M_Boats: Older M17 rudder measurements needed

I have the original rudder from a mid-70s M17 I used to own. It's the fixed rudder where the blade undershoots the keel. Just for the hell of it I'm refurbishing it and re-installing the pintals so they will line up correctly with the gudgeons on the transom of my early 90s M17. I have both the stock and IdaSailor rudders and know the downside of a fixed rudder, but one can't have too many rudders, can one? I'm interested to know how much gap there is between the top of the rudder's undershot blade and the keel. Anybody know that measurement off hand? Thanks. Tom Smith t _/\_