Details Captain Fin – CF Keel The CF Keel is the perfect addition to Captain Fin’s extensive collection of twin fin shapes. This template is a traditional keel blended with a modern keel fin design. The wide base and a large surface area allows the CF keel to generate speed while the more upright profile will allow you to lay down those buttery turns. This will work great in classic shapes as well as more modern fish outlines. Fin Specification Size Area 25.99 Height 5.35 Base 6.2 Foil Flat Construction Fiberglass