Weathertight Door

A weathertight door prevents water from passing through it in any sea condition, but unlike a watertight door it is not designed to resist a sustained static head from a flooded compartment. Weathertightness is defined in the Load Lines Convention and applied through SOLAS II-1 to openings in exposed positions above the freeboard deck, such as deckhouse and superstructure access doors. Gasketed steel doors with dogs or quick-acting cleats, set on coamings of the required height, keep water out under boarding seas and spray. They protect reserve buoyancy and the assigned freeboard. Watertight doors, by contrast, are governed by II-1/13 for subdivision integrity.