page_title: Cofferdam
section_title: Naval architecture
hierarchical_section_title: Cofferdam / Naval architecture
caption_attribution_description: English: Inside of cofferdam (small tank on ship). Smaller pipe is for installing echosounder, big pipe is for emptying of cofferdam. Polski: Wnetrze koferdamu na statku. Ciensza rura doprowadza przewody do przetwornika echosondy, grubsza sluzy do oprozniania koferdamu. Deutsch: Als Kofferdamm wird im Schiffbau und im Bordbetrieb eine leere Zelle zwischen zwei voneinander sicher zu trennenden Räumen an Bord von Wasserfahrzeugen aller Art bezeichnet.
context_page_description: A cofferdam, also called a coffer, is an enclosure built within, or in pairs across, a body of water to allow the enclosed area to be pumped out. This pumping creates a dry working environment so that the work can be carried out safely. Enclosed coffers are commonly used for construction or repair of permanent dams, oil platforms, bridge piers, etc., built within or over water.
  These cofferdams are usually welded steel structures, with components consisting of sheet piles, wales, and cross braces. Such structures are usually dismantled after the construction work is completed.
context_section_description: A cofferdam may also refer to an insulating space between two watertight bulkheads or decks within a ship. A cofferdam can be a void (empty) space or a ballast space. Cofferdams are usually employed to ensure that oil or other chemicals do not leak into fresh water tanks which would result in contamination of the drinking water supply on the ship. The cofferdam would be empty at all times and the ship may have sensors within the cofferdam to warn if the cofferdam has begun to fill with liquid.  If two different cargoes that react dangerously with each other are carried on the same vessel, one or more cofferdams are usually required between the cargo spaces.
caption: Inside of a cofferdam on a vessel
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