The orlop deck
is the lowest deck
in a ship
(except for very old ships). It is the deck or part of a deck where the cables
are stowed, usually below the water line. It has been suggested the name originates from "overlooping" of the cables.
It has also been suggested that the name is a corruption of "overlap," referring to an overlapping, balcony-like half deck occupying a portion of the ship's lowest deck space.
Anatomy of sailing ships