What type and size is the woodrif key on a 1985 H-31 powered by Yanmar 2GH20? The long story: Backed out of my slip under power. Put transmission into foward and nothing happened. Popped the roller furling gennie for control. Sailed out of danger, turned around, and returned to my slip under sail. Investigation showed that the shaft had slipped toward the stern and the woodrif key was missing. Found metal filings from the set screws gouging the shaft. Funny that I can't find the woodrif key in the engine compartment.