Hatch cover arrangement for general cargo ships - Handling precautions
How to make watertight
Hatch covers are used to close off the hatch opening and make it watertight. Wooden hatch covers, consisting of beams and boards over the opening and covered with tarpaulins, were once used but are no longer fitted.
Steel hatch covers, comprising a number of linked steel covers, are now fitted universally. Various designs exist for particular applications, but most offer simple and quick opening and closing, which speed up the cargo handling operation.
A MacGregor single-pull weather-deck hatch cover is shown in Figure. The hatch covers are arranged to move on rollers along a track on top of the hatch coaming. The individual covers are linked together by chains and ride up and tip onto a stowage rack at the hatch end. A hydraulic power unit, operated from a control box at the hatch end, is used to open and close the hatch cover. It is possible to open and close the covers with a single wire pull from a crane or winch.
Watertigtitness of the closed covers is achieved by pulling them down on to a compressible jointing strip. This is done by the use of cleats which may be hand-operated or automatically engaged as the hatch closes. Hatch covers below the weather decks are arranged flush with the deck. In the arrangement shown a self-contained hydraulik power pack with reservoir pump and motor is mounted into a pair of hatch covers. This power pack serves the operating cylinder for the pair of covers. Control is from a nearby point and hydraulic piping is reduced to a minimum.
Maintenance requirements for this equipment are usually minimal but regular inspection and servicing should be undertaken. Most hatch covers can, if necessary, be removed manually. The means of securing the hatches and maintaining their watertightness is tested initially and at periodic surveys.
Any hatch covering used on a ship is to be of sound construction and material, of adequate strength for the purpose for which it is used, free from patent defect and properly maintained.
A hatch covering is not to be used unless it can be removed and replaced, whether manually or with mechanical power, without endangering any person. Information showing the correct replacement position is to be clearly marked, except where hatch coverings are interchangeable or incapable of being incorrectly replaced.
A hatch is not to be used unless the hatch covering has been completely removed, or if not completely removed, is properly secure.
Before vessel departure, weather deck hatch covers should be secured in the correct closed position. Whilst the vessel is at sea they should be regularly inspected to ensure that integrity is being maintained.
All hatch covers should be properly maintained. Defective or damaged covers should be replaced/repaired as soon as possible. All covers and beams should only be used if they are a good fit and overlap their end supports to an extent which is adequate but not excessive.
All personnel involved with the handling and/or operation of hatch covers must be properly instructed in their handling and operation. All stages of opening or closing hatches should be supervised by a responsible person. When hatches are open, the area around the opening and in the hatchways should be appropriately illuminated and guard-rails erected. Guard-rails should be tight with stanchions secured in position, and properly maintained. No hatch cover should be replaced contrary to information showing the correct replacement position.
Where lifting appliances are used, they should be attached to hatch covers from a safe position and without personnel being exposed to the danger of falling or being trapped.
No loads should be placed over, nor work take place on, any section of hatch cover unless it is known that the cover is properly secured and can safely support the load. Partly opened unguarded hatches should never be covered with tarpaulins; this would present a serious hazard for any person walking across the hatch. Hatch covers should not be used for any other purpose.
During operations, personnel should keep clear of the hatches and the cover stowage positions. The area should be kept clear of all items which might foul the covers or the handling equipment.
Special attention should be paid to the trim of the vessel when handling mechanical covers. The hatch locking pins or preventers of rolling hatch covers should not be removed until a check wire is fast to prevent premature rolling when the tracking is not horizontal.
Hatch wheels should be kept greased and free from dirt and the coaming runways and the drainage channels kept clean. The rubber sealing joints should be properly secured and be in good condition so as to provide a proper weathertight seal.
All locking and tightening devices should be secured in place on a closed hatch at all times when at sea. Securing cleats should be kept greased. Cleats, top-wedges and other tightening devices should be checked regularly whilst at sea.
Hatch covers should be properly secured immediately after closing or opening. They should be secured in the open position with chain preventers or by other suitable means. No one should climb on to any hatch cover unless it is properly secured.
Unless hatches are fitted with coamings to a height of at least 760 mm (30 inches) they should be securely covered or fenced to a height of 1 metre (39 inches) when not in use for the passage of cargo. Inspection/access hatch lids should be constructed of steel or similar material, and hinged so they can be easily and safely opened or closed. Those on weather decks should be seated on watertight rubber gaskets and secured weathertight by adequate dogs, side cleats or equivalent tightening devices.
Except in the event of an emergency endangering health or safety, no person should operate a hatch covering which is power-operated or a ship's ramp or a retractable car-deck unless authorised to do so by a responsible ship's officer.
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