I recently bought a Voyager Pontoon boat with a strange prop lock on it (1999, 135HP Mercury O/B.) It is a "Stern Safe, Prop Lock" with a code of "A0" printed on it. It appears to be a flat washer type of nut with three little holes in it, sort of like a spanner deal. A search of the internet does not show reference to this company or lock. Does anyone know where I can find a wrench for this lock? Thanks.