Britannia P&I Club has published an article to inform interested parties how to maintain hatch covers properly, in order to avoid claims related to water ingress.
ccording to Britannia, the lack of hatch cover maintenance and/or improper repairs to hatch covers has been shown to be the primary cause of water ingress into the cargo holds which can lead to cargo damage. In addition to the financial and insurance claims, there are other potentially more serious consequences that need to be considered:
- Fire – is the cargo being carried likely to self heat or combust when wet?
- Accelerated corrosion – is the cargo being carried reactive to moisture (e.g. sulphur)?
- Loss of stability – is the cargo being carried prone to liquefaction when wet?
- Any one of the above could potentially lead to the loss of the vessel and possible loss of life.
General maintenance and routines
Continuous monitoring of the condition of the hatch covers and their sealing arrangements is best done when the covers are being opened and closed during operations. This continuous monitoring serves as an early warning and hopefully will prevent the development of more serious problems.
The following is a list of the common defects found during ship inspections and cargo damage investigations. This list is by no means exhaustive, it is a list of inspection and maintenance items that should form part of the ship’s regular routine.
- Before closing the hatch covers, ensure that the hatch coamings and double drainage channels are swept clean of any cargo debris. This will ensure that the coaming drain non-return valve remains clear and free as well as ensuring that no damage occurs to either the hatch cover rubber packing or the compression bar. It will also ensure that there is no obstruction to the correct and proper sealing of the hatch cover.
- Whilst cleaning, check for any damage to the coaming area, paying particular attention to the compression bars, wheels, wheel tracks and landing pads. Record details of any damages found for urgent or future remedial repairs as required. If temporary repairs are required, it must be ensured that these temporary measures are such that the ship’s cargo worthiness will not be affected for the entirety of the voyage. Ensure that the moving parts (wheels, cross joint hinges, hydraulic ram bearings etc.) are greased at regular intervals.
- If the hatch cover design is such that the cover side panels and end plates are in ‘steel to steel’ contact with the hatch coaming tops when in the closed position, check whether the coaming tops are free from grooving or wear. This would indicate worn hatch sealing rubbers.
- Hatch cover landing pads should be maintained in a good condition at all times, ensuring that any corrosion is dealt with in a timely manner and that the pads are greased regularly.
- Grooved , corroded or worn down landing pads are to be either built up with welding and ground back to original dimensions or cropped off and replaced in their entirety.
- Check for any rust streaks on the inside of the coaming which would indicate water ingress from leaking hatch cover seals. Take remedial action and repair the seal and clean off the rust streaks.
- Check and clean the surface of the seals. This is particularly important if the cargo being carried is gritty or dusty.
- When cleaning the seals, check for signs of permanent deformation (a useful general rule is 30% of the seal thickness). If sections of sealing rubber are required to be replaced, the minimum length is 1m. However, it is often better to replace a full length of sealing rubber to ensure effective and even compression.
- Hold access hatches and ventilation covers need to be carefully scrutinised in the same manner as the hatch covers themselves, for signs of damage to the sealing areas, securing arrangements etc.
The function of the cleats is to keep the hatch covers in position and maintain the seal’s design compression. The excessive tightening of cleats will not improve weather tightness but will lead to the accelerated wear of the seals and the landing pads and could even distort the hatch cover. Cleats and their snugs should be inspected for any damage, ensure the rubber washer is intact and not perished and the tightening nut is free to move.
- Standard adjustment of the hatch cleats is to tighten the nut hand tight against the steel washer and then to further tighten by 360 degrees.
Hauling wires/chains need to be inspected for correct adjustment and tension to avoid uneven seating and hatch cover distortion when closed.