What to check on a Pontoon Hatch Cover.
A pontoon hatch cover is a set of separate rectangular steel panels, each lifted individually by crane using lifting eyes or a spreader beam, and stowed on deck or ashore while the hold is open. It has no rail, wheel or hinge mechanism of its own, which makes it mechanically the simplest hatch cover type and the easiest to repair or replace panel by panel. The trade-off against side-rolling or folding covers is opening speed and independence from lifting equipment: a pontoon cover cannot open itself, it needs a crane…
What Sets a Pontoon Cover Apart
A pontoon hatch cover is a set of separate rectangular steel panels, each lifted individually by crane using lifting eyes or a spreader beam, and stowed on deck or ashore while the hold is open. It has no rail, wheel or hinge mechanism of its own, which makes it mechanically the simplest hatch cover type and the easiest to repair or replace panel by panel. The trade-off against side-rolling or folding covers is opening speed and independence from lifting equipment: a pontoon cover cannot open itself, it needs a crane of adequate capacity and reach at every port, whereas rolling and folding types are self-contained. Pontoon covers remain common on older general cargo tonnage, on vessels where deck space for stowing rolled panels is limited, and on some heavy-lift and project vessels where individual panel removal actually suits the cargo-handling plan.
Main Components
Pontoon panels
Stiffened steel plate panels, each sized to be within the lifting capacity of the vessel's or terminal's cranes, forming the full hatch cover when placed side by side across the coaming.
Lifting eyes / spreader beam interface
Fixed lifting points on each panel engage either ship's crane hooks directly or a dedicated spreader beam that lifts several panels in a coordinated set, reducing the number of individual lifts.
Coaming seating and compression bar
Each panel seats onto a rubber gasket around the coaming edge, held down by cleats or a compression bar tightened after the panel is landed, rather than a continuous hydraulic cleating system running the length of the hatch.
Tarpaulins on older, non-weathertight designs
Some older pontoon arrangements rely on tarpaulins and battens over the panels for weathertightness rather than a gasket seal built into the panel itself; this design is largely obsolete but still found on older tonnage.
Selection and Sizing
Sizing centres on matching panel weight to available lifting capacity rather than on a self-contained opening mechanism:
- Individual panel weight against the crane or spreader beam capacity available at the ports the vessel actually calls
- Panel count and layout across the hatch width, balancing fewer heavy panels against more numerous lighter ones
- Steel grade and coating for the panel and coaming interface, given repeated crane handling and green-sea exposure
- Gasket-sealed versus tarpaulin-and-batten weathertightness, which affects both maintenance and survey outcome
Regulations and Class
Pontoon covers are subject to the same Load Line Convention and IACS Unified Requirement scantling and weathertightness standards as other hatch cover types, and are surveyed on the same periodic schedule for compression seal condition, either by hose test or ultrasonic testing where gasket-sealed. Where tarpaulin-and-batten covers are still fitted, class rules set minimum numbers of tarpaulin layers and batten securing arrangements, and this design is increasingly scrutinised at survey given its higher risk of green-water ingress compared with gasket-sealed panels.
Typical Faults
| Fault | Cause | Consequence |
|---|---|---|
| Distorted or dented panels | Rough handling during crane lifts, cargo impact | Poor gasket seating, localised leaks even after cleats are tightened |
| Corroded lifting eyes | Salt exposure, lack of inspection since the eyes see load only during opening | Lifting point failure during a crane lift, dropped panel |
| Perished gasket or degraded tarpaulin | UV exposure, age, cargo residue on the seating | Water ingress into the hold and cargo wetting |
| Missing or loose battens (tarpaulin type) | Poor securing after cargo operations, inconsistent crew practice | Tarpaulin lifts in heavy weather, direct water ingress |
What to Look for in a Supplier
- Confirmed panel weight against both the ship's own crane capacity and the terminal cranes the vessel typically uses
- Certified lifting eye load rating with test certificates, since these points carry the full panel weight on every operation
- Gasket material suited to the trade and available as a stocked replacement item, not a special order
- Willingness to supply individual replacement panels rather than requiring a full-set order after localised damage
Inspect lifting eyes at every cargo operation, not just at survey — they take full panel load dozens of times a voyage and corrode quietly in a position nobody looks at once the panel is landed.