15 August 2002
Bilge - The curve of a ship's hull joining the side and the bottom.
Captive Crane - A traveling crane limited to use at one facility because of the absence
of track connections to other facilities.
Cavitation - The formation of cavities in a fluid flow due to low pressures attending high
velocities in the fluid.
Chafing Strip - Strips of wood or other material placed on sides of waterfront structures,
fittings, or vessels to protect against chafing from contact with other structures, ropes, or
Cribbing - A framework, usually of timber, designed to distribute concentrated ship loads
and to provide longitudinal stability to the keel blocks.
Elastic Mat - Structural slab on ground (usually of concrete) supporting separated
vertical loads. The elastic deflections of the mat are correlated with resulting
nonuniform soil reaction in computing stresses in the mat and the earth pressures.
Fair-Lead - A fitting through which a line may be lead so as to preserve or change its
direction without inducing excessive friction.
Go-Devil - A tight mooring plug in a pipe, utilized to clear pipe of liquid or debris.
Gypsy Head - A small auxiliary drum at the side or top of a winch.
Keel - The principal bottom structural element of a ship extending along the centerline
for the full length of the ship.
Mortar Intrusion Concrete - Concrete made by injecting cement or sand-cement mortar
into the interstices of previously placed aggregate (it can be placed in the dry or
Skeg - Vertical projection extending below the hull of a vessel to reduce yawing.
Sonar Dome - A bulge or appendage on the keel of a ship, usually forward, for housing
Stoplog - A dam consisting of a piece or pieces in slots in the sides of a waterway to
shut off flow (usually for temporary use).
Trashrack - A grille, usually of vertical metal bars, used to screen out debris from the
entrance to a waterway.