Rapid replacement control fin for an underwater vehicle

A replacement fin system comprising:

• an underwater vehicle with an outside surface;
• a shaft extending outward from the outside surface of the underwater vehicle, the shaft having a shaft body with a body diameter and defining at least one circumferential groove with a groove diameter that is smaller than the body diameter;
• a fin defining a socket with a bore extending into the fin, the bore having a first diameter sized to receive the shaft, the socket also having an internal spring recess of a second diameter greater than the first diameter;
• a canted coil spring in the spring recess, wherein coils of the canted coil spring have a non-circular coil shape, and wherein the canted coil spring can occupy a first canted position in which the coils are canted generally into the bore and a second canted position in which the coils are canted generally out of the bore;
• and
• a spacer configured for removable attachment to the shaft at a location between the outside surface of the underwater vehicle and the fin body.

A replacement fin system comprising:

• an underwater vehicle defining a socket, the socket including a bore of a first diameter and an internal circumferential recess of a second diameter greater than the first diameter;
• a canted coil spring in the internal circumferential recess, wherein coils of the canted coil spring have a non-circular coil shape, and wherein the canted coil spring can occupy a first canted position in which the coils are canted generally into the socket and a second canted position in which the coils are canted generally out of the socket;
• a control fin having a shaft extending out from a base of the control fin, the shaft having a shaft body with a body diameter and defining at least one circumferential groove with a groove diameter that is smaller than the body diameter;
• and
• a spacer configured for removable attachment to the shaft.