Well decks are exposed decks, lower than the decks immediately fore and aft. On vessels with fo'c'sle decks forward and poop decks aft, a well deck is formed at midships. Traditional ocean liners often had well decks fore and aft of the superstructure, where the deckline has been lowered to accommodate lifting devices and hatches for the cargo holds. Many rescue boats have also prominent wells with minimal freeboard to aid rescue operations which may be circumstantially referred to as well decks, though they are more correctly simple wells.
Well decks require care to ensure adequate freeing arrangements as decks above will have a tendency to shed water down, and they often (also - by some definitions) have bulwarks. The lowering of the freeboard deck through the well also reduces reserve buoyancy, which may have a detrimental effect on stability. Well decks do, however, lower the weight of a vessel, provide a closer access to the waterline for lifting devices or working overboard, and more protection from the elements than a flush-deck vessel of the same depth. In general, the benefits and caveats of both poop decks and fo'c'sles will apply.