Re: considering a contessa 26
What speeds did you get with your Yanmar after re-propping?
I''ve also got a yanmar 1GM10 on my contessa and have been disappointed to max out at less than 5 knots. Often with a current or headwind and some growth late season I'm seeing only 3 knots at cruising RPMs (3000). I've currently got a 2 blade that I have slated to be removed and re-pitched - the engine is definitely getting up to speed so I think there is room to pitch the prop a little more aggressively. But your post piques my interest.
I debated going to a 3-blade but because of cost, and because the 2-blade doesn't spin (it hides behind the keel) I decided to keep it.