Hatch

A closable opening that provides access, light or ventilation through a deck, cabin top or bulkhead.

A hatch may be horizontal, inclined or vertical and can lead to accommodation, machinery, storage or an escape route. Its cover may lift, slide or be removed, and a raised coaming commonly helps limit water entry on exposed openings.

Watertight, weathertight and merely splash-resistant hatches are not interchangeable descriptions. Seals, glazing, hinges, dogs, drains and coamings require inspection, and an open hatch creates both a flooding route and a fall hazard unless managed for the conditions.