2.1 Recent research has quantified the magnitude
of sea load pressures acting on the side and end faces of hatch covers
and on hatch coamings. This has revealed substantial green sea loading
pressures which may generate lateral forces well in excess of the
capability of some hatch cover securing devices. These forces cause
significant loading on hatch cover travel stops and securing devices,
and are only partially resisted by frictional and cleating forces.
2.2 The strength of securing devices of hatch
covers on all ships should therefore be reviewed by the Administration.
The review should ensure that the weathertightness of each cover is
not likely to be impaired having regard to the service in which the
ship is engaged and the location of the hatchway. Where hatch covers
or coamings undergo substantial repair, the strength of securing devices
should be brought up to the relevant standard for new construction.
2.3 Hydraulic cleating systems are generally preferable
to manual cleats from the operability standpoint on large hatch covers.
Where hydraulic cleating is used, the system should be protected against
release by incorporating mechanical securing devices. IACS Recommendation
14 contains such guidance.
2.4 The cleating and securing devices should be
designed or otherwise arranged to be readily visible, so as to facilitate
checking proper and complete securing of hatch covers during a voyage.
2.5 Manufacturers should provide recommendations
on the safe operation, inspection, maintenance and repair of each
type of hatch cover fitted, with a recommended list of spare parts
to be carried aboard. This guidance should include recommendations
for the periodic renewal of components subject to wear or ageing.
A maintenance record sheet should also be provided to document owner's
inspections and maintenance planning in accordance with the International
Safety Management Code (ISM Code).