Vintage Prop-Mate Model 116 Propeller Wrench, Cast Stainless Multi-Tool, Patented, American, c. 1978

The Piece

One casting, four jobs. The head carries a deep 1-1/16″ six-point socket — the standard prop-nut size for Mercruiser sterndrives and most large outboards — with walls thick enough to take a cheater bar without complaint. Mid-shank, a square drain-plug opening; at the tail, a curved two-finger hook profiled for pulling cotter pins and straightening the bent legs of a new one; and a raised spine down the face stiffens the whole length. Crisply struck on the shank: PROP-MATE, PAT. NO. 4,089,077, MODEL NO. 116, with the maker's clover device. Dull-bright stainless with honest tool-bag wear and not a crack in it.

History & Provenance

Every prop change on a boat ramp starts with the same problem: a big castle nut, a cotter pin, and whatever wrench happens to be aboard, which is never the right one. The Prop-Mate was the late-seventies answer — a purpose-built, patented single casting that put the socket, the pin puller, and the drain wrench in one tool that lives in the bilge bag and doesn't rust there. The patent dates it: U.S. patents in the 4,089,000 range issued in 1978, which puts this squarely in the era when sterndrive boating went mass-market and the accessories trade grew up around it. Molded nylon versions took over the category later; the all-metal originals like this one are what the nylon was imitating.

Product Details

Why It Belongs in Your Workshop

If there's a boat in your life, this rides in it — one tool that swaps a prop at the ramp, pulls the pin, and opens the drain plug, with no battery and no plastic to strip. If there isn't, it's still a satisfying object: a single patented casting from the era when accessory makers solved a whole problem in one piece of steel. Either way it earns its hook on the pegboard, and at this price it's the cheapest insurance a sterndrive owner will buy this year.