Cargo Work
Draft, Trim and Stability
The Load Line Marks
LR – the symbols of the classification society (Lloyds Register) by the side of the Plimsoll mark
TF – Tropical Fresh (water) F – Fresh Water T – Tropical (Sea Water)
S – Summer (Sea Water) W – Winter (Sea Water)
Criteria of Stability:
Extract from the Load Line Rule (1968)
The area under the curve of Righting Levers shall not be less than:
0.055 metre-radians up to an angle of heel of 30˚
0.09 metre-radians up to an angle of heel of 40˚
0.03 metre-radians between the angles of heel of 30˚ and 40˚
The Righting Lever shall be at least 0.20 metre at an angle of heel equal to or greater than 30˚ The maximum Righting Lever shall occur at an angle of heel not less than 30˚
The Initial Transverse Metacentric Height (GM) shall not be less than 0.15 metre
Ship Stability – working with ‘kg’, TM, Draft, Displacement and Trim including LCB and LCF
The following example shows how a ships stability booklet has pre-determined conditions of loading and the consequent stability criteria.
The said condition is 12; each ‘Departure’ condition has an ‘Arrival’ condition.
In the Departure condition the vessel is assumed to be sailing out with a load of cargo and with full bunkers and stores. The ballast is negligible.
In the Arrival condition the vessel is assumed to have arrived her disport/ way port (may be bunkering for long voyage), here the cargo remains the same only change is in the bunkers and FW.
The Arrival condition is to be worked out prior departure since the arrival condition determines the loading of the cargo. Since no vessel would like to arrive a port in a critical condition – not satisfying the stability criteria.
The weight is multiplied with the ‘kg’ of each compartment to obtain the vertical moments. These are added up (all – cargo, ballast, Bunkers and light ship) and the total of the V-M is divided by the displacement to get the final KG
In the same way the weight is multiplied with the ‘lcg’ of each compartment to obtain the longitudinal moments. These are added up (all – cargo, ballast, Bunkers and light ship) and the total of the L-M is divided by the displacement to get the final LCG.
Noting the Displacement the tables are referred to obtain the LCB, Mean Draft and the Trimming Moment. With these inputs the final drafts and the GM is calculated.
For obtaining the Fluid GM, the FSM of the compartments are read off from the tank data sheets.
The total of the FSM when divided by the displacement gives the FSC that is to be subtracted from the GM to obtain the GM (F).
And the following gives the arrival condition for the same ship – the cargo is the same, only change being the fuel and the ballast.
The following are extract from the hydrostatic table of ship ‘A’.
Given that the morning draft in sea water of ship ‘A’ is Forward: 8.92m and Aft: 9.12m Ship ‘A’ loads cargo throughout the morning shift and her sailing drafts are:
Fwd: 8.99m, Aft: 9.19m
To find the amount of cargo loaded. Note, during the morning the ship received H.O. bunkers – 100MT and consumed 10MT of FW.
Morning Mean Draft: (8.92 + 9.12)/ 2 = 9.02m
Displacement at 9.02m: 20419
Displacement at 9.09m: 20604
Thus the difference in displacement would be: (20604 – 20419) = 185 MT
Bunkers received: 100MT
FW consumed: 10MT
Thus the cargo loaded would be: 185 – 100 = 85 MT (correcting for the bunker) and
85 + 10 = 95MT (correcting for the FW consumed)
For change of trim the earlier example is to be referred.
C
C
C
a
a
a
rr
r
g
g
g
o
o
o
W
W
W
o
o
o
rr
r
k
k
k
Securing Cargo
Need for solid stow and securing of all cargoes
Cargo onboard a ship will tend to shift with the motion of the ship. This necessitates the cargo to be lashed (secured) to the ship structure. However the lashing with ropes/ wire ropes/ iron restraining bars is not very effective because of the fact that the tightened lashings have a tendency to work loose with the motion of the ship.
On shore any nut which is fitted tightly on a bolt works loose with vibrations as such - spring washers are used together with check nuts and split pins to prevent the working loose of such nuts. This is not practical on shipboard lashings - except for turnbuckles and bottle screws with restraint bars. Below deck lashings further are not attended to during sailing and if they work loose it is practically impossible to do a very effective job to re-secure them. Temporary measures are often adopted and these may not be very effective as stated earlier.
Thus the only way to prevent the lashings from working loose is to stow the cargo very close to each other and then to shore the cargo with timber. This would prevent the cargo from acquiring momentum while swaying with the ship and thus prevent to a large extent the working loose of the lashings.
For bagged cargo if the same is not stowed solidly and thus allowing too much of broken stowage, would tend to shift with the motion of the ship, thus shifting the centre of gravity laterally and inducing a list to the ship. This coupled with the heeling of the ship would make the weather deck of a ship too close to the water line and thus endanger the safety of the ship.
Bulk cargo on general cargo carriers are therefore saucered with the same cargo, in order to prevent the cargo from shifting to one side.
Deck cargo due to the high KG is especially vulnerable lateral shifting and the lashings work loose and also to part lashing. Especially since the transverse momentum gained by such cargo during the rolling of a ship is liable to part lashings. Thus all deck cargo has to be definitely shored and then also lashed to deny the cargo from gaining any momentum.
Deck cargo - Lashed
Cargo liable to slide during rolling, such as steel rails, should be Stowed fore and aft
All long cargoes such as steel rails, pipes, long steel plates as well as steel coils are stowed with their ends in the fore and aft direction. This again is necessary due to the fact that most of theses cargo cannot be individually lashed they rather grouped into bundles and the bundles are lashed to make many small bundles of pipes or rails as the case may be. This prevents the individual pipes from sliding and since as mentioned the transverse momentum is quite large when the ship is rolling, and the pipes are thus prevented from damaging the sidewalls of the hold. This is severe since repeated banging has resulted in tearing holes in the shipside plates below the waterline and the ship capsizing due the inflow of water.
If the pipes / rails are stowed in the fore and aft direction this is prevented.
This is the first tier. It is important to place the dunnage to spread the load as well as to
facilitate the passing of slings at the disport. The lashing wires are also placed prior to loading the cargo. The size of the bundles should be to the capacity of the derrick/ crane that would be used to discharge the cargo. The number of lashing wires is dependent on the weight of the bundles as well as the length of the cargo.
As each bundle is completed the lashings are closed and tightened. And subsequently dunnage is again placed and the lashing wires again spread on top of the earlier cargo.
Stowage and securing for vehicles and trailers
Vehicle lashing on deck
Force parallel to and across the deck = 1.0 W
Force normal to the deck = 1.4 W
Force in the longitudinal direction = 0.3 W
The above forces are intended to represent the total force to be applied in each direction i.e., the aggregate of the static and the dynamic forces.
Case 1 – Vehicle stowed in Fore and Aft direction:
The forces preventing tipping of the vehicle are the vertical downward force and the lashings holding the vehicle (FLT)
Taking moments about A (the outer edge of wheel i.e., fulcrum position)
FLT x L = (1.0 W x 2/3 H) – (1.4 W – X)
FLT x (X + Y) sin = W (0.67 H – 1.4 X) FLT = (W (0.67 H – 1.4 X) / ((X + Y) sin)
Note the importance of the fulcrum position (A),
The height of the centre of gravity, normally taken as 2/3 H
is the angle of inclination of the lashings
To examine the force causing the vehicle to slide sideways:
For this example a trailer is supported by wheels on the one end and with a trestle at the other end.
In both cases sliding is resisted by the frictional resistance ‘’ between the tyre/ deck and the trestle/ trailer frame and also lashings (FLS).
Case 1 – Effect at the trestle end of trailer.
Note: Assuming ½ total forces act at each end of trailer then effective sliding force = 0.5 W – 0.7 W x Ls (assume 0.2)
= 0.5 W – 0.14 W
Case 2 – Effect at wheel end of trailer.
Effective sliding force = 0.5 W – 0.7 W x (assume 0.4) = 0.5 W – 0.28 W
= 0.22 W
then the force in the lashing resisting sliding = FLS = 0.22 W / cos
Note the importance of ‘’ the coefficient of friction and the angle of inclination of the lashings. In the above it can be seen near vertical lashing is great to prevent tipping but is useless for sliding whereas a near horizontal is great for sliding but is useless for tipping. So a correct angle of inclination should be fixed appropriate for the cargo.
In general the safe working load (S.W.L.) of lashing wires is taken as 1/3 the Breaking load.
If chain is used for lashing then:
If made of H.T. steel then the SWL would be 40% of the Breaking load.
And if made of ordinary steel then the SWL would be 33% of the Breaking load.
Efficient securing of cargoes is essential for the safety of the ship as well as the cargo
Securing of cargo is of prime importance not only for the cargoes themselves but also for the ship as a whole including the crew that sail on her.
Improperly secured cargo will shift in a seaway and can endanger the cargo as well as the ship.
In the worst cases the cargo may fall overboard and may endanger other ships such cargoes like logs and containers have been noted to have floated and come within the sea-lanes.
When a container falls overboard it must be remembered that it does so in spite of it being secured on the ship as well as the opposition to this being offered by the ship structure. Thus when it does go overboard it does after causing a great amount of structural damage.
There are many instances of cargo improperly secured breaking the lashings and punching a hole at or below the waterline and the ship having been lost with casualties.
Deck cargos if they part their lashings are liable to cause extensive damage, which can endanger the watertight integrity. Even minor movement of heavy cargoes has been known to shear off air pipes and sounding pipes resulting in water entering the tanks or other spaces below deck. Fire lines have also been damaged due to inadvertent movement of cargo.
Accommodation ladders as well as companionway can be damaged due to the cargo movement on deck in a seaway.
Even if the ship is not lost the damage such heavy cargoes can bring upon the structure of the ship is very heavy. Crew has often been sent to re-secure such cargo in rough weather with the crew suffering loss of limbs and other injuries.
Stowage and securing of deck cargo should be adequate for the worst conditions which could be experienced
Good stowage and good securing arrangement should be foreseen prior loading the cargo. If it is required extra lugs and eyes on deck have to be welded to provide lashing points for the cargo- this is generally done for heavy lifts or cargoes of odd sizes.
Securing should be always for the worst weather that would be encountered. Many a ship have suffered damage to cargoes and to their own structure by neglecting good and adequate lashing while on a short voyage, failing to take into account diversions and anchorage at open roadstead and cyclonic weather.
Hatches should be securely closed and cleated before loading over them
Once the cargo below deck has been loaded and all securing has been completed (securing can continue after the hatches are secured provided there is adequate space for the crew to enter and to lash), the hatches are closed and battened down and all cleats and centre wedges should be in place.
Only after the above have been completed should any cargo be loaded on to the hatch tops.
If this is not done, and the hatch is battened down after the cargo has been loaded on to the hatch tops the battening down and the fitting of the cleats as well as the centre wedges
would be ineffective since the weight of the cargo would not permit the hatch covers to be correctly in place and the hatch would leak in a seaway or even in rain.
Deck Cargo
Cargo which are normally carried on deck include the following but are not limited to these and many exceptional cargoes may be carried and also have been carried in the past.
Dangerous cargo – IMDG cargo not permitted on deck
Large packages which due to any size restriction may have to be loaded on to the deck
The above includes engineering or construction equipment
Odd size package
Where the bulk volume far exceeds the weight of the cargo – knocked down bridges, port equipment – not easily liable to weather damage.
Occasionally livestock in limited numbers
Onions or other perishables – short voyages with the weather holding
Yachts – luxury boats.
Cast iron goods – man hole covers – pipes.
The list is endless and it all depends on the routes, the trading pattern and the weather.
The cargo whether on deck or under deck stow has to be stowed well and the cargo should be prevented from moving and gaining enough momentum to part lashings and damage the ship structure.
Deck cargo is liable to damage itself – fall overboard and thus be lost. However the misery does not stop here in the act of parting lashing and going overboard the deck cargo unleashes considerable damage to the ship structure as well as the crewmembers.
Small apparently insignificant items such as sounding pipes and air pipes are often torn out and this may endanger the ship from the resulting chances of flooding lower down
Crewmembers ordered to lash cargo where the lashings have parted have been seriously injured and some have lost lives combating the shifting cargo.
The point is to have a good solid stow – prevent the cargo from shifting and gaining
momentum with the shift. Since this would part any strong lashing. The lashing undertaken should be for the worst sea condition that may be experienced.
Deck cargo loading on top of hatch covers should be carefully planned. All loading of under deck spaces should have been completed – lashing may continue with portable lights.
The hatch covers should be closed and battened down – all side wedges as well as cross wedges (centre wedges) should have been fitted. With the hatch cover sealed for sea, the space should then be given out for loading of deck cargo.
The permissible load density of the hatch covers should be checked and timbers laid to spread the weight of the cargo. The load density of the hatch covers are given for a new vessel and as the ship ages the load density would reduce due to fatigue of the metal as well as wear and tear. Thus the utmost need to spread the weight using timber.
Shoring and toming of the hatch cover from below deck is practically useless since the hatch cover moves/ slides somewhat with the motion of the ship.
The height of the cargo on the hatch covers as well as that on deck should not be so high that the view is obstructed from the Navigating Bridge.
The above photographs show the extent of the weight that Ice accumulation can pose for a ship. The weight on deck may eventually lead a ship to progress to a condition of ‘angle of loll’.
The weight of the ice may be in excess of a hundred tonnes, and thus the danger of a ship regarding stability.
As with the above any deck cargo for that matter would have a very high KG as such the GM (F) would be quite small. Especially in the case of GC vessels, which do not have a very large GM (F) the loading of deck cargo, is bound to lead to further loss of GM (F). If the ship loads the deck cargo with her own gear then the ship would during the loading operation have still further low GM (F) due to the KG of the load being at the top of the derrick/ crane for part of the loading sequence.
Containers on deck
Containers when they are loaded on deck are subject to the following consideration – barring stability, which would have been planned for.
The load density of the deck
Spreading the load of the container evenly
Chocking the container base to prevent shifting due to rolling or pitching
Placing the containers in as close a group as possible
Safeguarding the sounding pipes and the air pipes within the periphery of the container space.
Keeping the fire hose boxes clear as well as the passage leading to them, the fire hydrants should similarly be kept clear.
No lashing should be taken which would damage or cause to be damaged the fire lines.
Checking that the leads for the lashing wires are adequate as well as that the chocking points are well supported
Keeping a passage for crew members to check the lashings during g voyage.
In general the close stow is difficult on GC vessels where the container is usually loaded between the hatch coaming and the bulwark. So the container should be loaded as close as possible to the hatch coaming, as well as close to the Mast House structure. If few
containers are being loaded then the shelter offered by the Mast House structure should be kept in mind.
The load is spread by having the container loaded onto timbers at least 4” x 4”. The timbers should be extended to well beyond the shoe of the container in all directions to spread the load. Once this is done the chocking of the container is started. Again heavy timbers are used and the container is first secured to prevent any lateral and transverse shifting. While
selecting chocking points all heavy framework should be selected. Bulwark stays are not strengthened enough to be used as chocking points. Hatch coamings may be used and as a last resort bulwark stays. After the chocking is completed the container is lashed. The lashing is further to prevent the longitudinal as well as the transverse shifting. For this the base shoes offer the best lashing points. To prevent the container being bodily shifted out the lashings are continued to the top shoes.
All lashing should be separate in the sense that a single lashing wire should not be passed over a few shoes and then lashed at the final point. Each lashing should have a turnbuckle or bottle screw incorporated and there should be at least 60% free thread in them after
The bottom lashing and the top lashing should not be counted together fore the purpose of assessing the total number of lashings taken for the container.
The top lashings are for bodily rise and as such should be counted separately.
As a thumb rule, if the SWL of the lashing wire is 2T then to lash the top of a 20T container the number of lashings should be a minimum of 10 (all well positioned), similarly the bottom should have 10. The bottom lashings may be reduced depending upon the chocking of the container and the availability of the lashing point.
Note that a single strong point for lashing should not have more than 2 lashing wires – the preferred would be 1, however it is often impossible to find so many lashing points.
This shows a container ship lashing; note that the container is loaded onto the ship shoe slots which are strengthened, the rod lashings are only for the top of the containers.
Here the bottom shoes are not lashed since the ships sunken shoes and twist locks effectively chock and lash the bottom of the container.
Stowage and Lashing of Timber deck cargoes as laid down by IMO code of Safe Practice for Ships Carrying Timber Deck Cargoes
Purpose
The purpose of the Code is to make recommendations on stowage, securing and other operational safety measures designed to ensure the safe transport of mainly timber deck cargoes.
Application
This Code applies to all ships of 24 m or more in length engaged in the carriage of timber deck cargoes. Ships that are provided with and making use of their timber load line should also comply with the requirements of the applicable regulations of the Load Line
Convention.
Timber means sawn wood or lumber, cants, logs, poles, pulpwood and all other type of timber in loose or packaged forms. The term does not include wood pulp or similar cargo.
Timber deck cargo means a cargo of timber carried on an uncovered part of a freeboard or superstructure deck. The term does not include wood pulp or similar cargo.
Timber load line means a special load line assigned to ships complying with certain
conditions related to their construction set out in the International Convention on Load Lines and used when the cargo complies with the stowage and securing conditions of this Code.
Weather deck means the uppermost complete deck exposed to weather and sea.
The stability of the ship at all times, including during the process of loading and unloading
timber deck cargo, should be positive and to a standard acceptable to the Administration. It should be calculated having regard to:
The increased weight of the timber deck cargo due to:
Absorption of water in dried or seasoned timber, and
Ice accretion, if applicable;
Variations in consumables;
The free surface effect of liquid in tanks; and
Safety precautions to be taken as far as stability of the ship is concerned
The master should:
Cease all loading operations if a list develops for which there is no satisfactory explanation and it would be imprudent to continue loading;
Before proceeding to sea, ensure that:
The ship is upright;
The ship has an adequate metacentric height; and
The ship meets the required stability criteria.
Ships carrying timber deck cargoes should operate, as far as possible, with a safe margin of stability and with a metacentric height which is consistent with safety requirements but such metacentric height should not be allowed to fall below the recommended minimum.
However, excessive initial stability should be avoided as it will result in rapid and violent motion in heavy seas which will impose large sliding and racking forces on the cargo causing high stresses on the lashings. Operational experience indicates that metacentric height should preferably not exceed 3% of the breadth in order to prevent excessive accelerations in rolling provided that the relevant stability criteria are satisfied.
This recommendation may not apply to all ships and the master should take into consideration the stability information obtained from the ship’s stability manual.
STOWAGE
General
Before timber deck cargo is loaded on any area of the weather deck:
Hatch covers and other openings to spaces below that area should be securely closed and battened down;
Air pipes and ventilators should be efficiently protected and check valves or similar devices should be examined to ascertain their effectiveness against the entry of water;
Accumulations of ice and snow on such area should be removed; and
It is normally preferable to have all deck lashings, uprights, etc., in position before loading on that specific area. This will be necessary should a preloading examination of securing
equipment be required in the loading port.
The timber deck cargo should be so stowed that:
Safe and satisfactory access to the crew’s quarters, pilot boarding access, machinery spaces and all other areas regularly used in the necessary working of the ship is provided at all times;
Where relevant, openings that give access to the areas can be properly closed and secured against the entry of water;
Safety equipment, devices for remote operation of valves and sounding pipes are left accessible; and
It is compact and will not interfere in any way with the navigation and necessary working of the ship.
During loading, the timber deck cargo should be kept free of any accumulations of ice and snow.
Upon completion of loading, and before sailing, a thorough inspection of the ship should be carried out. Soundings should also be taken to verify that no structural damage has occurred causing an ingress of water.
On ships provided with, and making use of, their timber load line, the timber deck cargo should be stowed so as to extend:
.1 over the entire available length of the well or wells between superstructures and as close as practicable to end bulkheads;
.2 at least to the after end of the aftermost hatchway in the case where there is no limiting superstructure at the aft end;
.3 athwartships as close as possible to the ship sides, after making due allowance for
obstructions such as guard rails, bulwark stays, uprights, pilot boarding access, etc., provided any area of broken stowage thus created at the side of the ship does not exceed a mean of 4% of the breadth; and
.4 to at least the standard height of a superstructure other than a raised quarterdeck.
The basic principle for the safe carriage of any timber deck cargo is a solid stowage during all stages of the deck loading. This can only be achieved by constant supervision by shipboard personnel during the loading process.
SECURING
General
Every lashing should pass over the timber deck cargo and be shackled to eye plates and adequate for the intended purpose and efficiently attached to the deck stringer plate or other strengthened points. They should be installed in such a manner as to be, as far as practicable, in contact with the timber deck cargo throughout its full height.
All lashings and components used for securing should:
.1 possess a breaking strength of not less than 133 kN;
.2 after initial stressing, show an elongation of not more than 5% at 80% of their breaking strength; and
.3 show no permanent deformation after having been subjected to a proof load of not less than 40% of their original breaking strength.
Every lashing should be provided with a tightening device or system so placed that it can safely and efficiently operate when required. The load to be produced by the tightening device or system should not be less than:
.2 16 kN in the vertical part.
NOTE: 1 Newton equals 0.225 lbs. force or 0.1 kgf.
Upon completion and after the initial securing, the tightening device or system should be left with not less than half the threaded length of screw or of tightening capacity available for future use.
Every lashing should be provided with a device or an installation to permit the length of the lashing to be adjusted.
The spacing of the lashings should be such that the two lashings at each end of each length of continuous deck stow are positioned as close as practicable to the extreme end of the timber deck cargo.
If wire rope clips are used to make a joint in a wire lashing, the following conditions should be observed to avoid a significant reduction in strength:
.1 the number and size of rope clips utilized should be in proportion to the diameter of the wire rope and should not be less than four, each spaced at intervals of not less than 15 cm;
.2 the saddle portion of the clip should be applied to the live load segment and the U-bolt to the dead or shortened end segment;
.3 rope clips should be initially tightened so that they visibly penetrate into the wire rope and subsequently be retightened after the lashing has been stressed.
Greasing the threads of grips, clips, shackles and turnbuckles increases their holding capacity and prevents corrosion.
Uprights
Uprights should be fitted when required by the nature, height or character of the timber deck cargo.
When uprights are fitted, they should:
.1 be made of steel or other suitable material of adequate strength, taking into account the breadth of the deck cargo;
.2 be spaced at intervals not exceeding 3 m;
.3 be fixed to the deck by angles, metal sockets or equally sufficient means; and
.4 if deemed necessary, be further secured by a metal bracket to a strengthened point, i.e., bulwark, hatch coaming.
Loose or packaged sawn timber
The timber deck cargo should be secured throughout its length by independent lashings.
The maximum spacing of the lashings should be determined by the maximum height of the timber deck cargo in the vicinity of the lashings:
.1 for a height of 4 m and below, the spacing should be 3 m;
.2 for heights of above 4 m, the spacing should be 1.5 m.
The packages stowed at the upper outboard edge of the stow should be secured by at least two lashings each.
When the outboard stow of the timber deck cargo is in lengths of less than 3.6 m, the spacing of the lashings should be reduced as necessary or other suitable provisions made to suit the length of timber.
Rounded angle pieces of suitable material and design should be used along the upper outboard edge of the stow to bear the stress and permit free reeving of the lashings.
Logs, poles, cants or similar cargo
The timber deck cargo should be secured throughout its length by independent lashings spaced not more than 3 m apart.
If the timber deck cargo is stowed over the hatches and higher, it should, in addition be further secured by:
.1 a system of athwarthship lashings (hog lashings) joining each port and starboard pair of uprights near the top of the stow and at other appropriate levels as appropriate for the height of the stow; and
.2 a lashing system to tighten the stow whereby a dual continuous wire rope (wiggle wire) is passed from side to side over the cargo and held continuously through a series of snatch blocks or other suitable device, held in place by foot wires.
The dual continuous wire rope should be led to a winch or other tensioning device to facilitate further tightening.
Testing, examination and certification
All lashings and components used for the securing of the timber deck cargo should be tested, marked and certified according to national regulations or an appropriate standard of an internationally recognized standards institute. Copies of the appropriate certificate should be kept on board.
No treatments, which could hide defects or reduce mechanical properties or strength, should be applied after testing.
A visual examination of lashings and components should be made at intervals not exceeding 12 months.
A visual examination of all securing points on the ship, including those on the uprights, if fitted, should be performed before loading the timber deck cargo. Any damage should be satisfactorily repaired.
Lashing plans
One or more lashing plans complying with the recommendations of this Code should be provided and maintained on board a ship carrying timber deck cargo.
Personnel Protection And Safety Devices
During the course of the voyage, if there is no convenient passage for the crew on or below the deck of the ship giving safe means of access from the accommodation to all parts used in the necessary working of the ship, guard lines or rails, not more than 330 mm apart
vertically, should be provided on each side of the deck cargo to a height of at least 1 m above the cargo. In addition, a lifeline, preferably wire rope, set up taut with a tightening device should be provided as near as practicable to the centreline of the ship. The stanchion supports to all guard rails or lifelines should be spaced so as to prevent undue sagging. Where the cargo is uneven, a safe walking surface of not less than 600 mm in width should be fitted over the cargo and effectively secured beneath, or adjacent to, the lifeline.
Where uprights are not fitted, a walkway of substantial construction should be provided having an even walking surface and consisting of two fore and aft sets of guard lines or rails about 1 m apart, each having a minimum of three courses of guard lines or rails to a height of not less than 1 m above the walking surface. Such guard lines or rails should be supported by rigid stanchions spaced not more than 3 m apart and lines should be set up taut by tightening device.
As an alternative a lifeline, preferably wire rope may be erected above the timber deck cargo such that a crewmember equipped with a fall protection system can hook onto and work about the timber deck cargo. The lifeline should be:
.1 erected about 2 m above the timber deck cargo as near as practicable to the centreline of the ship;
.2 stretched sufficiently taut with a tightening device to support a fallen crewmember without collapse or failure.
Properly constructed ladders, steps or ramps fitted with guard lines or handrails should be provided from the top of the cargo to the deck, and in other cases where the cargo is stepped, in order to provide reasonable access.
Action To Be Taken During The Voyage
Tightening of lashings
It is of paramount importance that all lashings be carefully examined and tightened at the beginning of the voyage as the vibration and working of the ship will cause the cargo to settle and compact. They should be further examined at regular intervals during the voyage and tightened as necessary.
Entries of all examinations and adjustments to lashings should be made in the ship’s logbook.
Container Cargo
Sea Containers were invented in the mid 1950s by Malcolm McLean, a North Carolina trucking owner who grew tired of wasting his trucking company’s time with trucks standing idle in line as ships were unloaded bit by bit by dockworkers.
McLean developed sealed truck trailers and the concept of loading and unloading the trailer interiors only at the points of origin and destination.
The first ship modified to accept these “containers” on deck, sailed with 58 of them from New York to Houston in April 1956. This was the start of McLean’s company, the Sea-Land Corporation.
The Matson Line (Hawaii) put the first fully containerized ship into service in 1960.
The International Standards Organization (ISO) first established container standards in 1961. The ISO standard is not prescriptive and instead simply stipulates tests that the containers must pass.
Modern container ships have only one problem – when the ship arrives in port, the object is to unload the containers quickly to get them on to their final destination and to get the container ships back out to sea fully loaded heading for the next port.
To accomplish this, container ships are equipped with steel skeletons called “cell guides”.
A special lifting fixture is used with remote actuators, which engage the corner blocks on the top of the container.
A recent survey indicates that port crane operators can execute full crane cycles to remove and position containers at rates of between 30 and 60 boxes per hour.
Containers come in two basic sizes – 20 Footer and 40 Footer and are commonly known as TEU (Twenty Equivalent Units) and FEU (Forty Equivalent Units).
The external body of the container is made of corrugated sheet metal and is not capable of taking any load. The four corners have shoes and are strengthened to take in load.
The inside bottom has a wooden ceiling. There are weather-insulted vents provided to facilitate venting.
The weights marked on the containers are TARE weight and LADEN weight. TARE weight is the weight of the empty container and is usually 2200KGS for a TEU, while the LADEN weight may be anything from 20000KGS to 32000KGS (strengthened steel construction).
The container shoes fitted at the corners are hollow with 5 oval slots to facilitate the fitting of container fittings as well as for lifting the container – either by using conventional wire slings or by spreaders.
Since the containers are concentrated weights the loading of the same require special heavy dunnaging to spread the load evenly over the deck – if carried as deck cargo on conventional general cargo ships.
However the carriage of containers are primarily on container ships or on ships, which have been built to take in general cargo as well as containers to a limited extent.
Lashing of containers on purpose ships are supplied from reputed lashing makers and have been tested for the loads they are to lash. Various fittings are used and all of these are generally carried on board.
Corner Eye Pad Side Stack Thrust Bridge Fitting
Twist Lock Rod Lashing Bar Spacer Stacker
A spacer stacker is used where there is a difference between adjacent containers as loaded in their heights, one being the 8ft and the other 8.5FT.
On normal ships where these fittings may not be available wire ropes are used however the number of ropes to be used would be decided by the weight of the container.
On GC ships with no provision for built in shoes only single height loads are carried.
However on container ships the hold stacks may extend to 7 high and on hatch top/ deck to 5 high.
The hold and the deck/ hatch top being strengthened.
The lashings to be done are specified in the container-lashing manual supplied to the ship from the building yard. This is not to be reduced since the stresses have been calculated and the number of lashings incorporated.
The containers are loaded onto a container ship in a specified manner. The ship is divided into BAYS or ROWS. Looking from the side the bays are marked from forward to aft.
The containers are stacked in tiers and are in general called the stacks.
This way ensures that any container can be located very easily – knowing the bay number and the row number isolates the location and the stack height give the exact position of the
container.
On container ships the containers are lowered onto slots inside the holds, the holds bottom is provided with sunken shoes, twist locks/ stackers are fitted onto these and the container is lowered onto them.
Some containers are designed to carry refrigerated cargo, these special containers have their own cooling plant in built on one end of the container, and all that is required for the ship to provide is a power point for the electricity. The containers come with their own recording device and card, the ships officers has to renew the card on the expiry of the same, and is to see that the cooling plant does not stop functioning, manuals are provided whereby ships staff can do some minor repairs to the plant.
Today a variety of cargo which previously was thought could only be loaded onto a general cargo ship, is transported on container ships. An example is a tank, thus small parcels of liquid is carried on container ships.
Lashing of containers is very important since a typical container ship has a low GM(F), consequently the ship rolls quite a bit and the stresses developed by the cargo swaying is liable to break the lashings and put the containers into the sea.
All lashings are to be done following the ships lashing manual. In general the following is a typical lashing system, others may also be accepted if permitted by the manual.
The planning of loading of a container ship is normally undertaken ashore, but the officer in charge of the watch should keep an eye on the loading to detect errors in stowage which may occur. A particular watch should be kept for containers with dangerous goods placards to see that their stowage satisfies segregation requirements as laid down in the IMDG code.
Other things to watch for are that container marked for underdeck stowage do not end up on deck – this is serious since the container may be for second port by rotation, also the heavier containers are generally loaded underdeck to increase the GM. Thus in addition to a loss of GM the ship would also have a mess up at the disport.
Refrigerated containers should be loaded where they can be connected to the ship’s power supply and the duty officer is to ensure the same. While loading a slight slackening of watch can become a liability since the gantries load very fast and to unload or to shift is expensive and time consuming – even if the fault actually is of the port.
Sometimes containers are loaded which due to the nature of the contents have to be
overstowed, in this case the container is loaded and the container is then blocked off so that there would be no chance of any pilferage – such containers may carry – currency/ coins, drugs, and mail or other high value cargo.
Bulk Cargo (Not Grain)
Bulk cargoes (other than grain)
The officer of the watch should know the pre-planned loading procedure regarding quantities to be loaded in each space, the order of deballasting tanks and shifting the vessel under loading chutes. The procedure will have been worked out to keep stresses within acceptable limits and to finish with a satisfactory weight distribution and trim. The officer of the watch should see that the plan is followed, particularly at berths with only one loading chute, to avoid over-stressing the ship.
Code of Safe Practice for Solid Bulk Cargoes BC Code is intended to set a standard for the safe stowage and carriage of solid bulk cargoes.
This Code is a recommended guide for ship owners, shippers and masters and shall apply to all shipments of bulk cargoes.
The list of products appearing in the Appendices of the BC Code, however, is by no means exhaustive. Consequently, before any bulk cargo is loaded, it is essential to ascertain (normally from the shipper) the current physical and chemical properties of the cargo, as required under SOLAS Chapter VI.
General requirements
Before and during loading, transport and unloading of bulk cargoes, all necessary safety precautions including any regulations or requirements should be observed, including the following:
1. Dangerous Bulk Material Regulations
2. Safe Working Practices Regulations
3. International Maritime Dangerous Goods Code (IMDG Code)
4. Emergency Procedures For Ships Carrying Dangerous Goods
5. Medical First Aid Guide for Use in Accidents Involving Goods (MFAG)
6. IMO BC Code - Code of Safe Practice for Solid Bulk Cargoes
Poisoning and asphyxiation hazards
Certain bulk cargoes are liable to oxidation, which in t urn may result in oxygen depletion, emission of toxic fumes and self-heating. Other bulk cargoes may not oxidize but may emit toxic fumes.
It is important therefore that the shipper inform the master before loading of the existence of any chemical hazards. The master should refer to Appendix B of the BC Code and take the necessary precautions, especially those pertaining to ventilation.
Certain cargoes may emit toxic gases when wetted. In these cases the ship should be provided with the appropriate gas detection equipment.
A flammable gas detector is only suitable for testing the explosive nature of gas mixtures.
Emergency entry into a cargo space should be undertaken only by trained personnel wearing self-contained breathing apparatus, and protective clothing if considered necessary, always under the supervision of a responsible officer.
In the event of emergency entry into a cargo space, in addition to the above requirement, spare self-contained breathing apparatus, safety belts and safety lines should be readily available.
Health hazard from dust
To minimize the chronic risks from exposure to the dust of certain materials carried in bulk, a high standard of personal hygiene for those exposed to the dust cannot be too strongly emphasized. The precautions should include not only the use of appropriate protective clothing and barrier creams when needed but also adequate personal washing especially before meals, and laundering of outer clothing.
Flammable atmosphere
Dust created by certain cargoes may constitute an explosion hazard, especially, during loading, unloading and cleaning. This risk can be minimized at such times by ensuring that ventilation is sufficient to prevent the formation of a dustladen atmosphere and by hosing down rather than sweeping.
CARGOES THAT MAY LIQUEFY (section 7 of the BC Code) Properties, characteristics and hazards
Cargoes that may liquefy include concentrates, certain coals and other materials having similar physical properties. Appendix A of the BC Code contains a list of such cargoes, which generally consist of a mixture of small particles in contrast with natural ores that include a considerable percentage of large particles or lumps.
Section 5 of the BC Code - Trimming Procedures
At moisture content above that of the transportable moisture limit, shift of cargo may occur as a result of liquefaction.
The major purpose of the sections of this Code dealing with these cargoes is to draw the attention of masters and others to the latent risk of cargo shift, and to describe the precautions deemed necessary to minimize this risk.
Such cargoes may appear to be relatively dry and granular when loaded, but may contain sufficient moisture as to become fluid under the stimulus of compaction and the vibration that occurs during a voyage.
In the resulting viscous fluid state, cargo may flow to one side of the ship when it rolls one way, but not completely return when it rolls the other. Thus, the ship sways progressively until it reaches a dangerous heel and capsizes.
To prevent subsequent shifting, and also to decrease the effects of oxidation of material with a predisposition to oxidize, these cargoes should be trimmed reasonably level on completion of loading, irrespective of the angle of repose.
Amended Extract from SOLAS Chapter VI Part B
Special provisions for bulk cargoes other than grain Regulation 6
Acceptability for shipment
Concentrates or other cargoes which may liquefy shall only be accepted for loading when the actual moisture content of the cargo is less than its transportable moisture limit.
However, such concentrates and other cargoes may be accepted for loading even when their moisture content exceeds the above limit, provided that safety arrangements to the
satisfaction of the Administration are made to ensure adequate stability in the case of cargo shifting and further provided that the ship has adequate structural integrity.
Prior to loading a bulk cargo which is not a cargo classified but which has chemical properties that may create a potential hazard, special precautions for its safe carriage shall be taken.
Regulation 7
Loading, unloading and stowage of bulk cargoes
To enable the master to prevent excessive stresses in the ship’s structure, the ship shall be provided with a booklet, which shall be written in a language with which the ship’s officers responsible for cargo operations are familiar. The booklet shall, as a minimum, include:
.1 stability data,
.2 ballasting and de-ballasting rates and capacities;
.3 maximum allowable load per unit surface area of the tank top plating;
.4 maximum allowable load per hold;
.5 general loading and unloading instructions with regard to the strength of the ship’s structure including any limitations on the most adverse operating conditions during loading, unloading, ballasting operations and the voyage;
.6 any special restrictions such as limitations on the most adverse operating conditions imposed by the Administration or organization recognized by it, if applicable; and
.7 where strength calculations are required, maximum permissible forces and moments on the ship’s hull during loading, unloading and the voyage.
Before a solid bulk cargo is loaded or unloaded, the master and the terminal representative shall agree on a plan* which shall ensure that the permissible forces and moments on the ship are not exceeded during loading or unloading, and shall include the sequence, quantity and rate of loading or unloading, taking into consideration the speed of loading or unloading, the number of pours and the de-ballasting or ballasting capability of the ship. The plan and any subsequent amendments thereto shall be lodged with the appropriate authority of the port State.
Bulk cargoes shall be loaded and trimmed reasonably level, as necessary, to the boundaries of the cargo space so as to minimize the risk of shifting and to ensure that adequate stability will be maintained throughout the voyage.
When bulk cargoes are carried in ‘tween-decks, the hatchways of such ‘tween-decks shall be closed in those cases where the loading information indicates an unacceptable level of stress of the bottom structure if the hatchways are left open. The cargo shall be trimmed
reasonably level and shall either extend from side to side or be secured by additional longitudinal divisions of sufficient strength. The safe load-carrying capacity of the ‘tween-decks shall be observed to ensure that the deck-structure is not overloaded.
The master and terminal representative shall ensure that loading and unloading operations are conducted in accordance with the agreed plan.
If during loading or unloading any of the limits of the ship are exceeded or are likely to become so if the loading or unloading continues, the master has the right to suspend
operation and the obligation to notify accordingly the appropriate authority of the port State with which the plan has been lodged. The master and the terminal representative shall ensure that corrective action is taken. When unloading cargo, the master and terminal representative shall ensure that the unloading method does not damage the ship’s structure.
The master shall ensure that ship’s personnel continuously monitor cargo operations. Where possible, the ship’s draught shall be checked regularly during loading or unloading to confirm the tonnage figures supplied. Each draught and tonnage observation shall be recorded in a
cargo logbook. If significant deviations from the agreed plan are detected, cargo or ballast operations or both shall be adjusted to ensure that the deviations are corrected.
At a moisture content above that of the transportable moisture limit, shift of cargo may occur as a result of liquefaction.
Many cargoes may appear to be relatively dry and granular when loaded, but may contain sufficient moisture as to become fluid under the stimulus of compaction and the vibration that occurs during a voyage.
In the resulting viscous fluid state, cargo may flow to one side of the ship when it rolls one way, but not completely return when it rolls the other. Thus, the ship way progressively reaches a dangerous heel and capsize.
Ships other than specialist suited ones shall carry only those cargoes having a moisture content that is not in excess of the transportable moisture limit as defined in this Code.
Specially suited ships
Specially suited ships may carry concentrates having a moisture content in excess of the transportable moisture limit if the ship possesses a valid document of approval from her administration, accompanied by such stability information as her administration may require. The document of approval must clearly state “For carriage of concentrates having a moisture content in excess of the transportable moisture limit”.
When concentrates are loaded that have a moisture content in excess of the transportable moisture limit, the whole surface area of each cargo space shall be trimmed level.
Cargoes having a moisture content in excess of the flow moisture point shall not be carried in bulk.
Before loading, the shipper or his appointed agents shall provide to the master and the port warden, if requested, details, as appropriate, of the characteristics and properties of any material constituting bulk cargo, such as flow moisture point, stowage factor, moisture content, angle of repose, chemical hazards, etc. so that any necessary safety precautions can be put into effect.
To do this the shipper shall arrange, possibly in consultation with the producers, for the cargo to be properly sampled and tested. Furthermore, the shipper should provide the ship’s
master and the port warden, if requested, with the appropriate certificates of test, as applicable for a given cargo.
Before and during loading, auxiliary check tests of the moisture content may be carried out using instruments designed specifically for that purpose, such as the “SPEEDY MOISTURE TESTER”. Tests conducted with this instrument indicate a precision of ±1% compared with the laboratory method, i.e., with a laboratory reading of 10%, the “SPEEDY” reading could range from, 9% to 11%. If the readings obtained by this method are consistently higher than those shown on the certificate, loading of the cargo should cease and a further laboratory test be conducted.
If the master has doubts as regards the appearance of condition of the cargo for safe shipment, the following auxiliary method may be used on board ship or at the dockside to perform a check test for approximately determining the possibility of flow:
Half fill a cylindrical can or similar container (0.5-1 litre capacity) with a sample of cargo. Take the can in one hand and bring it down sharply from a height of about 0.2m to strike a hard surface such as a solid table. Repeat the procedure twenty-five times at one or two second intervals. Examine the surface for free moisture or fluid conditions. If free moisture or a fluid condition appears, make arrangements to have additional laboratory tests on the cargo conducted before it is accepted for loading.
COAL is very liable to spontaneous heating. If there is sufficient oxygen available,
combustion is liable to take place. The amount of heating that takes place depends on the type of type coal and how much heat can be dispersed by ventilating the coal. Ventilation can be a double-edged weapon as although it takes heat from the coal it also allows unwanted oxygen into the coal. To keep the coal as cool as possible it should be stowed away from hot bulkheads. To keep oxygen away from the coal only surface ventilation should be allowed.
All spar ceiling or cargo battening should be removed as besides the liability of it to damage, it can give unwanted air pockets in the coal. Unwanted air may also get into a cargo through a temporary wooden bulkhead. If such a bulkhead has been constructed all cracks should be sealed, preferably by pasting paper over both sides of the bulkhead.
Freshly mined coal absorbs oxygen, which, with extrinsic moisture, forms peroxides. These in turn breakdown to form carbon monoxide and carbon dioxide.
Heat is produced by this exothermic reaction causing further oxidation and further heat. If this heat is not dissipated ignition will occur. This is called Spontaneous combustion.
As this is essentially a surface reaction the smaller the surface available for the absorption of oxygen the better. Every attempt should be made to prevent undue breakage of the coal whilst it is being loaded. It may be noted that 1 MT of coal in an unbroken cube has a surface area of about 3.72m2, whereas if it is broken up to pass through a 1.5mm mesh screen its surface area is nearly 4000m2. If a large amount of breakage occurs the small coal with the large surface area is found in the centre of the hold, whilst the large coal will roll down the sides. This aggravates the situation, as the large coal gives a good path for air to flow to the smaller coal where the spontaneous heating is most liable to occur.
Most coal fires in cargo occur at about ‘tween deck level and this is the area where the greatest attention should be paid to temperature and the restriction of through ventilation.
The following are recommendations for the carriage of coal.
The ventilators to the lower holds should be so arranged that they might be opened or closed at will during the voyage.
As the critical temperature at which the process of spontaneous heating in coal becomes greatly accelerated is in some varieties of coal as low as 36˚C, and generally is not much higher, the need of keeping the exteriors surface of the hull, and thereby the interior of the ‘tween decks and holds, as cool as possible is manifest.
The iron decks of ships carrying coal in the tropics can be covered with dunnage to lessen heating.
Suitable means should be provided for ascertaining from time to time the temperature of the lower mass of coal, particularly below the hatchways, and this might be done by means of two pipes leading down to the bottom of the coal at each hatchway.
The temperature tubes should have closed ends to prevent admission of air into the cargo. The temperature of the coal at three heights should be taken daily.
Gas from the holds or ‘tween decks space may find its way into shaft, peaks, chain lockers or similar space unless the bulkheads and casings are maintained in gas tight conditions.
Naked lights should not be used in holds or other spaces in which gas may accumulate until the spaces have been well ventilated.
Full use should, when necessary, be made of the breathing apparatus or smoke helmet and the safety lamp, which form part of the ship’s statutory fire appliances.
The employment of the crew in chipping and painting below decks during the voyage should be avoided. The danger from smoking should be realized and no oily waste, wood, old rope, sacking etc. should be left below where it can become ignited by spontaneous heating
On arrival at the port of discharge the hold ventilators should be unplugged and the lower hold well ventilated before commencing to work cargo.
Coal is frequently loaded from a single tip and earlier it was necessary to drift the vessel fore and aft so that all holds may be filled. To keep these shifts to a minimum No.2 was first put under the tip.
After about one third the capacity of the hold was loaded the vessel was shifted so that No. 3 was loaded to about one third of its capacity. Likewise the remaining after holds were loaded and then the tip was shifted astern to reach No. 1, half the capacity was put in, before shifting to No. 2, which was then filled.
The other after holds were now filled in order excepting the aftermost. The aftermost hold and the No.1 were now worked so that the vessel would complete loading in a good trim.
Coal is sometimes graded, when this in so, care should be taken to prevent undue breakage.
Lowering the first few truckloads into the hold helps as do control of the rate of tipping down and chute.
Some ports have conveyor belts and an endless bucket system for loading; this is excellent for graded coal and also keeps the dust down with the ordinary coal.
Fortunately it is mainly the better coals, which are graded, and in generally these are not so friable.
Coal will need to be trimmed and its angle of repose is quite high, especially if large coal is loaded.
There is no danger for coal shifting unless it is the very small stuff known as mud coal, slurry or duff.
This is very fine coal, almost dust, and if the moisture content is high it behaves almost like a liquid.
Bulk Cargo (Grain)
Loading and Stowage of Bulk Grain
Before loading bulk the following preparations should be done:
Holds and tween deck thoroughly swept down.
All dunnage removed from cargo spaces or stowed at one and covered.
Bilges should be cleaned and sweetened
Bilges suctions should be tested
Tween deck scuppers should be covered with double weave separation cloth, edges to be fixed with cement.
Any cracks between limber boards to be covered with separation cloth nailed down to prevent the cargo from going into the bilges.
All pipelines passing through the bilges should be tested and any leaks discovered should be fixed – esp. fire mains, water ballast lines and bilge pumping out lines.
After the holds are swept and if required hosed down, the holds/ compartments are to be inspected for any infestation.
The inspection should include all easily accessible areas together with inaccessible areas including under the beams and hatch pontoon frames. In case fumigation is carried out prior loading then the compartment has to be swept and again inspected for any dead insects and rodents. The fumigant used should be compatible with the cargo to be carried.
For loading of Rice the fumigation may be carried out twice – prior loading and on completion of discharging.
The inspection for infestation should be very thorough since apart from later claims, some ports especially in the US, the USDA inspectors would have to clear the ship for loading – and these inspectors are known to be very thorough.
Shifting of cargo
Certain bulk cargos have a tendency to shift and precautions must be taken to counteract this tendency. These precautions are dealt with below:
Recommendation are made about the stowage of the cargo:
Weight = db (3L+B) tonnes
4.6
where d is the summer load draft
b is average breadth of lower hold
L is length of lower hold
B is the maximum moulded breadth
The height of the cargo pile peak should not exceed:
1.89 x d x S. F. (m3/tonne) metres
Angle of repose
This is the greatest angle from the horizontal to which a substance can be raised without it shifting. Cargoes most liable to shift are those having a small angler of repose.
Angle of repose of 35˚ is taken as being the dividing line for bulk cargoes of lesser or greater shifting hazard and cargoes having angles of repose of more or less than this figure are considered separately.
Trimming
In compartments entirely filled with bulk grain the grain shall be trimmed so as to fill all the spaces between the beams and in the wings and ends. In compartments partly filled with bulk grain the grain shall be levelled whenever practicable.
The provision of a shifting boards or longitude bulkheads within 5% of the vessel’s moulded breadth from the centre line or two or more longitudinal bulkheads or shifting boards with a distance between of not more than 60% of the vessel’s moulded breadth. In the latter case suitable sized trimming hatches are to be provided in the wings at intervals of not more than 7.62m., the end hatches being not more than 3.66m from transverse bulkheads.
In holds the shifting boards must extend downwards from the deck at least 2. 44m or ½ depth of hold whichever is the greater. In ‘tween decks and in feeders, unless there is some exemption they must extend from deck to deck. If the compartment is only partly filled with grain, the shifting boards must extend from the bottom of the compartment to at 0.6m above the surface of the bulk grain, however no shifting boards are necessary if the bulk grain does not occupy more than ½ of the hold or ½ of the hold where there is a shaft tunnel.
The Shifting boards must not be less than 50mm in thickness and are to have a 80mm housing at the bulkhead. They must be adequately supported by wood minimum size 250mm x 50mm or metal uprights with a maximum spacing of 3.96mm and set in 80mm housings top and bottom. The jointing of 50mm shifting boards must overlap by at least 230mm in way of the uprights.
If the uprights are made sufficiently strong and the length is not too great, shoring or staying may be unnecessary. If wood shores are used they must be in a single piece securely fixed at each end and heeled against the permanent structure of the ship, but not directly against the side plating. The angle between the shore and the horizontal should be kept as small as possible and must never exceed 45˚.
The size of the shore is dependent upon its length; a shore over 6.1m in length would be at least 200m x 150mm. If stays are used they will be fitted horizontally and will consist of 75mm – 6 x 12 galvanised flexible steel wire rope, secured with 25mm shackles to uprights and frames and fitted with 32mm rigging screws in accessible positions.
If the uprights are not secured at the top, the uppermost shore or stay is to be not less than 0.46m from the top.
The vertical spacing of the shores or stays is obtained from tables in the rules.
If a GM after correction for FSC of not less than 0.31m is maintained throughout the voyage in one or two deck ships or 0.36m in other ships longitudinal bulkheads or shifting boards are not required in the following positions, (except when linseed in bulk is being carried therein)
Below and within 2.13m of a feeder which contains not less than 5% of the quantity of grain in the space it feeds, but only in way a hatchway,
In feeders as above provided that the free grain surface will remain within the feeders throughout the voyage allowing for a sinkage of 2% of the volume of the compartment fed and a shift of the free grain surface to 12˚,
In way of the hatchway where the bulk grain has been saucered, provided that the hatchway is filled with bagged grain or other suitable bagged cargo. The minimum depth of the bagged cargo in the centre of the saucer to be 1.83m below the deck level. The grains to be stored tightly up to the deck head in the other parts of the compartment,
In way of a hatchway in a compartment partly filled with bulk grain.
The surface of grain in a partly filled compartment is to be saucered with a minimum height of 1.52m of bagged grain or other suitable cargo over the portion where there are no
when the bulk grain does not occupy more than 1/3 of the hold or ½ of the hold where there is a shaft tunnel.
The bagged grain shall be carried in sound bags, which shall be securely closed and well filled. The bags or other suitable cargo shall be supported on suitable platforms which consist of strong separation cloths with adequate overlapping or 25mm boards spaced not more that 100mm apart laid on bearers not more than 1.22m apart.
Feeders are to be fitted to feed compartments entirely filled with bulk grain, except in deep tanks not over ½ moulded breadth of vessel in case ‘GM c’ above.
They are to contain not less than 2% of the quantity of grain carried in the compartment, which they feed. The boarding may be horizontal or vertical but must be sufficiently supported by binders, shores or stays as laid down in the rules. Feeding holes are to be provided about 0.61m apart in coamings, which extend more that 0.39m below the deck. The diameter of the hole is 50mm or 88mm depending on coaming depth. Feeders are assumed to be capable of feeding a distance of 7.62m.
If any part of the compartment is more that 7.62m (measured in a fore and aft line) from the nearest feeder, the grain in the space beyond 7.62m is to be levelled off at a depth of at least 1.83m below the deck and the space above is to be filled with bagged grain or suitable cargo.
Loading two different cargoes in the same hold
Very occasionally, different types of grain are loaded into the same hold. The heavier grain is loaded first and trimmed level over the entire area of the hold. The surface is covered with separation cloths/ canvas, allowing for ample overlaps, at least 1m. The cloths are carried well up the sides and ends of the compartment so that the next grain loaded will force them against the plating between the frames and stiffeners, it has to be ensured that adequate leeway is allowed for the separation cloth being taken up the sides and ends of the
compartment, since the lower cargo would settle down during the voyage and if this leeway is not allowed for the cloth would exert a pull and tear off from the side moorings. This would result in the cargo being mixed.
The lighter grain should be loaded carefully at first to avoid displacing the separation cloths. Once the lighter cargo has been leveled off to a height of 0.5m all over the loading may begin at the usual rate, care being taken to see that it is constantly leveled by adjusting the loading chute inflow direction.
When bulk grain is carried in the ‘tween deck of a two deck ship or in the upper ‘tween deck of a ship having more than two decks or above deck the following are to be complied with:
Either the GM shall not be less than that specified in paragraph ‘GM’ or the total quantity of bulk grain or other cargo carried in the specified space shall not exceed 28% by weight of the total cargo below the ‘tween deck.
Partly filled deck area in the above space is not to exceed 93m2,
The spaces which contain bulk grain are to be divided into lengths of not more than 30.5m by transverse bulkheads, or if not so divided the excess space – beyond 30.5m is to be entirely filled with bagged grain or other suitable cargo.
Vessels having a GM less than that specified in paragraph ‘GM’ are not permitted to have more than two holds or compartments partly filled with bulk grain wherein the overstowing cargo does not fill the space to the deck head. Feeders are not compartments and so they are exempted from this requirement.
Double bottom tanks used to meet a stability requirement are to be adequately subdivided longitudinally unless the width of the tank at its ½ length does not exceed 60% of the vessel’s moulded breadth.
A grain-loading plan may be supplied to certain ships, which may then be exempted from some of the provisions outlined above due to their special construction (such as tanker and bulk carriers), which prevents shifting of the bulk cargo. However, the resulting list of the vessel must not exceed 5˚ if the grain settles by 2% and shifts to an angle of 12˚ from its original position.
Cargo Care
Inspection of Holds prior Loading:
All holds should be inspected prior commencing loading this may be done while the ship is enroute or just after completion of discharging and prior loading at the same port.
