Orlop deck

The orlop is the lowest deck in a ship (except for very old ships), immediately above the hold. It is the deck or part of a deck where the cables are stowed, usually below the water line.^[1]

18th century warship cross section, the orlop deck highlighted in red

The orlop of the Swedish 17th century warship Vasa looking toward the bow.

The word derives from the Dutch overloop from the verb overlopen ("to run over, extend").^[2]

References

1. Keegan, John (1989). The Price of Admiralty. New York: Viking. p. 279. ISBN 0-670-81416-4.
2. "Orlop" from Shorter Oxford English Dictionary