Marlin spike pocket knives feature a sheepsfoot blade on one end and a marlin spike on the other end. A marlin spike is shaped in the form of a metal cone and used for unlaying rope for splicing, untying knots, and more. Most marlin spike pocket knives are also equipped with a shackle opener used to open and tighten screw-pin shackles used on marine rigging. Check out our great prices on marlin spike pocket knives below.