marlinspike

thumb|right|A typical marlinspike with lanyard thumb|A large marlinspike being used to splice a wire cable A marlinspike (, sometimes spelled marlin spike, marlinespike, or [archaic] marlingspike) is a tool used in marine ropework. Shaped in the form of a narrow metal cone tapered to a rounded or flattened point, it is used in tasks such as unlaying rope for splicing, untying knots, drawing tight using a marlinspike hitch, and as a toggle joining ropes under tension in a belaying pin splice.

Marlinspikes are usually about long but may reach or more when used for working heavy cables and ropes. They are usually made from iron or steel, whereas fids, similar in shape and function, are formed from wood or bone. Historically a separate tool, the marlinspike is integrated in specialized versions of folding rigging knives and pocket knives.