How to avoid bulk carriers structure damage during cargo operation ? (2024)

a) Grab evenly over the full area of the hold to avoid development of steep banks in the wings.

b) Avoid pendulum swinging of the grab into the wings so that it will not strike the ship's side shell frames.

c) Grab should be straight and parallel to the ship's side.

d) Do not land the grab on the hopper side where bare steel is visible.

e) Do not attempt to land the grab close to the foreward and after bulkheads, as there may be an outward sloping stool plate under the cargo.

f) Operate grab from the highest point of the cargo at all times.

g) Any damage to the frames may affect the seaworthiness of the ship, and has to be reported to the master.

h) Avoid swinging the grab in at an angle, as the corner of the grab may strike the hopper tank first. This will cause heavy indents or puncture holes in the tank plate.

Prevention of damage to inner bottom plating (tanktop)

Lower the grab carefully and evenly on to the tank top. Never drop the grab at speed. Be particularly careful where there are mounds of cargo on the tank top. One side of the grab will land safely on the cargo but the other side may drop corner first on to bare steel. If it lands heavily it can puncture the tank top.

Prevention of damage to hatch coamings and covers

The operator should always check along the line of hatches that the covers are completely opened clear of the coaming. The travel of the grab into the hold should be controlled so that the grab and the grab trolley are in line as the grab is moving out and down into the hold. This will ensure that the swing is under control at all times.

When working in the wings the grab trolley should be positioned so that the grab ropes and the grab itself are raised clear of the coaming.

This is caused by grab or rope contact with the coamings or covers. Ship's crew may:

Leave covers slightly closed over the top of the coaming to prevent spillage getting into the drain channels.

Fail to secure the open covers in place, which can allow them to roll closed.

Always be aware that the ship can move in or out, fore and aft, and up and down due to wind, tide, movement of cargo and ballast, or crew adjusting mooring ropes.

Raising or lowering the grab close to the coaming may result in the grab or the grab rope shackles catching on the lips of the hatch cover. This will result in the cover being lifted and dropped heavily, causing major damage to the coaming, the cover and the cover drive mechanism.

Damage to the cross-joint sealing arrangement could also occur.

Prevention of damage by payloader to bottoms of ladders, stool plates and bulkheads ­

In co-ordination with the master, the operator should be informed of:

Location of the bottoms of ladders.

Location of any pipes or pipe guards.

Location of bilge covers plates.

Payloader drivers should:

Operate carefully around ladders and projections. Remove material manually where necessary.

Avoid grinding the corners of the payloader bucket along the bottom of the bulkheads and hopper tanks, as this kind of heavy pressure can cause unseen damage.

The master should point out the position of any obstructions on the tank top. On some ships the locations of bilge cover plates are marked by a line of paint on the bulkhead.

Prevention of damage to deck fittings and equipment

Before travelling the unloader to a new location.

Check that the grab is well clear of all deck fittings and equipment before moving.

Check that it is clear for the unloader to long travel.

When working close to the bridge front or foremast make due allowances for aerials and other obstructions to the unloader boom and keep well clear.

Geared Ships:

Derrick and crane jibs not in use should be lowered below the level of the unloader boom.

As the ship rises up as the cargo is unloaded, the unloader operator should always check that there is safe clearance over all obstructions before attempting to move the unloader. The unloader boom should always be raised before moving if there is any doubt.

Error inducing conditions

The following conditions may lead to operator error or misjudgement:

Overfilled or unevenly filled holds having ladders and platforms buried under the cargo.

Environmental conditions ­ poor lighting, dust, glare, fog.

Mechanical or control problems on the unloader ­ faulty grab controls, slipping winch brakes, slipping long travel brakes.

Poor working conditions such as poor conditions in the operator cab, faulty indicators, inadequate means of communications with ship and/or co-workers, faulty seat, dirty windows.

Never grab from the foreward and aft ends of the holds without being sure of where the ladders are.

Do not work unless the cargo in the hold is clearly visible.

All equipment faults should be reported to the terminal representative or relevant maintenance person immediately.

Unloader operation is a demanding job that requires concentration and care. Deficiencies and problems that distract the operator should be rectified immediately.

Top articles