Bilge is the lowest section of a ship.It is seen in all dry cargo ships and bulk carriers to drain out holds and spaces when these spaces are hosed down or when water accumulates in the holds especially in case of cargoes of rice etc. which give lot of water. The bilges are also used to empty the spaces in case of hull damage like collision or grounding.

Older ships had side bilges when the tank top did not extend to the ship's side but was tapered off at the sides to form a margin plate. The drain thus formed was the bilge in which the water collected and could be pumped out through the bilge pipeline. This type of bilge system is known as Limber Bilges.

Modern ships however have the tank top extending to the ship's side and the bilge is situated in the aft part of the hold in the form of a well on the port and star board sides. The bilge section is fitted in the well itself with a suitable strainer fitted to eliminate larger debris like dunnage and cargo straps etc. from entering the bilge pumps.

Functions of Bilge

To pump out water accumulated in hold compartments and other similar spaces, like engine room, pump room etc. in case of:

1. Carriages of cargo with high water content like rice which has been freshly harvested. When water tends to accumulate at the bottom of the hold and damage the cargo. Water may also accumulate due to cargo or ship's sweat. Some cargoes like iron swart need to be continuously cooled due to internal heat generate by the cargo itself.
2. Fire in a hold or compartment, when water is used as the extinguishing agent.
3. Bilging after a collision or grounding or in the case of failure of structure.