Watch Keeping Training

7/26/2019 Watch Keeping Training

1/48

Watch Keeper

Training

Connecting rod

Piston

_~ ..Bedplate

~ ~Exhau~tpbrt

Botton l end

bearing

: ~_~

Crosshead

Air inlet

ports

hroud

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September 2 3


2/48

Watch Keeper Training Book

IBM - International 8afety ManaQement

IMO International Maritime Organization

A specialist agency of the United Nations created to provide co-operation among governments on technical matters

affecting international merchant shipping.

Created in 1948 as IMCO: Inter-Governmental Martime Consultative Organzaton

Internatonal Safety Management code ISM

International Convention for the Safety of Life at Sea SOLAS

lnternational Convention for the Preventon of Pollution from Ships MARPOL

Internatonal Convention on Load Lines

Convention on the InternationaI Regulations for Preventing Collisions at Sea

International Convention on Standards of Training, certifications and Watch-keeping for Seafarers

15M Code Internltiohal 5afety Mlnagement Code

A resolution issued by the IMO Every Company should develop, implement and maintain a safety management

system SMS , consisting of:

safety and environmental protection policy policy statement

instructions and procedures for safe operation of ships and protection of the environment

levels of authority and responsibilities and Iines of communication

procedures for emergencies

procedures for internal audits

The SMS Safetv Manaqement Svstem is a detailed description of

3

instructions and procedures for the safe

operation of our ships and the protection of the environment:

procedures and administration

responsibilities

communication

emergencies

audits

SMS for our company comprises of the following manuals and procedures:

Safety Management System SMS Manual

Shipboard Operations Procedures Manual SOPM

Head Office Procedures Manual HOPM

Emergency Contingency Plan ECP Ship based

Emergency Response Plan ERP Head Office based

A copy for the Technical Department is with the Chief Engineer. These manuals are updated when the Head Office

makes changes.

From SOPM index, highlight:

ship board organization - function descriptions

safety procedures safe working practices / hot work permit / confined spaces

training

Responsible for the SMS is the OP or OPA Desiqnated Person Ashore : John Seaman

He reports to the Director Marine Ops Mark Diamond and Managing Director Bernd GOlker

So called audits are done, for office and ships, regularly to check

3

procedures, level of training and familiarity with

procedures and administration.

Internal audits, every year by DPA

Engine Oepartment Manual

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Electrical Manual

S FETY SPE TS REL TED TO THE ENGINE ROOM ENVIRONMENT

1. personal health hygiene

Own responsibility

Work clothes to be changed frequently

Balance of work, rest and recreation

Simple infections can easily be spread (preventive measures and effective treatment)

Cuts and abrasions to be cleaned and given first aid treatment to avoid infections

Prolonged exposure to mineral oils can cause dermatitis and skin cancer, therefore wash hands (etc) and

working clothes frequently. Don t put oil soaked rags in pockets

drink much water (4 - 5 liters), extra salt when necessary

2. location of first aid box

Show location (at the moment left drawer watchkeepers desk)

3. procE)c:Jureor dealing with an injured person while on watch

First concern is sa.fety of one s own, then of other person

Call for help (Qridge 230 / info O

Iso late elec:trical pvvr if applicable

Do not (re) move if possible

Check pulse and respiration

Apply first aid if possible

Wait for help, but do not leave E/R without being relieved

4. Logos2 E/R workshop safety manual (?)

Logos2 Engine ISM manual page 22

Code of safe working practices for merchant seamen

1. Logos2 Engine ISM manual

Different types of personal protection equipment:

Working clothes: coveralls with long sleeves

No loose flaps etc. because of risk of being caught by moving parts or catching on obstructions

No finger ringsor otherjew~lry (whenwotkingwith machinery)

In the E/R safety footwear to be used (well fitting and not worn out)

Ear protection (plugs or ear muffs) to be us~d in E/R spaces

Gloves when working with sharp or hot objcts (not when walking stairs )

Face and eye protection (spectacles, goggles or facial shields) to be used when using grinding tools or

chipping

(Special face and eye protection to be used when welding)

Head protection (safety helmets) to be used when working in low areas or under open hatches etc.

Respiratory protection (dust masks, respirators, breathing apparatus) to be used when creating dust,

working with chemicals or in confined spaces

Respirator filter to be chosen in accordance with instructions

Safety harness or belt to be worn when working above 2 meters of height (aloft, outboard or below decks)

6. Safe working practices

don t run or jump in the E/R

beware of oily or wet floorplates

Beware of sudden / unexpected movements of the ship

(At sea) loose objects (open doors) to be properly secured (preparation for sea)

Instruction plates notices and signs to be kept clean and legible

Moving around in the E/R (marking of obstructions, moving through WTD s, temporary openings)

Touching in the E/R, hot areas

Walking stairs

Lifting heavy objects

Lock-out / tag-out (check isolation of systems, valves hydraulic and pneumatic pressure, electrical power)

Hot work permits (E/R manual appendix 3)

Working aloft (> 2 m), working on scaffolding or ladder


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Chemical storage

Use of handtools and portable appliances

7. Procedure for enclosed spaces

See permit for entry in enclosed spaces E/R manual appendix 3

8. Handling asbestos and other fibrous insulation material

- The inhalation of asbestos fibbers, even in concentrations too low to be readily detectable, may cause

serious lung disease or tumors.

Asbestos is commonly found in fire retardant bulkheads and thermal insulation and in friction materials

(brake linings)

Work area should be closed off

RElspiratory protective equipment should be worn

FuI protective clothing hould be worn (close fitting at the neck, ankles and wrists)

EVElryprecautiqn should be taken to avoid creation of dust:

U ing dustElxtractiol1 equiprnel1t

Using hand tools

Thoroughly wetting the material

Contaminated clothing and equipment to be vacuum cleaned (vacuum cleaner with suitable filter) before

taken off

Clothing to be washed separately

AII contaminated material to be disposed off

S FETV SPE TS REL TED TO THE ENGINE ROOM ENVIRONMENT ID

Location and use of fire fighting appliances and first response

1 plan of E/R with all fire-fighting appliances

2. Fire main system

discuss schematic with isolation valves

show location of pumps and valves

3. How to use different forms of fire fighting appliances

Show in practice

4. What to use different forms of fire fighting appliances for

Triangle of combustion: fuel / heat /oxygen

Starvation / cooling / smothering

- Fire classes European American

A flammable solids flammable solids

B flammable Iiquids fl. liquids and gases

C flammable gases electrical equipment

D flammable metals flammable metals

E electrical equipment

- Causes of fire:

1 smoking

2. spontaneous combustion (oily rags, boilersuits near a heat source)

3. Electrical

4. Welding

fire extinguishing agents

1

water - red - class A - cooling (and smothering by steam)

2. C02 - black - class B/C - smothering (no cooling)

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3. Foam - (yellow) - class B - smothering

4. Powder - blue - class A/B/C/(electric) - chemical

5. Wk s tirst response to tire

Find

I ntorm (bridge 230 / into O)

R estrict - shutdown ventilation

Close doors, hatches etc.

Check boundary areas

Remove tuel

tr

boundary areas

Start fire pump

Prepare fire hoses

E xtinguish

Fire prevention

Cleahing (removing oil and oi/y rags) is an importantpart

t

tire prevention

Prevention

oilleakage s

Use of metal containers tor combustible materals

Hot work should only be done after observing all appropriate precautions (hot work permit )

6. See below

7. How to operate WTD s

Can be operated from

1. The bridge

2. Local (2 ways)

3. Alleyway DR

Show in practice

8. See below

9. Emergencyescapes

- Know locations and where they lead

10. Shut down of venti/ation

- Show on alarmpanel and local starter panel

11. Checking and filling of sprinkler system

- Discuss schematic

- Show in practice

in nd emergency bilge system nd b ll st system

6. Action to be taken in case of an E/R tlooding

8. Main and emergency bi/ge

Ballast system

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FIR M IN SYST M

First response used to be, to start the emergency tire pump. Now tire main is constantly pressurized with cross-over

to sea c/w system cracked open

In case t real tire: start geny c/w pump and close cross over valve

Where to read the system pressure? How much should pressure be? 5-6 bar)

Pressure reliet valve in alternator room?

Pump is started but no pressure, what could be the reason?

Is pump really running?

Are valves open, suction / discharge?

Is pump deairated?

Is there a leakage? How many hydrants are open?

Loosing water but nowhere visible? Pressure reliet valve leaking?

Is the pressure gauge ok?

SPRINKL R SYST M

2000 Itr pr~ssure tank

Pressure: 6 bar

For watch keepers check pressure and water level

What it water level is too high / low emergency stop )

What it during a 4-hour watches the level drops continuously?

What should you dO?

Shore connection

t

sprinkler


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SAFE ENTRY OF ENCLOSED OR CONFINED SPACES

(Code of Safe Working Practices, Chapter 10)

Training t crew to involve the following:

* Recognition of circumstances and activities Iikely to lead to the presence of a dangerous atmosphere.

* The hazards associated with entry into enc/osed spaces, and the precautions to be taken.

*

The use of equipment and clothing required for entry into dangerous spaces.

* Instructions and drills in rescue from dangerous spaces.

RECOGNITION OF CIRCUMSTANCES ANO ACTIVITIES LlKELV TO LEAO TO THE

PRESENCE OF A OANGEROUS ATMOSPHERE

The atmo phere in an encIosed or confined sP:'ceis d:,ngerous, when it presents a risk to hea/th or life of any

person ehtering it. A dngeroUs situatih may occur throUgh:

- OXYGEN DEFICIENCY, or lack of Oxygen.

- Containment of FLAMMABLE GASES, VAPOURS OR FUMES.

- Containment of TOXIC GASES, VAPOURS OR FUMES.

Examples

t

potential hazards, Iikely to encounter are:

* The process of rusting combines the Oxygen and steel. In an enclosed space, the atmosphere will

Therefore have a reduced Oxygen /evel.

*

After emptying a fueltank, fue/ vapors may remain, causing lack of Oxygen in the tank.

* Lack of Oxygen may occur in boilers, where Oxygen absorbing additives have been used to

prevent corrosion.

* If C02 or Dry Powder have been used to extinguish a fire in a confined space, lack t Oxygen will

occur.

*

Fuel vapours remaining in an empty fuel or sludge tank are toxic.

* Gases produced by a tire, especially when involving plastics, can be very toxic

* Paint vapours, if painting in an enclosed space, are toxic.

* Fuel vapours are highly flammable.

2 THE HAZAROS ASSOCIATEO WITH ENTRV INTO ENCLOSEO SPACES ANO

PRECAUTIONS TO BE TAKEN

At first entry:

1 Obtain a Permit-To-Work. Ensure the actual entry is well planned, under supervision of an officer.

2. Make sure an officer is in charge, aware of what you are doing. He should assess the situation and

decide wether it is safe for you to work.

3. When opening the entrance to a dangerous space, care should be taken to avoid a sudden pressure

release or toxic vapour to be released from the tank.

4. Ensure the space is isolated, pipes are blanked, valves are closed. Mark the valves, so that they.cannot

be opened by accident.

5. The space or tank must be thoroughly ventilated, before someone enters to measure the Oxygen level.

6. Make all officers aware of what is happening, to avoid accidents.

7. Ensure the entrance and the space are well illuminated. Lights used must be explosion proof when

working with a possibility of flammable vapours.

8. Betore work can start in the space, the Oxygen content must be checked by a person wearing a

breathing apparatus. The tests must be done in corners of the space and between frames and beams, as

well as in the middle. Possible pockets of gas should be detected and removed by forced ventilation.

The Oxygen level regarded as safe i9 20% or more (max. 21%).

9

It an explosi-meter is on board, we should (especially in fuel and sludge tanks) also check the amount

of flammable vapours.

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10. Never let someone work alone in the space, without somebody at the entrance, keeping regular

contact.

11. At the entrance to the space the following equipment must be available:

- A breathing apparatus

- Spare aircilinders

- A lifeline with harness/belt

- An explosion proof lamp

If necessary, a means for hoisting a person out should be provided.

the space is regarded sale to work bv the officer in charge the lollowing arrangements are to be ensured:

1. Access to and within the space well illuminated.

2. No sources of ignition to go in the space, before approved by the responsible officer.

3. Before commencing activities involving heat, Iike welding or cutting, a fuel tank must be thoroughly

dried and cleaned.

4. Continuous ventilation is to take place.

5. The atrn sphere must be tested regularly to ensure safe working conditions.

6. At least one person mUst sttyat the entrance, in constant comrnunicttion with those inside.

7. At the entrance to the space thefollowing equipment must be available:

- A bretthing apparltus

- Spare aircilinders

- A lifeline with harness/belt

- An explosion proof lamp

If necessary, a means for hoisting a person out should be provided.

3 THE USE oi= EQUIPMENT ANO CLOTHING REQUIREO FOR ENTRY INTO

OANGEROUS SPACES

* Breathing apparatus with w separate air supplies.

*

Oxygen meter.

*

Lifelines and harness

*

Stretcher.

* Resuscitator medical oxygen .

4 INSTRUCTIONS ANO ORILLS IN RESCUE FROM ENCLOSEO SPACES

Instructions as done above, drills to be done regulrly.


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Watch Keeper Training Sook

Ship s Constructional Features

Double Bottom Construction

Transverse ffaming

DO

o

Bilge keels

DO

Platellors

Platefloor

Ffam

Framing within the double bottom is to be either

longitudinal or transverse. The framing must be .

longitudinal in ships over 120 m in length and

when the notation 'Heavy Cargoes' is assigned.

In passenger ships the inner bottom plating is to

be continued out to the ship's side in such a

manner as to protect the bottom to the turn of the

bilge (SOLAS requirement). Drainage is effected

by means of wells situated in the wings, having a

capacity not les than 0.17 cubic metres.and

extendingto not nearer thE3sheH than 460 mm. I

Sufficient holes i3.reto I::>ecut in thE3nner bottom

non-vvatertightJnon-oilti~htfloor i3.ndside QirdE3rs

to provide adE3quateventili3.tIonand access: Their

size should. not exceE3050 depth of the double

bottom and they should be circular or eliptical in

shape.

(2) Fire:

(3) Subdivision:

Silge keels are fitted at the turn of the bilge to help damp the rolling motion of the ship. They extend over a portion

of the midship length of the ship and are positioned to minimize drag.

Watertight bulkheads

Transverse watertight bulkheaos which divide a ship into a number of watertight compartments are of great

importance for the following reasons:

(1) Strength: they give large structural support, resist any tendency to deformation

(racking) and assist in sprE3adingthe hull stresses over a large area.

confines conflagration to particular regions.

divides a ship into a number of watertight compartments.

TRANSVERSE

WATERTIGHi

BULKHEAD

End ot,sti~~n_~-uJ lttached

uppor ciackonly

Plata or wate:rtight ~Ibor

/

ulknaad

iJ.:

1

,


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AII ships are to have a collision bulkhead, situated not less than O.05L nor more than O.08L tor cargo ships O.05L

+ 3 m tor passenger ships) trom the tore end ot the load waterline, an after peak bulkhead enclosing the stern tubes

in a watertight compartment and a bulkheadat each end

the machinery space.

AII watertight bulkheads are to extend to the uppermost continuous deck, except tor the after peak bulkhead which

may termnate at the tirst deck above the load waterline provided this deck is made watertight to the stern or to a

watertight transom tloor.

The thickness ot bulkhead plating is greater at the bottom than the top as it depends on the head ot water that the

horizontal strakes ot plating would be subject to it the compartment was tlooded. It also depends on the spacing of

the vertical stiffeners whose sectional modulus increases with unsupported length

span and depth of bulkhead.

The scantlings ot the tore peak bulkhead are greater than those of the other watertight bulkheads.

t

there are openings in watertight bulkheads, watertight doors with suitable framing must be fitted, and additional

stiffening in way ot the doors must be fitted so that strength is the same as that ot the unpierced bulkhead.

Pipes and valves attached directly to the bulkhead plating are to be secured by studs screwed through the plating

or by welding.

ngin rooms

The illustrations show the arrangement through an engine room that is situated amidships and one that is situated

aft.

Aft

Accom.

Machinery

ocommoo lion

The location of the engine room is

dependent on a number of factors such as

the type ot ship, number ot screws, type of

machineryetc. In cargo ships it ranges

between aft and slightly aft of amidships,

whilst in passenger ships there is also a

trend tor the machinery to be ah ot midships.

Tankers and bulk carriers always have the

machineryatt.

The main engine seating is to be integral

with the double bottom structure, the tank

top plating in way of the seating being

substantially increased in.thickness.

Adequate transver ; stiffening is required

throughoutthe double bottom, vvithso lid

plate floor at every trame and additional

side girder to give the necessary support

and strength.

Additional transverse strengthening is to be

provided by means of web frames and

strong beams with suitable pillaring or other

arrangements. The webs are to be spaced

not more than five trame spaces apart and are to have a depth ot at least two and onehalt times the depth of the

normal frame.

Where the machinery is aft the double bottoms are to be transversely tramed. Webs as above are to be fitted

whether the side traming is transverse or longitudinal.

In the machinery spaces two means of escape, one of which may be a watertight door, are to be provided. There

must be two means of communication between the bridge and a engine room or control room.

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Pumps

displacement pumps

centrifugal pumps

axial flow pumps)

Displacement Pumps

The pumping action is achieved by the reduction or increase in volume of a space causing the liquid or gas) to be

physically moved.

pistons, vanes, gears or screws)

se/f prirning

2. will produce the discharge pressure required by the system air compressor)

3. can handIe large amounts of vapour

4. complicated

5. before starting, the suction and discharge valves need to be opened, and no va/ves in the discharge line are to

be left closed relief valve)

entrifugal Pumps

The pump consists of:

a pump housing

a top cover

a pump shaft

an impeller

a bearing bush Iubrication)

a sealing arrangement

The pump housing has a special shape volute).

Liquid enters the impeller, where the velocity increases. In the volute or diffuser most of the kinetic energy is

converted intq pressure.

The shaft seal can be a stuffing box or packed gland most common on Logos2) or a mechanical sea .

not self priming

can be should be) started with c/osed discharge valve.

The simple centrifuga/ pump is used for sea water circulation and other duties where self priming is not a

requirement. When installed for bilge pumping or ballast duty, these pumps require a primer Le. some means of

removing air from the suction pipe so that the liquid to be pumped is caused to flow into the pipe and so to the eye

of the impeller.

Single Stage entrifugal Pump

For general duties the impeller is of aluminium bronze keyed and secured to a stainless steel shaft. The impeller

shown Fig. 1) is fully shrouded and of the single entry type. The renewable wear rings are of aluminium bronze

and the casing is normally of bronze or cast iron. The cover has a hub containing the shaft bearing at the bottom

and, above, either a packed gland or a mechanical sea . The shaft bearing is of phenolic resin asbestos, lubricated

by the liquid being pumped except for pumps operating on high static lift. These have grease lubricated bronze

bearings to ensure adequate lubrication during the priming periodo A spigotted coupling spacer connects the motor

half coupling to the pump shaft. When this is removed, the pump cover, together with the impeller and shaft

assembly can be lifted out of the pump casing for inspection or maintenance.



12/48

Shaft

bearing

Uppc:r wear

nngs

S~cllring

w;lsh~r

Pump shaft

Lowc:r wear

nngs


Coupling spacer

.- 1land

Gland

._______---- pa c k in g

Lubricator

__ Orain

connection

O

ring

Imp~lkr

Single stage centrifugal pump Hnmworthy Engineering Ud)

mp ll rs

The fully shrouded, single entry impeller in the pump shown Pig. 1) is the type most widely used. It consists of a

number of vanes curving backwards from the direction of rotation. The vanes are supported on one side by

shrouding connected to the hubo The shrouding supporting the vanes on the other side, has an entry at the centre.

When the pump is operating, liquid in the casing is swirled by the rotating impeller. The swirling action causes the

liquid to move towards the outside and away from the centre in the same way that stirred coHee moves to the side

of the cup, tending to spill over the rim and leaves a dip at the centre). The backward curving vanes and the

rotation give the liquid a combined radial and circular motion.


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asing

The section of the volute casing shown in the sketch (Pig. 2) increases, thus allowing unrestricted flow from the

impeller. The volute also acts as a diffuser, converting kinetic head into pressure head. Some pumps have a double

volute casing which gives radial balance and reduced wear on the bearings. Pumps designed to produce high

pressure, have a diffuser ring so that a greater quantity of kinetic energy in the liquid can be converted to pressure.

Shroud

;

Yanes

Yolute _/

casIng

Section through impeller and casing

uction

Shroud

Discharge

When a centrifugal pump is operating, the liquid leaving the impeller produces a drop in pressure at the entry or eye

of the impeller. This causes Iquid from the suction pipe to flow into the pump. In turn, there is a movement of the

liquid to be pumped. The latter is normally subject to atmospheric pressure. A centrifugal pump will maintain a

suction ift of four metres or more once it has been primed, beca use of the water passing through. The water in a

pump acts like a piston for water in the suction pipe and an empty pump will not operate. A pump which is required

to initiate suction from a iquid level below itself, must be fitted with an air pump.


2


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Valves

Globe Valves

Valve parts:

valve body with flanges (liquid flow from below)

spindle and valve disc (Ioose or connected)

valve seat

gland with packing

screw ift

screw down non return

I - -.

Gate Valves

Full f10wvalves

Cocks

Used in small-bore pipe work and is joined to adjacent pipe work by a compression coupling

Non Return Valves

Relief Valves

Spring loaded safety valves (used on displacement pumps, air bottles, cylinder heads, fire main line)

Quick Closing Valves

On all fuel valves above tank top level.


3


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Heat xchanQers

Tube oolers

Tube coolers for engine jacket water and lubricating oil cooling are normally circulated with sea water. The sea

water s in contact with the inside of the tubes and the water boxes at the cooler ends. Two pass Bow is shown in

the diagram Fig. below but straight flow is common in small coolers.

ea water out

ea water in

ing and disc baffles

Tubes

Oilout

liding tube plate

Tube cooler with two pass flow Serck

The oil or water being cooled is in contact with the outside of the tubes and the shell of the cooler. Baffles direct the

liquid across the tubes as it flows through the cooler. The baffles also support the tubes.

Tubes of aluminium brass 76 per cent copper; 22 per cent zinc; 2 per cent aluminium are commonly used.

Ordinary brasses and other cheap materials have been used with unsatisfactory results. The successful use of

aluminium brass has apparently depended on the presence of a protective film formed along the tube length by

corrosion of iron in the system. Thus unprotected ron in water boxes and other parts, while itself corroding, has

prolonged tube life. This was made apparent when ste~1 wasreplac~d Oy other corrosian resistant materals or

protected more completely. The remedy in these systems has been to fit sacrificial soft ron or mild steel anodes in

water boxes or to introduce iron in the form of ferrous sulphate fed nto the sea water. The latter treatment consists

of dosing the sea water to a strength of 1 ppm for an hour per day over a few weeks and subsequently to dose

before entering and after leaving port for a short periodo

Early tube falures may be due to pollution in coastal waters or to turbulence in some cases.

Many coolers are fitted with tubes of 70/30 cupro-nickel. More expensve materals are available. Tubes are

expanded nto tube plates and may be further bonded by soldering.

Tube Plates

Naval brass tubeplates are used

with aluminium brass tubes. Tube

stacks are made up to have a

fixed tube plate at one end and a

tube plate at the other end which

is free to move with the

expansion of the tubes Fig.

right . Other materals found in

service are gunmetal, aluminium

bronze and sometimes special alloys.

Detail of cooler expansion arrangement

Tu~s fixed byexpansion


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16/48


eat Exchan~ers

Tube oolers

Tube coolers for engine jacket water and lubricating oil cooling are normally circulated with sea water. The sea

water is in contact with the inside of the tubes and the water boxes at the cooler ends. Two pass Bow is shown i11

the diagram Fig. below but straight flow is common in small coolers.

ea water out

ea water in

ing and disc baffles

Tubes

l

out

liding lube plate

Tube cooler with two pass flow Serck

The oil or water being cooled is in contact with the outside of the tubes and the shell of the cooler. Baffles direct the

liquid across the tubes as it flows through the cooler. The baftles also support the tubes.

Tubes of aluminium brass 76 per cent copper; 22 per cent zinc; 2 per cent aluminium are commonly used.

Ordinary brasses and other cheap materials have been used with unsatisfactory results. The successful use of

aluminium brass has apparently depended on the presence of a protective film formed along the tube length by

corros ion of iron in the system. Thus unprotected iron in water boxes and other parts, while itself corroding, has

prolonged tube life. This was made apparent when ste1 wasreplaced by othercorrosion resistant materials or

protected more c;ompletely. The remedy in thesesystems has been to fitsacrificial soft iron or mildstee1anodes in

water boxes or to introduce iron in the form of ferrous sulphate fed into the sea water. The latter treatment consists

of dosing the sea water to a strength of 1 ppm for an hour per day over a few weeks and subsequently to dose

before entering and after leaving port for a short periodo

Early tube failures may be due to pollution in coastal waters or to turbulence in some cases.

Many coolers are fitted with tubes of 70/30 cupro-nickel. More expensive materials are available. Tubes are

expanded into tube plates and may be further bonded by soldering.

Tube Plates

Naval brass tubeplates are used

with aluminium brass tubes. Tube

stacks are made up to have a

fixed tube plate at one end and a

tube plate at the other end which

is free to move with the

expansion of the tubes Fig.

right . Other materials found in

service are gunmetal, aluminium

bronze and sometimes special alloys.

Detail of cooler expansion arrangement

Tu~s fixed byexpansion


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17/48


Tube Stack

The tube stack shown is fitted with alternate disc and ring baffles. The fixed end tube plate is sandwiched between

the casing and the water box. If the joints leak at the other end the special'tell tale' ring will allow the liquids to

escape without mixing. The joint rings are of synthetic rubber.

Water oxes nd Covers

Easily removable covers on water boxes permit repairs and cleaning to be carried out. The covers and water boxes

are commonly of cast iron or fabricated from mild steel. Where they have been coated with rubber or a bitumastic

type coating, the iron or steel has been protected but has provided no protection for the tubes and tubeplate.

Uncoated ferrous (iron) materials in water boxes provide a protective film on the tubes as the unprotectecl iron itself

corrocle , the products of corrosan coating the tubes. The iron also gives some measure of cathodic protection.

Water boxes of gunmetal nd other materials ar~ LJsedbut these, Iikethe coated ferrous metals, Qive no

protection. Soft iron or mild steel anodes can be fitt~d in the water boxes and provided they cause no turbulence,

will help to give cathodic protecton and a protective film.

Shell

The shell or cylinder is fabricated or casI. It is in contact with the Iiquid being cooled. This may be oil, with which

there is no corros ion problem, or water, which is normally inhibited against corroson. The material is not critical

(provided it is not reactive with any inhibiting chemicals) beca use it is not in contact with sea water.

Sea Water Side

Only the minimum of salt water should be circulated in coolers. Thus it is best to regulate temperature by means of

the salt water outlet valve, the inlet being left full open. If temperature is maintained by adjustment of the oil or

jacket water flow, with full flow on the sea water side, there is a greater corrosion risk.

Strainers on the sea water pump suctions should be cleaned and check~d regularly, as blockage will starve the

syst(3m of water. Damage to the str iner plate will UOWoHds through Which willplock the end of the copler. The

cooler will become ineffective in either case and P rtial blocking of the cooler tencls to lead to erosion d;.mage.

The sea water side should be disturbed only when necessa.ry to avoid damage to the protective film on the inside

of the tubes. If cleaning is needed to remove deposits, use should be made of the special soft brushes. Chemical

c1eaning may be recommended particularly where hard deposits have accumulated. The manufacturers handbook

willlist acceptable cleaning chemicals. For the sea water side of coolers, an acid such as hydrochloric acid may be

the agent.

Precautions are essential when dealing with corrosive chemicals used for cleaning. Gontact is avoided by wearing

gloves and protective goggles or a face shield. Should the chemical come into contact with the skin or the eye, the

best first aid is usually to wash the affected parts immediately with water. If other treatment is necessary this can be

found from the medical book. Before handling any chemical the instructions should be read and the type of first aid

that might be necessary ascertained. There are now such a variety of chemicals in use that reference books are

needed. Mixing instructions must be followed.

Before cleaning, coolers are isolated from the system by valves and blanks or by removing pipes and blanking the

cooler flanges. Flushing is necessary after the cleaning agent has been drained from the cooler.

Plate Tvpe Heat ExchanQer

Plate type heat exchangers were original y developed for the milk industry where daily cleaning is necessary. They

were first used at sea, as coolers, in the nineteen-fifties.

The plates are metal pressings (Fig. next page left), corrugated with horizontal or chevron pattern corrugations.

These make the plates stiffer and therefore permit the use of thinner material. They also increase the heat

exchange area and produce a turbulent flow. Al these factors contribute to the efficiency of heat transfer.


5


18/48


Turbulence, as opposed to smooth tlow, causes more the liquid passing between the plates to come into contact

with them. It also breaks up the boundary layer ot liquid which adheres to the metal and acts as a heat barrier in

smooth tlow. However, the turbulence can cause plate damage due to erosion and materials normally used in tube

coolers tor sea water contact, may not be suitable in plate coolers.

Sea water out

....

Lub oil

in

Lub oil

out

Cooler plate

Sea water in

Plate ccioler assembly

Carrying

bars

Turhulent Ilow

Tell-

taJe

COlTugalion

Nilrite

rubber

joint

Plate material tor sea water contact is titanium. This is an expensive metal but apparently able to withstand the

conditions ot service. Aluminium-brass has been used with poor results. Possibly tailure ot aluminium-brass has

been due to the presence ot organic sulphides and other chemicals in coastal and inland waters. Titanium is

immune trom ths type ot attack.) However, other t tors such as the turbulence in plate coolers or changes in the

materals ot sea water systems may be responsible tor early tailures. Stainless steel has been used in plate coolers

tor duty with sea water, but proved unsuccesstul although it is suitable tor other applications.

The joint material is normally nitrile rubber which is bonded to the plate with suitable adhesive such as Plibond.

Other joint materals tor higher temperatures are available, such as compressed asbestos tibre. The nitrile rubber is

suitable tor temperatures up to about 100C 230F). At high temperatures the rubber hardens and loses its

elasticity. The rubber joints are compressed when the cooler is assembled and the clamping bolts tightened.

Overtghtening can cause damage to the chevron corrugated plates so the cooler stack must be tightened, and

dimensions checked, during the process. Joints must be adequately clamped to prevent leakage.

Allliquid inlets and outlets are at the tixed end plate. The movable end sits in the horizontal carrying bars and the

plates are also located and supported by these. The

tlow

ports at the corners

ot

the plates are arranged so that the

cooling Iiquid and the liqud being cooled pass between alternate pairs ot plates. The sketch Fig. above right)

illustrates the way in which the liquids tlow. Best efficiency is obtained by Iiquids moving in opposite directions Le.

contra-tlow. Joint leakage is visible externally except tor the double joint at the ports on one side ot the plate. A

drain hole acts as a tell-tale tor this section see Fig. above left).


- 16-


19/48


dvantages nd isadvantages

Plate coolers are smaller and Iighter than a tube cooler giving the same performance. No extra space is needed tor

dismantling a tube cooler requires enough clearance at one end to remove the tube nest . Their higher efficiency is

shown by the smaller size. Plates can be added, in pairs, to increase capacity and similarly damaged plates are _

easily removed, it necessary without replacement. Cleaning is simple as is maintenance. Turbulent how heIps to

reduce deposits which would interfere with heat t ow

In comparison with tube coolers, in which tube leaks are easily located and plugged, leaks in plates are sometimes

difficult to tind because the plates cannot be pressurized and inspected with the same ease as tube coolers.

Deteriorating joints arealso a problem; they may be difficult to remove and there are sometimes problems with

bonding new joints. Tube coolers may be preterred tor lubricating oil cooling beca use ot the pressure differential.

Cost is another drawback; there are a large number of expensive joints on plate coolers and the plates are

expensive.


- 17-


20/48


Diesel Enaines

The diesel engine is a type of internal combustion engine which ignites the fue/ by injecting it into hot, high

pressure air in a combustion chamber. In common with al internal combustion engines the diese/ engine operates

with a fixed sequence of events, which may be achieved either in four strokes or two, a stroke being the travel oL

the piston between its extreme points. Each stroke is accomplished in half a revolution of the crankshaft.

Exhaust

valva

Air inlet

ports

----------

Crosshead '

8ottom ehd

belring

- -Exh. lust port

Piston

Connecting rod

~- ..

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