the "whiskers" in question, as I understand it, are actually hooks to assist in retrieving the torpedo. The propellor normally would help arm the torpedo but this torpedo is a practice round. It has air tanks in the front. At end of run the arming propellor causes the tanks to release air into the forward end of the torpedo to help raise the head out of water and sink the tail. The light blinks I think, or maybe stays steady, and the recovery ship/boat hauls it aboard and readys it for reload and reuse. Its been a while since I worked on it but I think this is basically it.

Keith