Part B – Paper 1 – General Ship Knowledge (3 hrs, 50% pass)
Function (2): Cargo handling and stowage at the operational level
Competence: Monitor the loading, stowage, securing, care during the voyage and the unloading of cargoes Inspect and report defects and damages to cargo spaces, hatch covers and ballast tanks
Criteria: Cargo operations are carried out in accordance with the cargo plan or other document and established safety rules and regulations, equipment operating instructions and shipboard stowage limitations. The handling of dangerous, hazardous and harmful cargoes complies with international regulations and recognized standards and codes of safe practice. Communications are clear, understood and consistently successful. The inspections are carried out in accordance with laid down procedures and defects and damages are detected and properly reported.
Cargo handling and stowage 1. Cargo handling, stowage & securing. i. 2. Knowledge of the effect of cargo including heavy lifts on the seaworthiness and stability of the ship. i. When loading due regard must be had for the vessel’s stability. The cargo should be so distributed that there is a reasonable GM on completion of loading. 3. Knowledge of safe handling, stowage and securing of cargoes including solid bulk cargoes and dangerous, hazardous and harmful cargoes and their effect on the safety of life and of the ship. i. Refer to IMDG Code 4. Ability to establish and maintain effective communications during loading and unloading. i. 5. Definitions of the various terms used in the carriage of goods, i.e. bale capacity, grain capacity, stowage factors, broken stowage, measurement cargoes, deadweight cargoes. i. Bale capacity – cubic capacity of a space when the breadth is taken from the inside of the cargo battens, the depth from the wood ceiling to the underside of the deck beams and the length from the inside of the bulkhead stiffeners. ii. Grain capacity – cubic capacity of a space when the lengths, breadths and depths are taken right to the plating. An allowance is made for the volume occupied by frames and beams. iii. Stowage factors – the volume occupied by unit weight of cargo. Usually expressed as cubic meters per tonne. It does not take into account any space which may be lost due to broken stowage. iv. Broken stowage – it is the space between packages which remains unfilled. The percentage that has to be allowed varies with the type of cargo and with the shape of the hold. It is greatest when large cases have to be stowed in an end hold v. Measurement cargoes – cargo on which freight is usually charged on the volume occupied by the cargo and this cargo is usually light, bulky cargo stowing at more than 1.2m3/tonne but may also be heavy castings of an awkward shape where a lot of space is occupied. vi. Deadweight cargoes – cargo on which freight is charged on its weight. Cargo stowing at less than 1.2m3/tonne is likely to be rated as deadweight cargoes. 6. Cargo handling equipment. The meaning of Safe Working Load. The correct rigging and safe operation of derricks, cranes, and stores hoists, etc. Cargo Handling Equipment: i. Union purchase 1. A speedy method of working cargo. 2. It should not be used for loads in excess of 2.55 tonnes or 1/3 of the SWL of the lowest rated derrick used, whichever is the least. 3. 2 derricks are used, one being positioned so as to plumb 使垂直 the hatch and the other to plumb overside. 4. The runners of the 2 derricks are joined by a union hook. 5. Schooner guy is fixed between 2 derricks to avoid them splaying apart as they rise. 2 derricks should be topped together 6. The 2 derricks are held in position by slewing guys. So the derricks do not move during operation. Only 2 cargo runners move. Preventer guys should be fitted in addition to slewing guys, passing over the derrick head once the derricks have been floated from crutches. 7. The derrick which plumbs the load first takes the weight and when the load has been lifted above gunwale height, the weight is gradually transferred to the second derrick. 8. When the second derrick has all the weight, its fall should be slacked away until the load is landed in the desired position. 9. It should be noted that if the angle between falls is 120 degree and the load is midway between the derricks, the tension on each fall is approximately equal to the weight lifted. This angle should not be exceeded. 10. When a load is suspended between 2 derricks, there is a considerable side-ways pull on each. This tends to bring the 2 derricks heads together, and for this reason, a preventer guy should always be rigged to back up the outboard guy on each derrick ii. Swing derrick 1. Suitable for dealing with heavier lifts than the union purchase 2. The derrick may be swung to plumb the desired position 3. A deadman may be used instead of a winch to operate one of the guys. 4. This consists of a weight which is positioned on the offshore side of a vessel. 5. The derrick may then be swung in one direction by a guy led to a winch and in the other by the dropping of the deadman. iii. Single whip 1. Used in conjunction with a bull rope for discharging light cargoes. iv. Heavy lift derrick / Jumbo derrick 1. Check the vessel is upright and on even keel 2. Clear away other rigging in the way of operation 3. Clear away canvas covers 4. Rig preventer backstays to the mast 5. Ensure the topping lift in good condition, securely shackled 6. Engage 2 winches - port and starboard power guys. Check the leads and moving blocks clear 7. Engage 2 winches – lifting purchase and topping lifting 8. Pass wire messenger about the derrick head and remove the clamp holding the derrick to the mast 9. Lower derrick to secure lifting purchase. 10. Check all winches are in double gear and all rigging is secured Safe Working Load i. Breaking strength divided by the safety coefficient Safe Handling Practice for derricks i. Derrick rigging should be regularly maintained with plan. Visually check before use ii. Before raise, lower and adjust a derrick, the hauling part of the topping life should be flaked down the deck clear of the operational area. All persons should stand clear iii. When topping lifts are secured to bitts, 3 complete turns should be taken before the 4 cross turns on top. Place a light lashing to prevent spring off of the wire. iv. When the rig is to be changed, the derrick head should be lowered to the crutch or to deck level for safety v. The pawl of winch should be lifted to allow the derrick to be lowered. Seaman should pay attention when performing this duty and ready to release the pawl. vi. Winch driver should take instructions from a single controller with a clear view of operation. The winch speed should be in consistent with the safe handling of the guys vii. Cargo runners should be secured to winch barrels by U bolts and minimum 3 turns should remain on the barrel when fully extended. viii. When dragging heavy cargo from tween deck, the runner should be used direct from the heel block via snatch blocks Safe Handling Practice for Union Purchase Rig i. Safe working angle between married cargo runners should not exceed 90 degrees to avoid excessive tension ii. Cargo sling should be kept as short as possible to clear the hatch coaming iii. Derrick should be topped as high as possible iv. Derrick should be marked with the SWL when rigged for union purchase. Otherwise, the SWL should not be more than 1/3 of single derrick v. Preventer guys of adequate strength should be rigged on the outboard side of each derrick, and secured to the deck with similar tension with slewing guys but to different eyes. Safe Handling Practice for heavy lift (jumbo) derrick 1. Officer to check the lift can be carried out safely and successfully. Ensure SWL of derrick adequate. Grease if need. 2. Give warning of expected list of ship to crew 3. Gangway lift clear of quayside, fore and aft moorings tended, ensure no damage will be incurred by heeling 4. Stability should be checked, concern the free surface effect, rise of G should not render unstable 5. Cast off any barge alongside our ship 6. Examine all rigging by officer. Secure all preventer backstays to the supporting mast. Use correct slings on the load with beam spreaders. Secure steadying lines on the 4 corners of the load to control oscillations during lifting 7. Rig and test steam guys and power guys to ensure correct leads. Winches should all be in double gear 8. Check the lugs on the load. Check the crate/container of the load is reinforced 9. All non-essential person clear away 10. Check no obstruction but enough dunnage on place to land 11. Rid fender as necessary 12. Take weight slowly then stop and inspect all round before proceed. 13. The ship may return sharply after landing the load. The offshore guy could be ease out as the load lands and lifting purchase veer smartly. Winch driver should be competent and under control of single person
7. Types of hatch covers in general use and their safe opening, closing, sealing and securing. Tank lids, trunkway doors, ventilation systems, hatches and other openings to cargo spaces. i. 8. The stowage of general and mixed or unitized types of cargoes in general cargo ships. The making and use of cargo plans. Preparation of holds. Use of dunnage. Separation of cargoes. Loading and discharging processes and the securing of different types of cargo including heavy items. How to prevent or minimize cargo damage due to sweat and pilferage. i. Cargo plans 1. A cargo plan can help to prevent over-carrying, help the stevedores at the port of discharge ii. Preparation of holds 1. iii. Use of Dunnage 1. Ship side – spar ceiling/cargo battens. It consist of timber fit over the side frames horizontally into cleats on the frames. It may also be fit on the bulkheads at the end of the compartment 2. Tank top – covered with a double layer of dunnage to ensure free drainage to the bilges. 3. Tween deck – care to have a layer of dunnage at ship side over the stringer plate since water tends to accumulated there 4. Top of cargo – protected by covering by matting, wood dunnage. iv. Separation of Cargo 1. Method depends on type of cargo ← Instance-bagged cargo – by separation cloths made of burlap ← Steel rails – by chalk marks, water paint or strands of wire ← Bulk cargo – by old tarpaulins or separation cloths ← Bales – by rope yarns ← Timber – by water paints 2. Use polythene sheeting in various colour to separated cargo for different ports 3. Avoid mixing cargo by adequate vertical or horizontal separation 4. When cargo is packed in large containers, separation of small quantity is obviated and effort of handling can be reduced. v. Loading and discharging processes 1. vi. Securing of cargo 1. vii. Sweat 1. Sweat is formed when the water vapour in the air condenses out into water droplets when the air is cooled below its dew point. ← The water droplets may be deposited onto ship’s structure, it is known as “ship sweat” and this may run down onto the cargo. ← The water droplets may be deposited onto the cargo, it is known as “cargo sweat”. It occurs when the cargo is cold and the incoming air is warm. 2. Prevention ← Take the dry and wet bulb temperature of cargo compartments frequently. ← If temperature of outside air is lower than dew point of the air in cargo hold, ship sweat occur (voyage from warm to cold place). ← If temperature of air in cargo hold lower than the incoming air, cargo sweat occur (voyage from cold to warm place). For this case, ventilation from outside air should be stopped viii. Prevent Pilferage 1. Cargo to be loaded into a lock-up, or overstowed quickly if in an open hold 2. Good lighting provided at night. 3. Provide watchman. Also, officer to visit the cargo space frequently 4. Cover ventilators by wire mesh 5. Check hatches are properly closed and locked after work finished for that hold 9. The stowage of dry cargoes in bulk carriers. Loading and discharging methods. Actions to be taken in the case of grab damage. The preparation of holds for the more common types of bulk cargoes. The principal hazards to ship and crew associated with the carriage of solid bulk cargoes, and how the effects of these may be minimized. i. Loading and discharging methods 1. Loading ← Usually loaded from a spout or a tip. The bulk is directed into the required part of the vessel but even so a certain amount of trimming is necessary with most cargoes. At some ports an endless bucket system is used for loading coal and ores, this reduces breakage. At others bulk grain is loaded by bleeding bags into the hold. ← Bulldozers are frequently put into vessel to trim the bulk to the square of the hatch so that the grabs may be continuously used to capacity ← Complete loading in a good trim with minimum shifting. Load no.2 hold - 1/3, then no.3 hold - 1/3, and so on for remaining aft holds. Then load 1/2 in no.1 hold. Then fill up No.2 and aft holds. Then lastly no.1 hold ← Cargo will need to be trimmed as its angle of repose is high, especially large coal is loaded 2. Discharge is done by grabs or elevators. At some ports, bulk will be shoveled into large buckets which are then lifted ashore by the ship’s gear ii. Action for grab damage iii. Preparation of holds 1. Holds and tween decks thoroughly swept down. 2. All dunnage removed from cargo spaces or stowed at one end and covered. Spar ceiling need only be removed if coal, sugar or salt is to be carried 3. Bilges should be cleaned and sweetened, bilge suction test. Tween deck scuppers should be covered with burlap and cement 4. Cement chocks at the top of the bilge and tween decks should be examined and found or placed in good conditions 5. Limber boards should be covered with separation cloths or old tarpaulins so as to prevent the bulk getting into the bilges 6. All hatch beams should be in position. The condition of hatch boards and tarpaulins should be checked. 7. Shifting boards should be rigged where required 8. Fire extinguishing arrangement tested. The most effective way of dealing with a coal fire is by dousing 弄熄 it with water from the top. It is often possible to dig down to the seat of a coal fire. iv. Principle hazards 1. Coal is very liable to spontaneous heating. If there is sufficient oxygen available, combustion is liable to take place. Freshly mined coal absorbs oxygen with extrinsic moisture, and forms peroxides. This in turn breaks down to form carbon monoxide and carbon dioxide. Heat is produced by this reaction causing further oxidation and further heat. If this heat is not dissipated, ignition will occur. v. Minimize hazards 1. Ventilation takes heat from the coal but it also allow unwanted oxygen into the coal 2. Stow coal away from hot bulkheads to keep coal cool 3. Allow only surface ventilation to keep oxygen away from coal. 4. Remove spar ceiling and cargo battening to avoid them to give air pockets in the coal 5. For the first 5 days after loading, the ventilators should be utilized for removing gas, then the ventilators to the lower holds should be plugged except for about 6 hours every 2 days 6. The iron deck of ships carrying coal in the tropics can be covered with dunnage to lessen heating 7. The temperature of the coal at three heights should be taken daily. The temperature tubes should have closed ends to prevent admissiono of air into the cargo. 8. Naked lights should not be used in holds or other spaces in which gas may accumulate until the spaces are well ventilated 9. Make full use of breathing apparatus or smoke helmet and safety lamp. 10. Avoid chipping and painting below decks. No smoking, and oily waste, wood, old rope should not left below to be ignited by heat 11. On arrival at discharging port, the hold ventilators should be unplugged and the lower hold well ventilated before commencing to work cargo
10. The handling, stowage, securing and carriage of deck cargoes. i. Vessel must have adequate stability at all stages of the voyage for the amount of cargo which it is proposed to load. Bear in mind that some cargoes such as timber can absorb up to 1/3 of their own weight of water. Loss of weight due to consumption of water, fuel and store must be considered. Upsetting moments caused by wind must be taken into account. ii. Adequate provision must be made for the safety of the crew when passing from one part of the vessel to another. When carrying deck cargo which prevents access for the crew to their quarters along or under the deck, a walkway has to be provided over the cargo with suitable dimensions. iii. Steering arrangements must be effectively protected from damage and in the event of a breakdown in the main steering arrangements an emergency gear must be capable of being rigged and operated. iv. Where the cargo is stowed on the hatches, these are to be properly battened down and of sufficient strength to take the intended cargo v. The decks are to be of sufficient strength for the intended cargo and if necessary they should be strengthened by tomming or shoring underneath. vi. The deck cargo is to be well secured and if necessary, protected from the weather and from the heat of the sun. It must not be so high as to interfere with the navigation of the ship.
11. Containerized and Ro-Ro cargoes. Methods of handling and securing in fully specialized or partly conventional ships. Principal hazards to be avoided during loading, carriage and discharge. Checks to be made to ensure correct out-turn. Main container types. Stowage of containers on deck of ships which are not specially designed and fitted for the purpose of carrying containers i. Should be stowed in the fore-and-aft direction ii. Should not extend over the ship’s sides. Adequate support should be provided when containers overhang hatches or deck structures iii. Should be stowed and secured so as to permit safe access for personnel iv. Should at no time overstress the deck or hatches on which they are stowed v. Bottom-tier containers should be stowed on timber of sufficient thickness to transfer the stack load evenly on to the structure of area vi. Use locking devices or cones between containers when stacking vii. Take into consideration of position and strength of securing points Securing of container on non-container ships i. Secure to protect them from sliding and tipping. Hatch covers carrying containers should be secured to the ship ii. Lashing consist of wire ropes or chains with enough strength and elongation ability iii. Timber shoring should not exceed 2 m in length iv. Wire clips should be adequately greased and tightened v. Lashing should be kept under equal tension
12. Liquid cargoes. Loading and discharging processes in tankers and OBO's. The hazards associated with petroleum, liquefied gases and bulk chemical cargoes and general safety precautions and measures. Gas testing instruments. Gauging and venting systems. Cargo pipeline systems. Tank cleaning and gas freeing processes.
13. Salt water ballast. The requirement to ballast in light ship condition. The control of ballast operations simultaneously with loading and discharging. Filling, discharging and stripping methods. Reasons for the avoidance of overflowing ballast on deck. The hazards of excessive free surface or stress produced by the combination of ballast and cargo operations. Checks to be made on the integrity of ballast tanks.
Defects and damages to cargo spaces, hatch covers and ballast tanks
14. Knowledge and ability to explain where to look for damages and defects most commonly encountered due to loading and unloading operations, corrosion and severe weather conditions. Ability to state which parts of the ship shall be inspected each time in order to cover all parts within a given period of time.
15. Identify those elements of the ship structure which are critical to the safety of the ship. State the causes of corrosion in cargo spaces and ballast tanks and how corrosion can be identified and prevented.
16. Knowledge of procedures on how the inspections shall be carried out. Ability to explain how to ensure reliable detection of defects and damages. Understanding of the purpose of the “Enhanced Survey Programme”.
Past Questions:
1990, 1993, 1995
1. State the general requirement which must be complied with when any cargo is carried on deck.
Q.6 (see Shipboard Operation, second edition, H I Lavery, P.239-240)
1990
2. Describe how inerted tanks are cleaned and made gas free in a VLCC prior to drydocking.
• When it is desired to gas free a tank after washing the concentration of hydrocarbon vapour should be reduced by purging the inerted cargo tank with I.G • Purge pipes/ vents should be opened to atmosphere and inert gas introduced into tank until hydrocarbon vapour concentration reduced to 2% • Gas freeing may be effected by pneumatically, hydraulically or steam-driven portable blower or by fixed equipment, such tank should be isolated to avoid IG to be entered from IG main. • Gas free should continue until the entire tank has an O2 content of 21% by volume and a reading of less than 1% of lower flammable limit is obtained on a combustible gas indicator • Care must be taken to prevent the leakage of air into inerted tank or of inert gas into tank which are being gas-freed. • The tanks will be cleaned by fixed/ portable machines connected to long hose that are fed with washing agent from tank cleaning main on deck • The washing agent could be cold/ warm water or crude oil. • The first tank to be washed will be the one required for clean ballast once they are completed, clean ballast will be loaded whilst the dirty ballast loaded at the discharge port will be discharged with monitoring system. • The washing agent will be stored in slop tank
(see also Shipboard Operation, second edition, H I Lavery, P. 196-198)
2. Describe briefly the preparations and precautions required when stowing the following cargoes. i) iron railway lines ii) bulk salt iii) steel coils iv) rolls of newsprint v) cases of whisky.
Q.8
(i) • Prevent its movement during the voyage • Avoid an unduly stiff ship which would finally resulted to ship damage • Considerable heavy wood dunnage will be required to build a floor on which, to stow the rail • For loading in lower hold, successive tier interlocked and the first 3 or 4 tier showed flat with the remaining tier in grating fashion • To increase the centre of gravity of the ship, some rail should stow on tween deck or underdeck. • Heavy plank should be arranged at the bulkhead to avoid damage and also avoid them from moving forward and aft direction. During pitching, whilst chocking with timber at the sides of the compartment • Provide efficient chain and wire lashing whilst lengths of old rope laid between tier help to provide compact stow • Tomming from deck head beam or stowed on top heavy cases may also prevent movement
(ii) • lime wash the hold before loading, dry up and vent thoroughly • salt is subjected to evaporation and loss weight by 5%, so keep it clear from those dry cargo liable to take harm from moisture • neither should salt be stowed near to wet or moist good • do not stow in insulated compartment or refrigerated container • spillage should be removed immediately when discharging so as to avoid corrosion on ship hull • dry up the bilge well and keep clean • cargo hold shall be free from moisture sources, ventilation may be required during the voyage as required.
(iii) • they shall be stowed in regular tier from side to side of the vessel, making full use of pillars, stanchion and centerline bulkhead • stow the coils on the round, each coil hard up against its neighbors, with wedges of dunnage driven well home under the round • small timber should be available to block off and secure a solid stow, as it settle
(iv) • stowed solid and well chocked off to avoid movement • handle with soft rope slings over which rubber tubing is fitted to avoid tearing the paper • handle by fork lift trucks equipped with clamps • cargo hooks, crow or pinch bar prohibited
(v) • extra care to avoid pilferage • when receiving, keep sharp lookout and check for damage • any case that doubt to have been abstracted ashore should be rejected • special cargo locker should be made use • IMDG code shall be observed (see Thomas’ Stowage for full details)
1991, 1997
3. (a) State the advantages and disadvantages of a union purchase derrick system. (b) State, with reasons, (i) the minimum topping angle of a derrick (ii) the maximum angle between the cargo runners in a union purchase system.
(a)
Advantages:
1. Fast and efficient method of loading and discharging cargo;
2. Easy to handle by one man as there are only two moving parts two cargo runner;
3. Cargo can be discharged from cargo hold to shore by only one movement.
4. Cargo movement is under more control, less swinging movement, less damage
Disadvantages:
1. Reduced cargo handling capacity (1/3 of the SWL of smaller derrick)
2. Complicated derrick rigging arrangement and process;
3. The winch-men must be highly skilled and experienced.
4. Re-positioning the derricks is time-consuming.
(b)(i) the minimum operating angle of either derrick should be not less than 15deg to the horizontal, and it is recommended that the angle be not less than 30deg.
(b)(ii) the maximum included angle between the cargo runners should not normally exceed 90ﾟ and never exceed 120ﾟ. This is to avoid excessive tension in the rig.
1991, 1997
8. List all the information that should be contained in a cargo plan.
Cargo Plan: 1. Showing the disposition of cargo throughout the vessel on a generous scale, not necessarily exactly to scale, to indicate the comparative volume and size of different parcel in any compartment. 2. All pillar, beam, lockers and position of doors should be should and it is good practice to indicate number and type of derricks/ cranes of each hatch and length and breadth of hatch. The position of cargos parcel should be shown accurately in relation to these features. 3. Suitable details should be advised: whether cargo is on pallets; whether showed by fork lift trucks an whether or not pre-sling. 4. separation methods to be used in case that 2 or more types of cargoes loaded in the same hold 5. any attention have to be drawn by the OOW in respect to the cargo feature, requirement, special inspection of condition, sample test or hold restriction, lifting gear failure/ limitation 6. Cargo handling method to be specified. 7. hazards associated with cargo to be loaded/ discharge and any precaution/ preparation to be taken 8. cargo dimension, quantity, weight, lashing points, characteristics, precautions 9. IMDG stowage and segregation requirements;
10. loading/ discharging sequence;
11. loading/ discharging ports
12. ballast/ deballast sequence or plan;
13. expected draught at various stage of cargo work,
14. cargo lashing/ securing requirement;
9. While loading crude oil in VLCC and overflow occurs. State the actions that should be taken by the officer on watch.
1. raise alarm
2. stop all cargo operation by informing the shore connector and close appropriate valves
3. prevent spillage overboard by, if necessary, adjust trim by changing ballast pattern; and ensure scupper plugs tightened
4. prevent fire and explosion by stopping air intake into accommodation and engine room; ban all smoking; and man fire station on deck.
5. remove fuel from deck by starting air driven pumps for transfer of spilled fuel; by retain suitable ship’s trim; or by transfer spilled fuel into other cargo tank
6. restrict the spread of spillage on the water surface. The use of some form of barrier, if available and appropriate to the prevailing weather condition, may serve to reduce the oil spread
7. report should be made to appropriate port authority. All relevant information about the incident should be advised as well
8. close all access doors and shut down vent system
9. consult SOPEP
10. clean up deck by mop up non-pumpable remainders with loose absorbent; or collect remainder/ absorbent in plastic bags for disposal by contractors
11. lower the level of “save-all”
1992
3. (a) Define : (i) broken stowage (ii) measurement cargo (iii) deadweight cargo b) A hold of capacity 1992 m3 has to be completely filled with 1212 tonnes of bales of jute and bales of gunnies. The bales of jute measure 100cm x 50cm x 60cm and weigh 180 Kg each. The bales of gunnies measure 100cm x 50cm x 80cm and weigh 250 Kg each.
Calculate the number of bales of each commodity that have to be loaded to completely fill the hold with the required weight.
Q. 3(a) Broken stowage – the amount of unused space due to the irregularity of shape of the cargo or cargo space, or the incapacity to stow other cargo over the top. It is expressed as a percentage of total space available.
Measurement cargo – cargo on which freight is charged by space. It usually occupies more than 1 cubic metre f space per tonne weight.
Deadweight cargo – cargo that occupies less than 1 cubic metre per tonne weight. Freight is usually payable on weight.
(b) Jute volume = 1.0 x 0.5 x 0.6 = 0.3 cub. metre
Gunnies volume = 1.0 x 0.5 x 0.8 = 0.4 cub. metre
Let a and b be the amount of bales of jute and gunnies to be loaded respectively
1995
B9. (a) Define (i) Stowage factor (ii) Broken stowage (b) Differentiate between measurement cargoes and deadweight cargoes.
Q. B9 Stowage factor - the number of cubic metre occupied by one tonne of cargo.
Broken stowage – the amount of unused space due to the irregularity of shape of the cargo or cargo space, or the inability to stow other cargo over the top. It is expressed as a percentage of total space available.
Deadweight cargo – cargo that occupies less than 1 sq. metre per tonne weight. Freight is usually payable on weight.
Measurement cargo – cargo on which freight is charged by space. It is usually occupied more than 1 cubic metre of space per tonne weight.
1992
8. Your ship has just completed discharge of a coal cargo. Describe how you would prepare the holds to load a full cargo of grain.
■ cargo hold must be properly cleaned and preparated and all compartments, including sides, stringers, pockets, brackets, etc, must be clean, swept, well ventilated and dried. ■ Rust and scale which might contaminate the cargo must be removed, paint and lime wash may be applied as appropriate to avoid the direct contact of scaled ship side with the grain and also provide a sound and hygient condition to carry cargo ■ All the residual gas must be, thoroughly ■ All the bilge well should be clean and free from any last cargo residual, bilge water and moisture ■ If there is any sign of insect infestation or small vermin, rats or mice, these must be attended to either by spraying with appropriate insecticide or by sealing the holds and fumigating with some approved type fo smoke bomb. Such operation should normally carry out by approved professional in a safe manner. ■ During the cleaning process, close attention should be paid to tank top, ceiling box, beams, frames, spar ceiling, hatch beam, etc. ■ Double burlap warping should be applied on the bilge cover plate and adhered with masking tape ■ Hatch cover should be fully weather-tight and avoid any chance of moisture migration. ■ Rice may also contaminated by odour which can be deodorized by introducing ozone throughout the cargo hold by oxidizing the offending molecules ■ Cargo hooks should not be used for bagged cargo. Flat webbed slings and canvas and pre-slinging may help to reduce the cargo loss ■ They should be protected against obstruction such as beams, brackets, stringers, etc, because as the cargo settles, pressure on the unsupported or projecting part of the bag may result in tearing and spilling the contents. They will be benefit by being protected by mats, paper, etc. from bare steel work and from likely sources of moisture running down bulkhead, pillar, etc and serve to protect the bags from discoloration by rusty metal ■ Sheeting should be provided where loss of cargo might be expected – particularly for valuable cargo, so that sweeping may be collected ad included in the discharge.
(see also seamanship Technique, Second Edition, Vol.1, P.154-155; Shipboard Operation, second edition, H I Lavery, P.265-266)
1994, 1996
B9. Describe how a cargo hold should be prepared to load a cargo of rice in bags after completion of discharging a cargo of coal.
Preparation:
■ cargo hold must be properly cleaned and prepared and all compartments, including sides, stringers, pockets, brackets, etc, must be clean, swept, well ventilated and dried. ■ Rust and scale which might contaminate the cargo must be removed, paint and lime wash may be applied as appropriate to avoid the direct contact of scaled ship side with the grain and also provide a sound and hygiene condition to carry cargo ■ All the residual gas must be, thoroughly ■ All the bilge well should be clean and free from any last cargo residual, bilge water and moisture ■ If there is any sign of insect infestation or small vermin, rats or mice, these must be attended to either by spraying with appropriate insecticide or by sealing the holds and fumigating with some approved type fo smoke bomb. Such operation should normally carry out by approved professional in a safe manner. ■ During the cleaning process, close attention should be paid to tank top, ceiling box, beams, frames, spar ceiling, hatch beam, etc. ■ Double burlap warping should be applied on the bilge cover plate and adhered with masking tape ■ Hatch cover should be fully weather-tight and avoid any chance of moisture migration. ■ Rice may also contaminated by odour which can be deodorized by introducing ozone throughout the cargo hold by oxidizing the offending molecules ■ Cargo hooks should not be used for bagged cargo. Flat webbed slings and canvas and pre-slinging may help to reduce the cargo loss ■ They should be protected against obstruction such as beams, brackets, stringers, etc, because as the cargo settles, pressure on the unsupported or projecting part of the bag may result in tearing and spilling the contents. They will be benefit by being protected by mats, paper, etc. from bare steel work and from likely sources of moisture running down bulkhead, pillar, etc and serve to protect the bags from discoloration by rusty metal ■ Sheeting should be provided where loss of cargo might be expected – particularly for valuable cargo, so that sweeping may be collected ad included in the discharge.
(see also seamanship Technique, Second Edition, Vol.1, P.154-155; Shipboard Operation, second edition, H I Lavery, P.265-266)
1992
9. While loading containers on deck on a ship not specially fitted for containers: i) describe the lifting gear you would use ii) state how the containers should be positioned and secured.
Lifting gear: • Crane and derricks – these require an overhead connection to the container usually supplied by a “spreader”. This is necessary to supply vertical lift at each corner casting to prevent damage to container ■ Twist lock enter the appropriate aperture in the corner casting and when turned 90deg, they engaged ■ A frame may be used with 4 hooks hanging vertical which are manually inserted into the corner castings, in which case the hooks should be pointing outward from the ends of the container to gain maximum support from the seat of the hook and make for ease unhooking when the container is in position. 20 feet and above should never be lifted by direct wire slings from top corner castings without some spreader device to prevent the wire pinching and therefore damaging the container. • Fork lift truck – these must be of sufficient capacity to handle the container if it is loaded. Mast height must be suited to operating with overhead obstruction in the case of Ro-Ro vessel. Smaller capacity folk lift trucks may be used for empty container. If the container has fork lift pockets then the fork truck may be used for direct lifting. Stowage of containers on deck of ships which are not specially designed and fitted for the purpose of carrying containers i. Should be stowed in the fore-and-aft direction ii. Should not extend over the ship’s sides. Adequate support should be provided when containers overhang hatches or deck structures iii. Should be stowed and secured so as to permit safe access for personnel iv. Should at no time overstress the deck or hatches on which they are stowed v. Bottom-tier containers should be stowed on timber of sufficient thickness to transfer the stack load evenly on to the structure of area vi. Use locking devices or cones between containers when stacking vii. Take into consideration of position and strength of securing points Securing of container on non-container ships vi. Secure to protect them from sliding and tipping. Hatch covers carrying containers should be secured to the ship vii. Lashing consist of wire ropes or chains with enough strength and elongation ability viii. Timber shoring should not exceed 2 m in length ix. Wire clips should be adequately greased and tightened x. Lashing should be kept under equal tension xi. Use twist lock for second and upper tier containers
1993, 1995
3. (a) Explain how “ship’s sweat” and “cargo sweat” are formed. (b) State the precautions that should be taken to avoid damage to cargo due to sweat.
Cargo sweat – For ships that have loaded cargo in a relatively cold climate the most likely form of sweat is cargo sweat. If warm, moist air is allowed to enter the hold its temperature may be reduced below its dew point when it comes into contact with cooler cargo. The hull is more likely to have been heated by its direct contact with the warmer water outside. If the temperature of the cargo is below the dew point of the outside air then ventilators should be closed to prevent cargo sweat unless there are other more pressing needs for ventilation.
Ship sweat is, however, more likely to occur when cargo with a high moisture content is loaded in a warm climate. As the ship’s hull is cooled by its contact with the outside water (particularly if proceeding into a cooler area) then the air in the hold adjacent to the ship’s steel will be cooled below its dew point and condensation will take place. Since the cargo will remain warmer than the hull it will continue to both warm the air and feed it further moisture through evaporation. This situation indicates that the air in the hold should be replaced by cooler outside air as quickly as possible.
8. Describe the different materials and methods that may be used for the separation of cargoes.
• Thin netting with different colour • Ropes • Paint • Marking pen (for carton and cased good) • Chalk • Layers of dunnage • Construction of bulkhead from timber/ steel plate • Separation cloth (burlap) • Plastic sheet (ensure restricted vent would not result to spoiling cargo) • Natural separation (cargo of different from, shape or packing)
1994
A3. Describe how inerted tanks are cleaned and gas-freed in a VLCC prior to drydocking.
• When it is desired to gas free a tank after washing the concentration of hydrocarbon vapour should be reduced by purging the inerted cargo tank with I.G • Purge pipes/ vents should be opened to atmosphere and inert gas introduced into tank until hydrocarbon vapour concentration reduced to 2% • Gas freeing may be effected by pneumatically, hydraulically or steam-driven portable blower or by fixed equipment, such tank should be isolated to avoid IG to be entered from IG main. • Gas free should continue until the entire tank has an O2 content of 21% by volume and a reading of less than 1% of lower flammable limit is obtained on a combustible gas indicator • Care must be taken to prevent the leakage of air into inerted tank or of inert gas into tank which are being gas-freed. • The tanks will be cleaned by fixed/ portable machines connected to long hose that are fed with washing agent from tank cleaning main on deck • The washing agent could be cold/ warm water or crude oil. • The first tank to be washed will be the one required for clean ballast once they are completed, clean ballast will be loaded whilst the dirty ballast loaded at the discharge port will be discharged with monitoring system. • The washing agent will be stored in slop tank
(see also Shipboard Operation, second edition, H I Lavery, P. 196-198)
B8. State the precautions that should be observed when loading a heavy lift using the ship’s “Jumbo” derrick.
Q. B8 (see Seamanship Technique, Second Edition, Vol.1, P. 118-121)
See above notes
A3. (a) Sketch and list out the various part of a general dry container.
(b) Describe the various types of container, their sizes, and their usage.
(c) State the precautions that should be observed on Container Stowage before and after operations in a cellular ship.
Q.A3
(a) (see Ship Construction, Firth Edition, D J Eryes P. 180)
(b) Various types of containers:
1. General purpose containers. Standard measurements are 20’ (or 40’) x 8’ x 8’6”. They are used to carry wide range of general cargo.
2. Bulk containers are similar to 20’ (or 40’) GP containers except that they have three circular hatches in the roof for the loading of bulk material, and a further hatch at the bottom of one of the doors for discharge.
3. Ventilation container are also similar to 20’ GP containers except that they are fitted with a passive ventilation system adjacent to the top and bottom side rails
4. Open-sided containers are another variation of the standard 20’ unit. They have one open side that is fitted with a gate (in four sections) and a roll down curtain that may be secured to the top rail. Their major use is for transporting livestock and some perishable commodities
5. Open-top containers may be 20’ or 40’ units that are used for large heavy, tall or awkward items that cannot be loaded through the doors of GP containers.
6. Half-height containers are of standard length and breadth but only 4’3” tall. Their use avoids wasted space when loading high density cargoes like steel rods and pipe.
7. Flat-rack containers are simply 20’ or 40’ containers with no sides or tops. They can therefore be used for unusually large or awkward loads. One particular use is for loading cargo that conforms with cell guide widths but will not fit within the internal dimensions of an open-top container because of the width of the top side rails.
8. Refrigerated containers are insulated against heat loss, have T-section flooring and battens on the doors to allow free circulation of refrigerated air and have integral refrigerated units that are powered from the ship’s supply. They may be 20’ or 40’ in length.
9. Tank containers are simply stainless steel tanks fitted within a standard 20’ or 40’ framework. They have a filling port at the top centre and a discharge port at the bottom of one end and are used for carriage of a variety of both hazardous and non-hazardous liquids.
(c) Container stowage precautions:
Before Operation: i. Ship stresses in various stage of cargo operation shall be appropriate. ii. Ship shall not be suffered from excessive trim to ensure the cell guides are vertical iii. Anti-heeling system shall be operational to ensure the ship upright. iv. Container shall be stowage in accordance with their POD so as to avoid over-stowage/ re-handling. v. DG shall be properly stowed and segregated as per IMDG Code vi. Refrigerated cargo shall be stowed in position where ship’s power supply available vii. Ballast plan shall be drawn up viii. Cargo loading and discharge sequence plan shall be drawn up.
After Operation i. Check containers are stowed as per plan ii. Check containers are properly secured. Twist stacker in hold / twist locks plus lashing rods on deck iii. Check refrigerated cargo are power supplied iv. Check DG are properly stowed, segregated and labeled.
1996
B6. Describe the ship’s cargo gear and lashing systems to load timber in a log carrier. ■ Loose timber of heavy log would load with the use of chain sling / timber log by ship derrick / cranes or quayside cranes. ■ More recently, packaged timber takes the way and utilizes fork lift trucks. It is a more economical, more transportable by mechanical means promote efficiency of handling and reduction in manpower loading/ discharging. ■ Packaged timber should be stowed on deck, in order to facilitate a compact stow ■ Each tier must be equally firm ■ The stow must not impair visibility from bridge and the forward must not have overhanging should which could be caught by a head sea ■ If the ship is to pass through a winter zone, the height of the cargo above the deck must not exceed one third of the ship’s breadth. ■ The cargo must be secured throughout its length by independent transverse lashing not more than 3m apart for cargo height up to 4m above the weather deck and not more than 1.5m apart for cargo height over 6m. the spacing of lashings for cargo between these tow height is calculated by interpolation ■ The breaking strain of the lashing must be at least 13.6t ■ Upright can be used as addition to these lashing whenever necessary to ensure a compact and secure stow. ■ Lashing must be provided with a method of adjusting their tension on passage ■ A suitable walkway must be provided on top of the stow to ensure safe access, with ladders t deck where appropriate ■ Safety lifelines should be rigged where necessary ■ In addition to independent lashing not more than 3m apart, a “hog” wire is rove between port and starboard upright when the logs reach a height of 3/4 of upright ■ As other logs are stowed on top of this wire, it is tightened and the upright are pulled inboard ■ A dual continuous “wiggle” wire is passed from side to side over the top of the cargo, through snatch blocks held in place by foot wire to the deck edge and tensioned by leading the wire to winch.
(see also Shipboard Operation, second edition, H I Lavery, P.243-246)
B6. (a) State the advantages of crude oil washing over water washing. (b) State which tanks should be crude oil washed prior to completion of cargo discharge.
COW advantages:
1. reduced risk of pollution
2. reduction in time of passage tank cleaning
3. reduction in the cost of tank cleaning (both routine and for dry dock)
4. reduction in de-sludging costs
5. reduction of salt water discharged to the refinery
6. reduced corrosion as less salt water is introduced into the tanks during washing
7. increases the time available for maintenance
8. increased carrying capacity (less slops carried)
9. increased discharge rates on overall stripping time
10. increased in the refinable material discharged.
(see Shipboard Operation, Second Edition, H I Lavery, P.196)
Tanks to be COW is laid down in MARPOL • All cargo tanks that are to contain ballast. For a single hulled tanker this will mean the departure (dirty) and arrival (clean) ballast tanks. For an segregated ballast tank tanker only the cargo tank designated as the heavy weather tank need be washed for ballast purposes. • Additionally approximately 25% of tanks on a rotational basis shall be washed for residual control purposes. No tank need be washed more than once every 4 months.
(see Shipboard Operation, second edition, H I Lavery, P.197)[pic]
