A chronological record of all maintenance work carried out on hatch covers and coamings must be maintained. It could be required as evidence to defend cargo claims.
All Hatch Covers are to be hose tested prior each loading (containerships excepted) and the cause of the leakage, if any to be ascertained and rectified. Special care must be taken to check the tightness of the center joint. Records for hose testing are to be made in the Deck Log Book.
Often surveyors may use ultrasonic testing equipment for checking the hatch cover tightness. Please ensure that all the cleats are secured and correctly adjusted.
Ensure that all coaming and cross joint channels and drains are clear. Non-return ball valves where fitted, on coaming drains, should be maintained operational.
Check if the sealing surface is not lodged with cargo residue or any other foreign material.
Inspect the rubber packing for breakage, hardening or permanent set in way of compression bar and ensure the cross joint tightness with minimum clearance in the athwart centering locators.
Check compression bar surface for damage due indentation or rubbing. Check coaming, main deck cross strip for deformation, if any. Carry out chalk test on the suspected area or the entire sealing face.
The concerned locating wedge may then be renewed / built up ensuring that the rubber packing is not compressed beyond the permissible limit.
Resting pads must be checked to ensure that the packing is not compressed beyond maximum limit.
Rest pads take the weight of the pontoon. Excessive thinning down of the pads will cause the packing to be compressed beyond maximum permissible limit causing a permanent set and in worst cases the packing to be torn / the hatch cover skirt plate cutting into the coaming table top plate.
Always ensure cleats are removed positively before opening the hatch covers.
The cleating arrangement is to be maintained in good working order and should be adjusted periodically.
All rollers, wheels, idlers, and sheaves must be kept free and well lubricated. The bushes must be checked for wear. Cargo dust, sand blasting grit, dried grease or rust must not be allowed to set in. This increases the operating resistance considerably.
For the chain operated covers, the hydraulic system would have to work against a considerably high added resistance, if a chain was to be dragged along a seized sheave, rather than being rolled; also if the pontoon had to be dragged out rather than being rolled out.
The track way must be examined for deformation and wear. All wheels must make rolling contact with the track way.
Hatch Covers on Combination Carriers
The hatches on combination carriers, when carrying liquid cargo, must be maintained gas and liquid tight at all times.
When closing the hatch covers, the closing devices should be evenly and progressively pulled down in the correct sequence in accordance with the manufacturer’s instructions.
In ship’s fitted with inert gas or fixed high-capacity gas freeing systems, a positive test of the efficiency of the sealing arrangements can be carried out by pressurizing the holds and applying a soapy solution to the sealing arrangement.
Any leakage is readily detectable and should be rectified by further adjustment of the closing devices in the affected area.
The cover joints should be examined for gas leakage when the compartment is loaded with liquid cargo and any gas or liquid leaks, which cannot be stopped by adjusting the closing devices, should be marked or noted so that the joining material can be examined when the opportunity arises and the joint made good. Additional sealing by means of tape or compound may be necessary.
The hatch seals should be examined whenever a suitable opportunity occurs. It is also advisable to have on board a reasonable stock of joining material of the correct size so that the repairs can be carried out.
Hydraulic System for Hatch Cover
The hydraulic system is to be maintained clean at all times. The line filters and the tank filters are to be cleaned as per Annex 1 or more frequently if required.
The return line filter to be examined for metal fines, to monitor the wear and tear in the hydraulic pumps and motors.
The lubricating oil should be sent ashore for infra-red spectroscopic analysis for “particle count test” every six months.
The hydraulic tank is to be cleaned internally once a year and examined for sludge deposits / metal particles.
The system working pressure is to be monitored regularly and compared with the specification. The pressure is not to be increased without the consent of Chief Engineer. When increased resistance is observed in hatch cover operation, the cause should be ascertained at the first opportunity and rectified on priority.
When commencing operation of pumps, ensure that each pump is developing the required pressure.
Care must be taken to avoid cargo dust, grit etc. from depositing on the rams of the hydraulic jacks and shafts of the hydraulic motors. The chrome plating of these surfaces to be protected from corrosion and pitting to maintain the sealing surface oil tight. When not in use, these must be covered with waterproof canvas. The dust seals for the jacks should be checked periodically and maintained in good order.
The flexible high-pressure hoses must be maintained and protected from rubbing against the moving parts. Essential spare hoses must be identified and kept as spare.
Hydraulic lines and pressure couplings on deck must be prevented from corrosion and all leakages must be rectified immediately.
Sufficient spares are to be maintained to ensure that repairs can be handled effectively and promptly.
Timings for hatch cover operation (opening and closing) is to be recorded every four months and to be included in the 4-Monthly Report sent to the office. Same to be compared with previous readings and Maker’s specified speed. Any deterioration in the performance is to be brought to the notice of the Superintendent. The system is to be thoroughly checked for the cause of speed reduction of the concerned hatch cover and attended on priority.
Emergency Operation of Hatch Covers
Emergency operation of the hatch covers should be carried out every six months, and concerned officers / crew trained.
Reference is to be made to IACS guidelines “Care of Hatch Covers” for more information and understanding.
