Hatch covers are arguably one of the most important items that require optimal performance when it comes to the safe transportation of cargo. The hatch cover is not only an important component of load line items on board, but it also guarantees that cargo is transported safely and securely so that cargo claims are kept to a minimum. Let’s take a look at some of the most important things that you should never ignore when it comes to Hatch covers.
Permanent setting down of gaskets
If you think the seal will be tighter by default then you are wrong. The hatch cover closes with steel to steel contact. For a newly installed hatch cover, with new packings and new gaskets, it is very difficult to achieve gasket compression over 25-30%. In short, if you have achieved a solid steel to steel contact then nothing can be gained by over tightening cleats. Over tightening will only result in permanent gasket compression and nothing else. Losing the sealing property is also a result of over tightening. When contact faces of steel wear out which is quite common in older ships, then there is no point in renewing the gasket. It is not possible to renew the gasket until the entire depth of steel is re-built. Please note that gaskets have a specific lifespan and should be inspected and renewed accordingly.
Damaged or corroded compressions
Compression bars should always be inspected for damage, such as buckling, cracking and unevenness. Compression bars are always repaired by runs of welding and buffing to achieve an even and smooth finish. The most effective way to prevent compression bar damage is to fully open the hatch cover to prevent damage from crane wires and grab while working on cargo in the hold.
Damaged retaining channels
The typical thickness of gasket retaining bars is 8mm. This makes them prone to corrosion over time. The issue arises when the retaining channels aren’t in good condition. The gasket won’t retain its desired cross section, and there’s a risk of leakage.
Blocked drain holes and pipes
It’s one of the reasons so many perishable cargo claims have been made in the past. Blocked drains, channels or pipes would almost always cause water to overflow over the cargo spaces rather than just draining out.
Hatch coamings and in between space must be cleaned as a routine before closing and securing the hatch. They should also be kept painted.
Cleats are designed to resist the dynamic forces of the hatch cover. Depending on the hatch cover, the design of the cleats may differ. Cleats are subjected to heavy use and heavy wear and tear. They should be regularly checked and properly adjusted. Spare cleats should be kept ready. Neoprene washers should be renewed once they have lost elasticity and are found to be deformable.
All of this should be done as part of your initial inspection. Any defects you notice will be added to your defect list and your work plan will need to be chalked off accordingly after you have ordered for the appropriate spares. Always consult your Hatch Cover Maintenance Manual or Original Manufacturer when in doubt, as part of your hatch cover testing routine.