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Maintenance procedure for steel hatch covers of seagoing bulk carrier
Types of hatch covers will vary depending upon the construction of the vessels, and they form a major part of the vessel's watertight integrity and therefore, require a lot of attention. The following are guidance notes which apply to most types of hatch covers, and are to be used in conjunction with manufacturer's instruction manuals and any additional information held on board specific to the type of hatch covers fitted.
Hatch covers are to be inspected prior to loading.
Undersides of Hatches
Whilst it is fully appreciated that access to the underside of hatch covers for maintenance purposes is difficult, you are requested to carry out such maintenance to the best of your abilities, with consideration to the type of hatch covers fitted to your vessel. Any scale or flaking paint on the undersides will inevitably end up on top of the cargo, especially during opening and closing operations when such scale and paint flakes are liable to be vibrated free of the hatch cover.
Fig: Bulk carrier sliding hatch cover
Sealing rubbers are to be inspected for damage, distortion, cracking and over compression, which can result in deterioration of elasticity and poor sealing. At the points where the rubber sections are joined, gaps may begin to appear. If this occurs it is to be remedied as soon as it is discovered.
The rubbers must be smooth and free from rust particles and paint flakes, possibly picked up from hatch coamings. If the rubbers have deteriorated due to age, the relevant Management Office is to be notified with a report on the extent of such deterioration. Poor sealing can often be remedied by insertion of an extra rubber lining underneath the main sealing rubber to increase the compression and provide a better seal.
Compression bars must always be kept smooth, free from rust and paint, and any damages must be repaired immediately. The areas immediately surrounding the compression bars are to be swept clean of any cargo residues after loading/discharging operations, to ensure that no distortion of rubbers, and retainer channels takes place when the hatch cover is closed.
Securing dogs must always be used while the vessel is at sea. They must be well maintained and greased, and are to be checked on a regular basis.
Drain Channels are normally inaccessible after the hatch cover has been closed, and are therefore to be attended and checked immediately after loading/discharging operations have been completed. If any obstructions are present, water will be permitted to build up and overflow into the cargo hold. The channels must be swept clean of any cargo residues, and are always to be free of rust, scale and flaking paint. Loose items, such as these, will be washed into the coaming drains and causes blockages which result in accumulation of water and eventual overflow into the cargo hold.
The non-return drain facilities on the hatch coamings must always be kept clear. They are most susceptible to blockage during loading/discharging operations, and must be checked and cleared after completion of such operations. The condition of the non-return facility must be checked frequently to ensure optimum operation and prevention of water ingress during heavy weather.
Hatch Cover Openings
The following type of hatch cover openings are common place on board bulk carriers;
- coal vents,
- natural vents,
- forced draft fan cowlings,
- cement feeder lids
- inspection hatches.
All these types of openings involve some kind of seal and securing devices which must be checked on a regular basis. Securing dogs/bolts must always be free and greased, ready for immediate operation. Some openings, such as cement feeder lids, which have not been brought back into use after a long period of time may best be left undisturbed if reliably known to be fully watertight following a hose test. However, if the seal has perished due to age, it must be renewed immediately. This also applies to hold access hatches.
Hatch Sealing Tape
It is the Masters responsibility to maintain an adequate supply of Hatch sealing tape on board at all times, and to requisition for supply as required. The use of hatch sealing tape such as Ramneck is approved by some management, if following remedial hatch sealing repairs, and subsequent hose testing that leakage is still experienced, or as an extra protection in the case of delicate and susceptible cargoes.
Fig:Steel hatch cover arrangement on a bulk carrier
The machinery and associated equipment required for the opening and closing of hatch covers, must be kept in good working order at all times and any defects which may hinder the operation and cannot be rectified immediately by ship's Officers and Crew, must be notified to the relevant Management Office immediately.
Damage to cargoes are common due to defects which delayed the closing of hatches during rain. Claims from Charterers have also been common place for time lost, due to an unacceptable time being required to open/close hatches as the result of opening and closing systems not operating correctly.
Where hydraulic systems are employed, care must be taken to avoid leakage of hydraulic fluid which would cause hazardous conditions on the vessel's deck and possible injury to ship and shore personnel. Many delays and resultant loss of hire have been caused through shore personnel and port officials refusing to board the vessel due to hydraulic fluid on the vessel's deck. It has also been the cause of fines for pollution when such fluid has escaped over the ship's side.
Tests and Inspections
Due frequent claims for cargo damage by water ingress through hatch covers owing to poor seals, it is wise to chalk test all hatch seals prior to loading cargo. This must be followed by hose testing of all the holds to ensure that all the seals are effective and that no water is entering the holds. A report on the findings is to be forwarded, as soon as possible after the tests have been carried out, to the relevant Management Office.
Any defects must be rectified immediately and certainly before commencement of loading or inspection by Charterers or shore personnel. Any assistance required to carry out this task must be notified immediately to the Company.
Steel hatch cover testing guideline
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Operation of sea going bulk carriers involved numerous hazards . Careful planning and exercising due caution for all critical shipboard matters are important . This site is a quick reference to international shipping community with guidance and information on the loading and discharging of modern bulk carriers so as to remain within the limitations as specified by the classification society.
It is vital to reduce the likelihood of over-stressing the ship's structure and also complying with all essential safety measures for a safe passage at sea. Our detail pages contain various bulk carrier related topics that might be useful for people working on board and those who working ashore in the terminal. For any remarks please Contact us
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