Originally Posted by Birdface
(25 foot 1976 O'day, 15hp Evenrude o/b, 7knot hull speed)
Your hull speed is only a bit over 6 and that O/B certainly isn't going to make you surf over that. That number really isn't that important .... unless... you are making judgements on how far you will get in X hours. That's when you can get yourself in trouble. I would use 5 or maybe even only 4 kts. in any time/distance calculations for your trip.
That's one of my reasons for going motorsailer as my hull speed is only 7.1 ..... but I can hold that all day almost no matter what, and being way over-powered I can even break the rules and hit 8 if I want to Waste a lot of fuel. I usually figure my speed at 5 or 6 when planning trips point A to point B.