Well deck

This article is about the traditional use of the term "well deck". For well decks in amphibious warfare ships, see Well dock.

In traditional use well decks were decks lower than decks fore and aft, usually at the main deck level, so that breaks appear in the main deck profile as opposed to a flush deck profile. The term goes back to the days of sail. Late 20th Century commercial and military amphibious ships have applied the term to an entirely different type of hanger like structure, evolving from exaggerated deep "well decks" of World War II amphibious vessels, that can be flooded for lighters or landing craft.

Traditional

USS William Ward Burrows (AP-6) on 6 July 1942. Her 3"/23 guns have been replaced with 3"/50 guns and the sponson in the forward well deck for the 50-foot motor launches has been removed. (The aft well deck is clearly visible forward of the poop.) Navy photo collection Photo No. 19-N-32040

A well deck is an exposed deck (weather deck) lower than decks fore and aft. In particular it is one enclosed by bulwarks limiting flow of water and thus drainage so that design requirements are specific about drainage and maintenance of such drainage with that definition applying even to small vessels. The United States Coast Guard, Sector Upper Mississippi River, Small Passenger Vessel Information Package notes:

"Well deck" means a weather deck fitted with solid bulwarks that impede the drainage of water over the sides or an exposed recess in the weather deck extending 1/2 or more of the length of the vessel over the weather deck.

Explicit requirements exist for drainage requirements on ships with well decks.

On many vessels the cargo hatches and cargo handling booms and winches were located on the well decks between a central superstructure and raised forecastle and poop.

The U.S. Navy cruiser USS Indianapolis (CA-35) being overhauled in April 1942. Closeup view of her well deck area, from the port side, at the Mare Island Navy Yard, 19 April 1942, following overhaul. Note her forward smokestack, catapults, and Curtiss SOC Seagull aircraft.

Naval vessels into the World War II era often had well decks between stacks with the space sometimes reserved for aircraft and catapults as seen in the photograph of the USS Indianapolis (CA-35) well deck (note ladders down into the well deck from surrounding decks).

In commercial ship design categories the "well deck ship" type the profile of the main deck line is broken rather than being flush or unbroken from bow to stern. The earliest cargo steaers were flush deck with openings below rimmed only with low casings. Later designs eliminated this design as dangerous with bulwarks and eventual evolution into the "three island" design with raised forecastle, central bridge and poop superstructures and well decks between.

The well decks of passenger liners were often for the lowest class passenger's use with the well deck of the Titanic reserved for third class passengers. By mid 20th Century the concept of well deck design in passenger liners was "old fashioned" and newer ships were designed with flush decks.

Modern military

Main article: Well dock

A landing craft approaches the well deck of TCD Ouragan

In modern amphibious warfare usage, a well deck or well dock, officially termed a wet well in U.S. Navy instructions, is a hangar-like deck located at the waterline in the stern of some amphibious warfare ships. By taking on water the ship can lower its stern, flooding the well deck and allowing boats, amphibious vehicles and landing craft to dock within the ship.

External links

• this Photo #: NH 104810 USS Suwanee (ID # 1320) "Troops standing in the ship's forward well deck area"
• Wyoming Class (BB-32 and BB-33), 1910 Building Program (showing "A flush-deck hull, raking in an essentially straight line from a high bow to a rather lower stern . . .")
• Manasquan (AG-36) Class: Photographs (showing well deck ship design, search "well deck" in page)