What am I misunderstanding?
How does one get a figure of 6.8 from the two figures 27.5 and 1.3 ?
My ship weighs 23,000 lbf, and I have about 35 hp (Volvo say). What speed should I expect? The ship is a double-ender... a Union 36.... with a big footprint in the water and a wetted length of 33 ft, apparently.