is exposed to air. This prevents the solenoid from

firing continuously. It is mainly used while uploading logs or other

maintenance functions.

To switch back to normal low setpoint, select the Switch Setpoint

menu item. The setpoint will also switch to normal low setpoint if a

dive is started with the .19 setpoint selected.

Shearwater Predator


Dive Log Menu

Display Log:

At the "Display Log" prompt, press SELECT to view the most

recent dive.

The profile of the dive is plotted in blue, with decompression

stops plotted in red. The following information is displayed:

Maximum depth

- Average depth

Dive number

Date (mm/dd/yy) and time (24 hr clock) of dive start

Length of dive in minutes

Press MENU to see the next dive, or SELECT to quit viewing

logs.

Upload Log:

See "Firmware Upload and Dive Log Download Instructions."

Edit Log Number:

The dive log number can be edited. This is useful if you need

to clear the dive log, but want the numbering to continue

from where you left off.

At the "Edit Log Number" prompt, press SELECT to begin

editing. While editing, use MENU to change the value ofthe

currently underlined digit, and SELECT to move to the next

digit.

The next dive number will be +1 from the value entered here.

For example, if you enter 0015, then the next dive will be

dive number 16.

Clear Log:

At the "Clear Log" prompt, press SELECT You will be asked

to SELECT again. Press SELECT to begin clearing the log,

or press MENU to cancel.

It will take about 1 minute to clear the log. Do not remove the

battery during this time.

Clearing the log will not clear the dive number.

Shearwater Predator


- ••

Firmware Upload and Dive Log Download

Instructions

Plug the Bluetooth dongle into your PC. Put the Predator within 6 inches of the Bluetooth

dongle.

Go to httP-:1/w_w_w.shearwaterresearch.com/Rages/library_ and download the most recent version

of 'Shearwater Desktop with Air' and the latest firmware update. Uninstall any old versions and

install the new Desktop.

If "Dive Computer" menu item is greyed out, the PC

cannot find a Bluetooth device plugged into it.

If you cannot connect to either 'update firmware' or

"download dive log" then you need to ensure that Bluetooth

is working on your PC or laptop. Ot12711!n'11· 1

U.1-'00 2 Ut14112001·11

Once you can access "dive computer" run the program and select 'Update Firmware' from the 'Dive Computer Menu.'

Select the Predator .AES file that is with the document.

-u..jg..._ p .. tDet D-

No firmware file sel ected =G

....)

Predator_V15.aes 1 .c.t"l..... 1

lnrtializt Btuotooth on Predator and atart

-

Start Closo

Now on the Predator, go to the "Dive Log" menu and select "Upload Log".

Shearwater Predator


The Predator screen will switch from "Initializing" to "Wait PC" which will have a countdown.

Now go back to the Shearwater Desktop. Click start from the open "Update Firmware Box", or

"Download Log." The PC will then connect to the Predator, and send the new firmware.

Predator_V15.aes j :solecti"U•... I

• ,,, • ,,, • Initialize. Btuatooth on Predator and abrt Connecting to ctve computaf.

Sen:ting 29%

-

Start Closo Cloae

Cion

The Predator screen will give percentile updates of receiving the firmware, then the PC will

read"Firmware successfully sent to the computer."

Firmware •ucc .tfully aant to dtve comput.r.

C lou

Shearwater Predator


The Predator will now Decrypt, which will take approximately 4 minutes.

Warning: Do not remove the battery during this time.

After decryption the Predator will process, which will take an additional 4 minutes.

The screen upon completion of processing will read 'Tissues Cleared' which must be

confirmed. The screen will then read 'Upgrade Reser which also must be confirmed.

The Predator now has the most up to date firmware.

Shearwater Predator


System Setup

System Setup contains configuration settings that are only set

between dives. This menu item doesn't appear during dives.

Each of the items in the System Setup menu can only be accessed

on the surface.

All of the submenus contained within System Setup make use of

a convenient user interface. The MENU and SELECT buttons are

context sensitive to each sub menu and individual setting.

When cycling through the sub-menus, MENU will carry the user

to the next sub-menu, while SELECT will allow the user to edit the

options in this submenu.

Once the user has pressed SELECT to edit a submenu, MENU

will cycle the user through the different submenu listings, while

SELECT will let the user edit those listings.

Once the user has pressed SELECT to edit a submenu listing

MENU will be used to change the context sensitive variable, while

the SELECT button will be used to move to the next field. Once

the user has pressed SELECT through all the fields, the new user

preferences will be saved.

Dive Setup

The first submenu is Dive Setup. The options contained here are the

same as those accessed from the "Dive Setup" section described

above, except under System Setup all of the functionality is

conveniently placed on one screen as opposed to the multiple

screens seen is the above described "Dive Setup" menu.

For a description of the functionality of each option, please see the

above "Dive Setup" section.

Conservatism

The final setting in the Dive Setup Submenu, conservatism, is not

found under the above 'Dive Setup' section. The Shearwater

Predator implements Gradient Factors by using levels of

conservatism. For a more detailed explanation of their meaning,

please refer to Erik Baker's excellent articles: Clearing Up The

Confusion About "Deep Stops" and Understanding M-values. The

articles are readily available on the web. You might also want to

search for "Gradient Factors" on the web.

Shearwater Predator


OC Gases

The second submenu is OC Gases. This menu allows the user

to edit the open circuit gases. The options contained here are the

same as those in the "Define Gases" subsection of the "Dive Setup"

section contained earlier in this manual. The interface conveniently

displays all five gases simultaneously.

For a description of how to appropriately set each gas, please see

the above Define Gas section

CC Gases

The third submenu is CC Gases. This menu allows the user to edit

the closed circuit gases. The options contained here are the same

as those in the "Define Gases" subsection of the "Dive Setup"

section contained earlier in this manual. The interface conveniently

displays all five gases simultaneously.

For a description of how to appropriately set each gas, please see

the above Define Gas section

02 Setup

The fourth submenu is 02 Setup. This menu allows the user to edit

the Oxygen settings.

Cal. PP02

This allows the user to set the expected PP02 for calibration. It is

used in three situations.

The first is when pure oxygen isn't available and the oxygen is

being generated by a membrane system. The oxygen in that case

might be 96% 02 and a few percent of Argon.

The second is when you are using a calibration kit and are assured

of using 100% 02 with no water vapour.

The third situation is for Semi-Closed rebreather use. SCR users

may not have oxygen available. If the SCR identity is selected, the

computer may be calibrated in air.

If any change is made in this screen, the current calibration will

be discarded. The computer must be re-calibrated with the new

settings.

Shearwater Predator


Solenoid Speed

The firing pattern of the solenoid can be changed between fast

and slow on controllers. The FAST setting uses frequent short

injections of oxygen and is generally more accurate.

The SLOW setting is more familiar to many users.

Set SC Identity

This function is used to switch between Semi-Closed circuit and

Closed circuit operation and is only available on the PROCTE. It

allows the computer to make accurate projections based on the

way the PP02 changes during ascents. It allows much more

accurate predictions for Time To Surface (TTS) for Semi-Closed

circuit divers.

It also allows SCR divers to set their calibration percentage to .21.

Note: When in semi-closed mode the user cannot utilize internal

monitoring.

In Semi-Closed mode you have the option of displaying the partial

pressure of oxygen (PP02) or the fraction of inspired oxygen (Fi02)

for the three oxygen sensor displays in the default screen.

Auto SP Switch

This feature is on controllers and computers with external

monitoring turned off.

Auto Setpoint Switch configuration sets up the setpoint switching. It

can be set up to switch up only, down only, both, or neither.

The first option is the switch up function. This configures the switch

up from the low set point to the high setpoint. Pushing MENU

switches it back and forth between "Auto" and "Manual."

Note: The Up Auto SP switch occurs during the descent.

Shearwater Predator


The next option is still a part of the switch up function, and enables

the editing of the switch depth.

Next is the switch down function. This configures the switch up from

the high set point to the low setpoint. Pushing MENU switches it

back and forth between "Auto" and "Manual."

The final option is still a part of the switch down function, and

enables the editing of the switch depth.

Either switch can be turned on or off independent of the other

switch.

The system limits the allowable setpoint settings. Switching up is

allowed from 20-999 feet and from 6-999 meters. Switching down

is allowed from 9-999 feet and from 2-999 meters.

If you enter a setting that is outside the allowed range, the existing

(valid) setting is retained with no change.

Display Setup

Units

The first 'Display Setup' changeable option is 'Units,' which allows

the computer to switch back and forth between Metric and Imperial

units of measurement.

Brightness Range

The next 'Display Setup' changeable option is 'Brightness' which

allows the computer to switch between four brightness settings:

Auto, Low, medium and High.

It should be noted that Shearwater Research suggests the use of

the auto function, as it makes use of a light sensor to provide

maximum brightness when there is an excess of ambient light, yet

will dim when there is less ambient light in order to conserve battery

life.

Shearwater Predator


Altitude

The altitude setting when set to 'Auto' will compensate for pressure

changes when diving at altitude. If all your diving is at sea level,

then setting this to 'Seavli' will assume that surface pressure is

always 1013 mBar (1 atmosphere).

Important: When diving at altitude you must set this option to 'Auto'

(the default setting is 'Sealvl').

Further, when diving at altitude, you must turn the computer on at

the surface. If the auto-on safety feature is allowed to turn the

computer on after a dive has started then the computer assumes

the surface pressure is 1013 mBar. If at altitude this could result in

incorrect decompression calculations.

Flip Screen

This function displays the contents of the screen upside down. This

is used for systems with a permanent connection to a rebreather. It

allows the computer to be worn on the right arm.

Shearwater Predator


System Setup

Date

The first 'System Setup' changeable option is 'Date,' which allows

the user to set the current date.

The date will have to be re-entered after a battery change.

Time

The next 'System Setup' changeable option is 'Time,' which allows

the user to set the current time.

The time will have to be re-entered after a battery change.

Unlock Code

The next 'System Setup' changeable option is 'Unlock,' which

allows the user to enter in an unlock in order to change models and

to set other features.

It can change a "PROT" OC Trimix computer to a "PROCTE", OC/

CC Trimix computer with external monitoring (only available on

cases with a fischer connector).

It can also change a PROT-SA, OC Trimix (no fischer connector) to

a PROCT-SA, OC/CC Trimix (no fischer connector).

Load Upgrade

The next 'System Setup' changeable option is 'Load Upgrade,'

which allows for the user download version upgrades.

The documentation on how to use the 'Load Upgrade' option can

be found in the above 'Firmware Upload and Dive Log Download

Instructions.'

Reset to Defaults

The finai'System Setup' option is 'Reset to Defaults'. This will reset

all user changed options to factory settings and clear the tissues on

the Predator. 'Reset to Defaults' cannot be reversed.

Note: This will not delete dive logs, or reset dive log numbers.

Shearwater Predator


Error Displays

The system has several displays that alert an error condition. All of these displays share a

common limitation of error alarms. There is no way to distinguish between an error alarm that

is not in alarm, and an error alarm that is broken.

For example, if an alarm is silent when it is not in alarm and is silent when it is broken, then

there is no way to be sure that the alarm isn't broken.

So by all means respond to these alarms if you see them, but NEVER depend on them.

Each of the alarms will display the message in yellow until dismissed. The error is dismissed

by pressing SELECT.

Other functions continue to operate as normal, so that the MENU button will take you into the

menu, and a push on both buttons will show the millivolt display. The error message will keep

returning until it is dismissed with a SELECT.

This message will appear if the average PP02 goes above 1.6 for

more than 10 seconds. It will come back after being dismissed if

the situation occurs again.

This message will appear if the average PP02 goes below 0.4 (.25

for SC) for more than a few seconds. It will come back after being

dismissed if the situation occurs again.

It is not unusual to get this error immediately after submerging

with a manual CCR and a hypoxic mix. The first breath after

submerging floods the loop with low PP02 gas. The situation is

usually resolved by increasing depth such that when the error is

noticed, the PP02 is no longer low.

This condition will also cause the "LOW PP OXYGEN" display to

appear. Here, the computer does not have two sensors that have

confirming values. There is no way to know the actual PP02, and

the average PP02 will be calculated as 0.00.

This message will appear when your internal battery reads less

than 3.2 v for 30 seconds. The battery needs to be changed. The

computer will also flash the battery symbol red.

Shearwater Predator

72

This alarm appears when the voltage on the external solenoid

battery is low (controller only). The solenoid may still be firing, but

the battery must be replaced before any further diving.

The external solenoid battery is measured during load, so it may

appear even though the battery looks good on a voltmeter.

This alarm will only appear once during a dive. When it is

dismissed, it will not return during the current dive.

This alarm alerts that the battery is not supplying enough power

for the solenoid to fire correctly, or the solenoid has failed, or the

connection to the solenoid has failed. (controller only)

If this alarm occurs, corrective action must be taken at once. Even

if the solenoid can be heard to fire, it is not functioning correctly.

This alarm will only appear once during a dive. When it is

dismissed, it will not return during the current dive.

This alarm is a notification that there has either been a very fast

ascent for a short period of time, or that there has been an ascent

of more than 66 fpm I 20 mpm maintained for over a minute.

This alarm may return after being dismissed if the condition occurs

again.

The alarm occurs when the diver has been above the minimum

depth for a decompression stop for more than one minute.

This alarm will only appear once during a dive, but it will also

appear once on the surface after the dive.

This alarm will show every time the computer loses power. All

decompression information has been lost.

Revision 2.3 Shearwater Research Inc.

Shearwater Research Inc. 73

This alarm happens when the computer does not complete all of its

tasks in the time allotted. It can happen occasionally from a

transient problem like a battery bounce after an impact. It can also

be the result of a hardware problem.

This reset shows up after a software update. This is the normal

event that shows the computer has been rebooted after the

software update.

This error usually occurs when the battery dies while the computer

is asleep. If the battery gets too low to maintain system integrity,

the hardware will force the system into reset.

The following messages are reporting internal hardware failures.

The system will continue to retry and may recover, but they would

normally mean that something that should never happen, has

happened. These messages should always be recorded and

reported to the factory or your local service center.

This is not an exhaustive list. There are other errors that could be

reported and more checks are added with each software update.

Battery Change

The Predator has a battery compartment in the side of the case.

With a large coin unscrew the battery cap.

Carefully pull out the battery holder. To prevent battery bounce and

rattling, it's fitted tightly, so you will need something like a dental

pick or a paper clip to pull out the holder.

Pull out the battery holder and change the battery. The battery is a

Saft LS14500.

The wires come from the main compartment of the computer

through to the battery compartment on one side of the battery

compartment.

The bottom of the battery holder is flat.


The bottom needs to be aligned with the wires

as they feed through the case. Carefully fold the

wires along the bottom of the holder and insert

back into the compartment. Care must be taken

not to pinch and score the wires.

Inspect and, if necessary, apply a light coat of

lubricant to the 0 ring on the battery cap.

Reinstall the battery cap taking care not to pinch

or deform the 0 ring.

Finger tighten with a coin. Do not over tighten.

Over tightening can cause the 0 ring to deform

and causes stress points on the case.

Storage The Predator dive computer should be stored dry and clean. Do not allow salt deposits to

build up on your dive computer. Wash your computer with fresh water to

remove salt and other contaminants. Do not use detergents or other

cleaning chemicals. Allow to dry naturally before storing.

Do not wash under high pressure as it may cause damage to the depth

sensor. Also do not remove the strap bracket assembly as it acts as

protection for the depth sensor

After cleaning, store the apparatus upright, out of direct sunlight in a

cool, dry and dust free place. Avoid exposure to direct ultra-violet

radiation and radiant heat.

75

76

Chapter 4

O-Ring Care and Maintenance

The SF2 rebreather is a highly precise underwater breathing device. The safe operation of

SF2 depends on all O-rings being inspected and cleaned before diving.

Middle section and head are radially sealed to the upper section and should be checked

cleaned and lightly lubricated before every dive.

Breathing hose head connections checked and lightly lubricated .

Soda lime canister most important O-ring checked and lubricated.

All of these O-rings are located in a specially designated groove, and have to be taken out of

these grooves for cleaning and maintenance. During this process, make sure that the O-rings

are not damaged.

After the O-rings have been removed, clean the groove first. This is easily done with a Q-tip

(cotton bud). Make sure that all dust and dirt as well as old grease is removed.

To clean the O-rings, simply take a clean, dry cloth and the O-ring, holding the cloth over

the O-ring between thumb and fore finger.Pull the O-ring through your thumb and

forefinger and again make sure that you remove all dirt. To grease the O-rings use oxygen-

compatibile grease,do not overload the O-ring with grease but just apply enough to give the

O-ring a „shine“.

Return the O-rings back in their grooves.

Before the SF2 is reassembled again, check that the seal faces i.e. the faces that meet the O-

rings are clean, free from scratches and other damages. Summary:

O-ring grooves cleaned and checked for proper condition.

O-rings checked for damages

O-rings slightly greased with oxygen compatible grease

O-rings reinserted into their respective notches

Seal faces cleaned and checked for potential damages

Maintenance

The SF2 has to be returned annually to the manufacturer or an authorised retailer for revision

and thorough servicing.

Information: Dive cylinders must have hydro check at least every 5 years and have a visual

inspection every year. Please refer to the manufacturer or your reatil store.

Regulators and cylinder valves should be oxygen serviced every year.

77

1st Stages Recommended regulators for the SF2 are Apeks Tec3, the oxygen side must be equipped

with a M26x2 connection thread.First stages should be CE approved and have at least 3 low

pressure ports to allow for over pressure valves to be fitted and low pressure hoses for

solenoid and adv connection .

Cylinders The SF2 is designed for the use of 3ltr cylinders

Filling the Cylinders The SF2 rebreather is operated using two cylinders. One is pure oxygen and the other diluent

gas Air or (Trimix 10/70). The pure oxygen replaces the oxygen that is used by the body.

Diluent of either Air or Trimix 10/70 is used to dilute the level of oxygen in the loop gas to a

breathable gas. Reminder: oxygen becomes toxic to the human body above a 1.6 PPO2. If

pure oxygen is breathed, you must not dive deeper than 6m.

The cylinders (oxygen and diluent air or trimix 10/70) of the SF2 should only be filled at a

certified filling station.

Clearing and Equalizing the Mask

The mask is equalized by exhaling through the nose during ascent and descent.The effect of

masking clearing cuauses loss of loop gas that is either replaced by ADV or manual addition

this will be demonstrated on your course

DANGER: It is dangerous to fill your cylinder yourself. Pleae follow all manafacturers recommendations

WARNING: Always use diluent gas that you have been trained to use.

Important: If you exhale through your nose constantly it is like diving with an open

circuit system. The gas supply will be used up quickly and the rebreather is less

efficient.

78

Breathing Hoses

Before assembling the breathing hoses, you should first test them for leaks as follows:

With the mouthpiece rotated to open position, breath gently from the mouthpiece sealing

exhale side hose against the cheek you should hear the mushroom valves opening and closing

through the inhale hose but no feeling of gas against the cheek reversing this you should feel

gas against the cheek as the inhale opens and closes to double check breathe into the exhale

hose and you should feel no gas coming through the mouthpiece and using the inhale hose

you should feel the gas moving out of the mouthpiece

Danger: If hoses are leaking you must not dive with it! This is a life-threatening risk! Please refer to SF2 Instructor or an authorised retailer.

79

Chapter 5 Pre-Dive Procedures

The SF2 is a high performance life support system that differs in certain areas with other

systems due to its compact, precise and simple design. The SF2 uses high quality materials,

the first class components, specially developed software, computer and sensors.

The technology has been tested in numerous dives under the most extreme conditions i.e

temperature and depth.It is still the responsibility of all SF2 divers to carry out all pre dive

checks to make sure the SF2 is working to the best of its capibilities

First Steps Before Diving

Soda Lime Canister

In chapter 1 the filling of the scrubber canister was explained be sure to note the scrubber

used time at end of each dive to allow for a total of 3hours. After a days diving keeping the

used soda lime in the unit to maximum of seven days as long as the dive time has not

exceeded or close to maximum of three hours. This 3 hour rule applies whether the

conditions are cold or warm

The reaction to an increased CO2 level in the loop gas e.g. due to usage or poor packing of

the soda lime, will lead to Hypercapnia see glossary of terms

Breathing Hoses, Postive & Negative Tests

As described in chapter 1 check hoses for mushroom valve function and leak testing,the

breathing hoses can then be screwed onto the unit making sure they are in correct

orientation.

Negative Test

Place mouthpiece in open position inhale through mouth and exhale through nose continue

until thers is resistance and no remaining gas make sure first stages and ADV are isolated

set

mouthpiece in closed position allowing no gas to enter system leave for at least five minutes

in this position. When you open the mouthpiece after this period of time you should hear a

rush of gas entering the system if not then check for leaks and redo the test

Warning: Always be aware and note scrubber time usage, if unsure of time or time left on

the scrubber pack a fresh scrubber .If manufacturer’s instructions are not followed may

lead to HYPERCAPNIA

DANGER: The tests must be completed. This allows the proper function of the SF2. If you

do not follow the instructions you expose yourself to dangers that can lead to injuries or

death.

80

Positive Test

First screw the overpressure valve on bottom of counterlung to closed position (clockwise)

this tightens the spring allowing the counterlung to pressurise when inflated .On this

occasion inhale through the nose and breathout through your mouth into mouthpiece which

should be in the open position .Continue until the overpressure valve on bottom of

counterlung allows gas to escape this confirms the valve is operating .Close mouthpiece

again try and prevent gas from escaping from the pressurised SF2 unit wait for at least five

minutes then open mouthpiece this time you should hear gas escaping from the SF2 unit

When both these tests have been carried out and no leaks detected srew overpressure valve

to dive position again you will be shown how to set this by your instructor on your course

for optimum performance

Cylinders

Prior to every dive, make sure that you have enough diluent (Trimix 10/70) and oxygen to

conduct the planned dive. The SF2 can utilize cylinders of different sizes but the size should

always reflect the objective of the dive undertaken.Bailout gas is recommended .These

options will be explained on the user course by your instructor.Start all dives with full

cylinders that have been analysied for gas content. Be aware of the maximum filling

pressure suggested by the manufacturer.

Mount the cylinders and screw all Ist Stages and hoses on. Slowly open the cylinders,

Check pressure gauge to verify pressure contents. Close the cylinders again and observe the

cylinder pressure for at least one minute,if the gauge drops in pressure check for

leaks.Reopen cylinders if the unit passes this test

Starting the Electronics

Battery State of Charge Test

Start the electronics by pressing both buttons, after the initial press the right hand button 6

times and 'Ext V Int V' show up in the fourth line of the display. Below that you find

numbers that give the voltage of the external and internal power supply. Replacement of

batteries will be covered in your course. EXT powers the solenoid INT powers the display

Battery voltage should be checked before every dive.

81

Calibrating the Oxygen Sensors

Calibrate This function allows the sensors to be calibrated in 98% oxygen to

allow for purity of gas . Manually add with pure oxygen and choose

'Calibrate', a message to confirm shows up. The mV of the power

supply are shown In the upper line, this value should be between 35

and 60mV in pure O2 at sea level for good sensors. Depending on the

ambient pressure and the purity of the O2, values between 30 and

70mV are also acceptable.

By pressing the 'Menu' button and then the 'select' button, the

calbration will be performed. All sensors should now display '.98'. If a

sensor is out of range it displays 'FAIL'.

Check Manual Adds

Manuals adds need to be checked if fitted by simple depression of the button checking there

are no leaks and the gas is entering the SF2 at the common manifold .Please check function

of gas isolaters if fitted

Pre- Breath

Breathing on the unit for 5 mins allows the diver to start the chemical reaction in the

scrubber canister also to check for leaks and CO2 by pass. It is recommended that this be

done with either nostrils pinched or wearing a diving mask to prevent contamination of the

loop gas from accidently introducing gas from the surroundings

Bailout Gases

Check that you have sufficent bailout gas for the intended dive and that drysuit and wing are

functioning .If fitted with either HUD or back up computer check these are set and

functioning correctly

Ready to Dive

Calibration should be performed at the start of every dive

82

Chapter 6 Diving Procedures

Monitoring Alarms Everyone who dives with the SF2 takes responsibility to monitor the alarms and react appropriately.

Breathing under Water Breathing with a closed circuit rebreather is very similar to breathing on the surface; on open circuit

the diver tends to demand gas through the regulator. The closed circuit diver has a much more natural

feeling of breathing plus there is less noise from bubbles of gas being exhaled as the gas in the closed

circuit rebreather is being recycled

Minimum Loop Volume

The exhaled gas goes into the counterlung and from there through the soda lime before it

finally reaches the inhale side and goes through the mouthpiece back into our lungs – this is

the loop gas content. Always try to enough gas the counterlung so that during a normal

breathing the ADV (automatic diluent valve) is not be activated and the over pressure valve

in the bottom of the counterlung is not opening.

Finding the right amount of loop gas volume is not difficult, as soon as we have reached our

final depth we slightly exhale through the nose, the gas volume in the loop drops and we

continue breathing normally.What you are looking for is if you inhale very deeply that you

just activate the ADV .As soon as you have found the ideal amount of gas in the loop you

will find it even easier to breathe and less impact on your buoyancy,you are less wasteful of

diluent.

DANGER: Never attempt to use the SF2 without proper training

This user manual is NO substitute for training. Without special training the use

of the SF2 can lead to severe injuries or even death. On the SF2 website

www.SF2-Rebreather.eu you can find the closest training center in your

vicinity or at your resort.

DANGER: NEVER ignore any alarms on your course you will be instructed

how to deal with these

Important: Even when diving with rebreathers, NEVER hold your breath.

83

Buoyancy Control Controlling your buoyancy with a closed circuit rebreather is different than with an open circuit. While in an open circuit your buoyancy is mainly controlled by either dry suit ,BCD or wing and fine tuning is achieved by inhaling or exhaling gas , this is not the case for rebreathers.The following is a quick guide only there is no subsitute for practice.Inhaling and exhaling the loop gas with have little or no effect on buoyancy it is controlled either by your Wing ,BCD or Drysuit and of course the removal of loop gas on ascent again you will be shown and the various methods on your course. As in your open water training weighting and trim are crucial,the best area to control buoyancy is in the shallow depths up to 10mtrs again understanding that inhaling and exhaling loop gas on rebreather is going to make little difference but adjusting your Wing ,BCD or Drysuit is the secret.

Removing Water from the Exhale Hose

During rebreather diving it is quite common to find some water accumulating in the exhale

hose due to either condensation or “loose lips” around the mouthpiece which tends to let a

little water in. The technique below should solve the problem of continuous bubbling noises

being heard whilst diving.

Move in an upright position, slightly lean to your left side (to the exhale side), look above

and stay in this position for a few seconds. Doing so, will give the water the opportunity to

flow into water trap in the middle section and into the counterlung. At this point if the diver

forcifully exhales this forces open the over pressure valve attached to the bottom of the

counterlung and the water can escape. During your course you will also be shown how in

the unlikely event water ingresses into the SF2 how using the manual add technique for

flood recovery.

Performing Ascents At the end of your dive ascending causes PPO2 to drop and loop gas and wing ,bcd or

drysuit to expand, if ascending at 10mtrs/min the computer will maintain set-point by

injection of O2 and you the diver control the expansion of gases by dumping manually from

wing,bcd or drysuit.The expanding loop gas is released by slightly releasing pressure on the

mouthpiece and letting the gas out through the side of your mouth.This needs to be

structured and slow not to allow you too be negative weighted and start to descend to depth

again or postively buoyany due to not allowing enough gas removalwhich can lead to a

uncontrolled ascent. Ascends and descends are best approached in a much slower method

than open circuit diving to allow for buoyancy,loop gas and controller adjustments and

keeping the PPO2 as stable as possible.

Ending the Dive As soon as you reach the surface, first establish positive buoyancy as you do with open circuit diving .Surface swimming with mouthpiece in you should still check PPO2 as regular as you did diving or shut mouthpiece and use bailout regulator to surface swim back to boat or point of entry.

Important: If you can control your buoyancy in shallow water (up to 10m), you

should find buoyancy quite easy to control in deeper water.

84

The electronics should only be shut down if back on the boat or point of entry when the unit has been taken off. If surface swimminng make sure the setpoint is in the low setting as the unit will try to maintain the higher setpoint and will be wasteful of gas and uncomfortable to breath.

Post Dive Care

• Close both cylinders (oxygen and diluent)

• Vent the oxygen and diluent systems

• Remove Cylinders for filling if required

• Remove Breathing Hoses and clean

• Remove head for drying of residual condensation

• Depending on dive time note scrubber time or refill with fresh soda lime

• Check counterlungs and rinse out any remaining moisture

Safe Diving with the SF2

• Always know your PPO2

• Always perform negative and postive tests before a dive

• Never hold your breath while diving with the SF2

• Always check hoses and mouthpiece mushroom valves

• Refill the scrubber canister after 3 hours of diving

• Always check the pressure of the cylinders (oxygen and diluent)

• Check the state of charge of the batteries before every dive

• Calibrate the oxygen cells before every dive

• Never ignore a warning

• If in doubt, bailout to your bailout system

Danger: Always make sure when mouthpiece is closed when not in your

mouth. The SF2 can deal with large amounts of water ingress but leaving

mouthpiece open could lead to electronics being flooded and diver becoming

negatively buoyant

85

Problem Solving during the Dive

Problem Solution

During your course you will be shown different methods to deal with the above problems that perhaps may allow you to stay on the rebreather these methods NEED to be practiced repeatly And should only be used as a last resort IF in doubt bailout to an open circuit system

Solenoid valve stuck open, high PPO2

Solenoid valve closed, low PPO2

Oxygen cylinder empty

Diluent empty

Leaking ADV

Oxygen cell error

Computer-electronics error

Flooded Rebreather

CO2 Excess (Hypercapnia)

Close oxygen cylinder, Bailout

Bailout

Bailout

Bailout

Close diluent cylinder, Bailout

Bailout

Bailout

Bailout

Bailout

Bailout open circuit system should be carried on every dive no matter what depth. Bailout gas: Air or an EAN mix apprioate for the diving depth

86

Chapter 7 Care and Maintenance after the Dive

After dive if a series of dives are going to be undertaken

• Put your SF2 in a secure place

• Shut down the electronics

• Close the oxygen and diluent cylinders


• Remove breathing hoses and hang it up for drying

• Check scrubber time and refill if required

• Consider detaching the head and putting it in a secure place for drying. Of course, this

is dependent on weather, dive site and entry point.

After Every Full Day of Diving

• Rinse the SF2 on the outside with fresh water

• Remove breathing hoses and rinse it thoroughly

• Hang up the breathing hoses for drying


• Detach the upper,middle and bottom sections on the SF2

• Remove the cylinders

• Detach the head

• Detach the head cover plate

• Check oxygen cells and dry if needed

• Take out the soda lime scrubber canister and empty the used soda lime into an

appropriate container for later disposal

• Rinse upper section thoroughly

• RInse the middle Section

• Remove and rinse the counter lung and over pressure valve

• Thoroughly rinse the water trap

At the end of a diving sequence we recommend disinfecting the unit

Disinfecting

For disinfecting we use Dettol Liquid Disinfectant. Follow the instructions on the product,

not more than 5% Dettol / Water in solution.

The parts that need to be disinfected are:

Breathing Hoses, upper section, middle section and counter lung.

After placing the parts in the Dettol water solution, rinse them thoroughly with fresh water

and let them dry in a well vented place.

When disinfecting the middle section, make sure that no water gets into

the opening of the low pressure connection to the ADV.

87

Long term storage and Maintenance

Follow the steps under 'After every Day of Diving' but in addition, disinfect the SF2

properly. Make sure that all parts are appropriately cleaned and dried, the O-rings are

greased with a thin film of oxygen compatable grease and the batteries are taken out from

the head.

Assemble the SF2 and put it in a clean, dry and frost-protected place.

The breathing hoses should be stored by hanging up to allow any moisture to drain.

Cylinders should be stored with 10 to 20 bars of gas . Make sure that the cylinders undergo

a visual inspection once a year and that the hydrostatic test is carried out when required.

Important to change the oxygen sensors on a 12 month basis

Travelling with the SF2

The SF2 is suited for travel, it is lightweight and can be broken down to its various

sections.The only requirement is that you check that the resort or dive charter can provide

cylinders and soda lime Make sure that you have access to cylinders at your destination and

that the supply with oxygen and diluent is sufficient. Soda lime is another issue that you

should address before departure, soda lime cannot be obtained everywhere.

It is advisable to carry some repair parts on your journey, e.g. batteries, sensors, mouth

piece and a bit of silicon grease.

Documents

User Manual - SF2-CCRsf2-ccr.co.uk/assets/downloads/SF2-user-Manual-Eng2.pdf · The operating temperature for the SF2 lies between a minimum of 4° Celsius and a maximum of 34° Celsius