Hatch cover technical details Sealing solutions Lift-away hatch covers can be either weathertight or non-tight. Non-tight panels are permitted for use on large container ships, while the hatch covers on smaller ships need to be weathertight. Weathertightness between hatch covers and coaming is generally achieved by a sliding seal, which is fitted to the panels and tightens against the top of the coaming. Sliding seals can be fitted to the panel joints, enabling both sequential and non-sequential operation. In the case of non-weathertight hatches, a labyrinth-type gasketless seal and/or an open joint without drainage can be used. A sliding seal can be used between panels, especially for two-panel solutions. The non-weathertightness of covers – or reduced weathertightness for some class requirements – should be clarified, in all cases, with classification societies, national authorities and the shipowner with reference to IACS LL64 regulations.
The covers can be operated sequentially or nonsequentially, depending on the type of cross-joint chosen. A sequential joint with sealing can be used in basic solutions where there is no need to specify partial opening of the hold. This type of joint is fitted with cleating. Pneumatically-operated Omega seals are used for weathertight non-sequential operation. Omega seals operate using the ship’s compressed air system. Reduced weathertightness can be accepted on a caseby-case basis for large cellular container ships. Sealing is achieved by fitting longitudinal joints with double rubber lip seals that prevent rain and spray entering the hold. No manual operation is needed for double rubber lip seals during hatch cover operation. Seals need to be hosetested to a class surveyor’s satisfaction. Non-weathertight hatch covers can use an open joint.
Sequential joint
Sliding joint with C-gasket
Omega joint
Double rubber lip seal
Open joint with drainage
Open joint, no drainage
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