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.

What is the main purpose of a cofferdam?

cofferdam, watertight enclosure from which water is pumped to expose the bed of a body of water in order to permit the construction of a pier or other hydraulic work. Cofferdams are made by driving sheetpiling, usually steel in modern works, into the bed to form a watertight fence.

What is coffer dam what are its application and its types?

Definition  Cofferdams are temporary enclosures to keep out water and soil so as to permit dewatering and construction of the permanent facility (structure) in the dry.  A Coffer Dam is a temporary structure designed to keep water and /or soil out of the excavation in which a bridge pier or other structure is built.