Skeg
Extension of a boat's keel at the back, also a surfboard's fin / From Wikipedia, the free encyclopedia
For other uses, see Skag (disambiguation).
A skeg (or skegg or skag) is a sternward extension of the keel of boats and ships which have a rudder mounted on the centre line.[1] The term also applies to the lowest point on an outboard motor or the outdrive of an inboard/outboard.[upper-alpha 1][upper-alpha 2] In more recent years, the name has been used for a fin on a surfboard which improves directional stability and to a movable fin on a kayak which adjusts the boat's centre of lateral resistance (it moves the center of resistance relative to the center of effort).[2] The term is also often used for the fin on water skis in the U.S. It has been used for the vertical fin on seaplane hulls and floats. The wear-bar on the bottom of snowmobile ski may also be called a skeg.