WHEATTRANSPORT & VENTILATION

on M.V. DOLPHIN

VoyageCONSTANTZA (ROMANIA) – ALEXANDRIA (EGYPT)

CONSTANTZA MARITIME UNIVERSITYCONSTANTZA 2012

1. Specifications for cargo

1.1 Cargoes at risk

Cereals as a hygroscopic products have a natural moisture content. They may retain, absorb or release water vapour, and excessive amounts of inherent moisture may lead to signifiant self-heating and “moisture migration” within the cargo resulting in caking, mildew or rot. Examples of hygroscopic products include grain, rice, flour, sugar, cotton, tobacco, cocoa, coffee and tea.

1.1.2 Cargo sweat

Cargo sweat refers to condensation which may form on exposed surfaces of the stow as a consequence of large amounts of warm, moist air being persistently introduced into a hold containing substantially colder cargo.

1.1.3 Ships sweat

Ships sweat refers to condensation which forms directly on a vessel's structure when the air within a hold, made worm and moist by the cargo, comes into contact with cold surfaces as the vessel moves into cooler climates. Cargo may be damaged by overhead drips, by contact with sweat which has formed on the ship's sides or by condensed water which may accumulate at the bottom of the hold.

1.2 Grain cargoes

Grain cargoes are subject to germination, which will depend upon temperature and the presence of moisture.

Through ventilation will therefore be essential.The air between the grains will be saturated with water vapour which can only be

removed by a through current of drier air. Should a sudden fall of temperature take place, then condensation will occur. If care is not taken, the water will lead to germination of the grain, and this will be accompanied by a rise of temperature and evolution of gas.

2. Specifications for vessel

2.1 General description of the ship

The vessel is designed and built as a single screw motor driven bulk carrier for normal worldwide service.

The vessel comply with the requirements for type “B-60” ships defined by the International Convention of Load Lines, 1966.

The vessel is capable to carry grain in bulk or sack, coal, iron ore, steel coil, steel pipe and other dry cargoes. No deck cargo to be loaded.

Certain dangerous goods could be carried inside the cargo holds based on the outfitting and equipments mentioned in specification.

The design of vessel reflect economical operation, safety and environmental protection. The vessel offer the following measures of environmental protection:

✔ NOx emission control;✔ Oil fuel management for the control of SOX emission;✔ Refrigerant management;✔ Oil pollution prevention measures;

✔ Garbage management;✔ Sewage treatment and discharge control;✔ Ballast water management;✔ Prohibit application of hull anti-fouling system containing TBT.

The vessel is designed and built with single continous deck with forecastle.All accommodation including navigation bridge and propulsion machinery are located

aft.All oil tanks with capacity larger than 30m3 is designed not directly contact with shell.The cargo area have five (5) cargo holds. Cargo holds are constructed as single skin

with topside tanks, hopper tanks and double bottom.Four (4) set of 30 t S.W.L. Single deck cranes are arranged as shown on General

Arrangement (see Fig.1).

Fig.1 General Arrangement

2.2 Principal particulars

GENERAL STACK LOAD

Type Bulk Carrier Hold none

MAIN DIMENSIONS Deck / hatch none

Length over all 189.99 m UNIFORM LOAD

Length between perp. 185.00 m Double bottom (hold 1,3,5) 25 t/m3

Breadth moulded 32.26 m Double bottom (hold 2,4) 18 t/m3

Depth to main deck 18.00 m Hatch cover No deck load

Draught, design 11.30 m HOLD CAPACITY

Draught, scantling, freeboard 12.80 m Total 71500 m3

Gross tonnage 32300 GT CARGO HATCHES

Net tonnage 18700 NT Folding type, hydraulically operated

Deadweight on design draught 11.30 m

48000 TDW Hold no. 1 18.86 m x 18.26 m

Deadweight on scantling draught 12.80 m

57000 TDW Hold no. 2,3,4,5 21.32 m x 18.26 m

TANK CPACITIES CARGO DECK CRANES

Heavy fuel oil (100% full) 2200 m3 4 cargo deck cranes, 36 t SWL, 5.0 m / 28.0 m min / max outreach, installed at centre line

Marine diesel oil (100% full) 120 m3 SERVICE

Fresh water (100% full) 400 m3 Service speed (on design draught, 90 % MCR

14.2 kts.

Ballast water (excluding No. 3 hold) (100% full)

15500 m3 Endurance Min. 18000 n.m.

Cargo hold (grain, including hatch coamings)

71500 m3 MAIN ENGINE

CONTAINER CAPACITY Type MAN B&W 6S50MC-C

Total none Rating 9480 kW / 127 r.p.m

Reefer plugs none AUXILIARY EQUIPMENT

Diesel generator 3 x 600 kW / 900 r.p.m.

Emergency generator 1 x 99 kW / 1800 r.p.m

Shaft generator none

Bow thruster none

2.3 Prepare the holds for carring wheat

2.3.1 Hold cleaning

Prior to high pressure hold washing, excess cargo residue on the tank top should will be removed by hand sweeping and lifted out of the holds via the use of a portable mucking winch. A good working relationship with the stevedores at the discharge port may help to expedite this operation.

After all excessive cargo residue has been removed then the holds can be washed with salt water using a high-pressure hold cleaning gun. Ship are fitted with fixed hold cleaning equipment, under the hatchcovers. A flexible high-pressure hose is connected between a flange on the hatchcover and the deck high-pressure hold washing line.

Fig.2 Flaking paintwork under the hatch coaming can result in a hold failing the grain survey.

All cargo residues washed down will be removed via the hold eductors or mucking winch. Special attention would be given to cargo residue wedged behind pipe brackets, hold ladders, and on the under-deck girders and transversals. Special attention should be paid to ventilators to ensure that remnants of previous cargo have been removed and the area is grain clean. Bilge suctions must be tested both before and after washing and the results entered in the cargo notebook and/or deck log book.

2.3.2 Fresh water rise

The final stage of hold washing is the fresh water rinse. The fresh water will be pumped into the fire main via GPS to prepare holds for wheat. Prior to commencing the fresh water rinse, the fire line is flushed through with the after peak fresh water to remove all traces

of salt water. Once the fire main is clear of salt, all deck fire hydrants and anchor washer should be sighted and confirmed that they are closed.

On completion of the hold fresh water rinse, all hatch entrances, hatch trunking and hand ladders should be hand washed and fresh water rinsed using the fresh water high-pressure gun.

2.3.3 Holds drying

To prevent possible condensation in the hold, all the recessed hold eductors must be drained of any water residue, be clean dry and odourless. When the eductor is empty the drain plug must be replaced and secured. The eductor hold plate must be secured with all the securing bolts and duct tape should be used to cover both the securing bolts and recessed lid handles.

Hold bilges should be completely dried out, odourless and in a fully operating condition. The surveyor will usually require to sight one bilge in each hold to ensure that they have been cleaned out correctly.

Top tank must be completely dry and any indentations on the tank must be wiped dry. The hold should be completely odourless, by maximising hold ventilation. Duct tape is used to cover the small gap between the bilge strainer and tank top. The hold hydrant area should be cleaned and dried out. The steel cover refitted and secured in place with all its bolts/screws.

2.3.4 Grain inspection

Prior to the grain inspection all hatches and access lids must be open and safely secured with all locking pins/bars. All hatches should be checked for loose scale or flaking paint. If weather conditions permit during the day, the holds should be opened to allow fresh air to assist the hold drying process. All small pools of water should be mopped dry. All hatch rubbers and center line seals should be wiped over with a clean dry rag to confirm their cleanliness. Fig.3 Hold that is grain clean and ready for

inspection and load.

2.3.5 Loading wheat

Hatches not being loaded will be kept closed. All hatches after passing the grain inspection and prior to load, must be inspected on a daily basis to ensure that they are still completely dry. Hatches containing wheat cargo must not be entered due to a possible lack of oxigen. During the load, it is important to keep the wheat cargo dry. If the wheat is allowed to become wet, high cargo claims will result. Regular visual check by ships staff throughout the load should ensure that the wheat being loaded is not in a wet condition. These inspections will be recorded in the deck log book.

Fig.4 Loading wheat

3. Specifications for route

ROUTE CONSTANTZA (ROMANIA) – ALEXANDRIA (EGYPT)

Port of loading CONSTANTZA (ROMANIA)

Destination ALEXANDRIA (EGYPT)

Distance between ports 910 n.m.

Average speed 13.5 knts

ETD

ETA

3.1 Carriage of grain safe procedure

One of the most difficult and dangerous cargoes to carry in bulk are grain cargoes. Most grains have an angle of repose (slip angle) of about 20º from the horizontal, which means that if the ship rolls more than 20º the cargo will shift. Then this happens the ship will develop a large list, lying on her side and still rolling will obviously cause a greater shift of cargo which in turn will capsize the vessel.

Because grain cargoes are liable to shift, heavy emphasis is placed on the stability of ships that carry them. The main reason is the variation in the types of grain, including its size and its ability to develop a free flow state when loaded in bulk. Ship carrying grain has to provide grain specific stability information, including grain heeling moments, to the terminal. This section looks at various problems, methods and precautions that must be taken when carrying grain cargoes.

The bulk carriers grain loading manual contains Volumetric Heeling Moments (VHM), which are values based on an assumed surface grain shift of 15° (for a full compartment) and 25° (for a partially full compartment).

1. To avoid shifting of cargo, the grain surfaces must be reasonably trimmed:a) Filled compartment, trimmed the cargo should be trimmed so that all spaces under deck and hatch covers are filled to the fullest extent possible.

b) Filled compartment, untrimmed the cargo should be trimmed within the hatchway but may be left at its natural angle of repose on the surrounding area of the hatchway. The same can be applied for a filled compartment, trimmed if:

• dispensation is granted from trimming by the authority issuing the Document of Authorisation on the basis that the cargo can flow freely to underdeck empty areas through feeder ducts, perforated decks, etc, or

• The compartment is designated a `Specially Suitable Compartment', in which case exemption may be granted from trimming the compartment ends.

2. If the cargo is stowed only in the lower compartment, the lower compartment hatch covers should be secured in the approved manner.

3. If the cargo is stowed in the upper compartment above a tween deck whose covers are not grain- tight, the covers should be made grain-tight using sealing tape, tarpaulins or separation cloths.

4. In partly filled compartments, the surface of bulk grain should be secured by over-stowing except in cases where heeling moments due to grain shift have been calculated and taken into consideration for stability of the vessel.

5. Longitudinal divisions may be fitted to reduce heeling moments due to shift of grain in filled compartments, trimmed, filled compartments, untrimmed and partly filled

compartments, provided that each division:

a. Is made grain-tight.b. Is constructed according to the Grain Code standards.c. Extends from deck to deck in tweendecks.d. Extends downwards from the underside of the hatch covers.

6. The Master shall ensure that the ship:

a. Before loading, can comply with intact stability criteria at all stages of the voyage.b. Is upright before proceeding to sea.c. Has all the paperwork completed and onboard.

4. Wheat ventilation on board

Ventilation of cargo will be done according with DEWPOINT RULE. This means:✔ VENTILATE if the DEWPOINT of the air inside the hold is higher than the

DEWPOINT of the air outside the hold.✔ DO NOT VENTILATE if the DEWPOINT of the air inside the hold is lower

than the DEWPOINT of the air outside the hold.

4.1 Measurement of temperature.

Ventilation records are crucial. In the event of moisture damage, evidence showing that the vessel ventilated correctly may be instrumental in defending any ensuing claims.

Because the DEW POINT RULE has been followed, wet and dry bulb temperatures and dew points should be logged once per watch, bearing in mind that these may change considerably over a short period. For the same reason, the sea temperature will be also noted.

Fig.5 Measurement of temperature into holdThe dew point of the atmosphere can be ascertained by use of the wet and dry

thermometers in the Stevenson Screen on the windward bridge wing and reference to a dew point table.Entry to the holds should be undertaken in line with the requirements of the vessel Safety Management System with safe enclosed space entry procedures usd as necessary.

4.2 Determination of DEW POINT temperature.

In accordance with good seamanship, if it is necessary will use Table 29. Conversion Table for Thermometer Scales (see Annex 1) – will enter in this table with temperature Fahrenheit (F); Celsius (C) or Kelvin (K) and take out the corresponding readings on the other two temperatures scales.

Therefore, the formulas are:

Determination of RELATIVE HUMIDITY will be made using Table 35. Relative Humidity (see Annex 2) – with the dry-bulb (air) temperature (F), and the difference between the dry-bulb and wet-bulb temperatures (F). The value taken from the table is the approximate percentage of relative humidity. If the dry-bulb and wet-bulb temperatures are the same, relative humidity is 100%.

Determination of DEW POINT will be made using Table 36. Dew Point (see Annex 3) – with the dry-bulb (air) temperature (F), and the difference between the dry-bulb and wet-bulb temperatures (F). The value taken from the table is the dew point in degrees Fahrenheit. If the dry-bulb and wet-bulb temperatures are the same, the air is at or below the dew point. Fig.5 Dry-bulb & Wet-bulb (psychrometer)

This information will be recorded (see Annex 4) for each hold together with the times of commencing, ceasing or resuming ventilation, and the reasons for doing so.

4.2 Wheat ventilation

The decision on whether or not to ventilate will require careful consideration by the Master and officer. The basic principle is to keep the dew point of the air within the hold below the temperature of the hold structure and the cargo to stop the formation of ship and cargo sweat. According to the DEW POINT Rule wheat ventilation will be done or not for each hold and recorded into Annex 4, column “Ventilate”. Column “General Remarks” is dedicated for any comments regarding column “Ventilate”.

5. Conclusion

It should be noted that requirements for the transport of grain are covered by the separate code called International Code for the safe Carriage of Grain in Bulk (International Grain Code) as grain has the highest shifting hazard.

6. Annexes

6.2 Annex 1 – Table 29. Conversion Table for Thermometer Scales6.1 Annex 2 – Table 35. Relative Humidity6.2 Annex 3 – Table 36. Dew Point6.2 Annex 4 – Temperature and Ventilation Log

7. Bibliography

UK P&I Club, Thomas Miller P&I Ltd. Carefully to carry, 2002 Edition

David Anderson, Daniel Sheard and North of England P&I Association

Cargo ventilation – A guide to good practice, 2006 Edition

International Maritime Organization, London International Code for the safe Carriage of Grain in Bulk (International Grain Code), 1991 Edition

West of England Insurance Services (Luxembourg) S.A.

Loss Prevention Bulletin, LPB 005

Steamship Mutual Loss Prevention Bulletins by Ship Safety Trust

RA06 – December 2009

Nathaniel Bowditch, LL.D. The American Practical Navigator, 2002 Edition