the size engine
depends on the keel
type and hull
shape and the purpose of the boat. a sloop
used mainly for racing
and the engine gets it in and out of the harbor--wont neeed much--for a 35ft ericson
mII they used a 20 hp engine...but then, that yanmar
WILL get you into and out of bad stuff in that boat very easily. my formosa
has a perkins
54 hp engine now--it was cruised to here from sf with a 37 hp westerfreke.....the westy actually did a decent job of pushing the boat--but the perkins
will do some better---i prefer 54 hp over 37 with a 41 ft deep keel
cruiser. i would prefer a bit more, but this will do fine.
i cruised for a near year in the gulf was a 37 with a 28hp or thereabouts yanmar--did fine in storms and with head
winds--coulda been a bit goosier but was adequate...