For the two years I had my 1994 P -15 " Just Wight " I used a 62 pound (!)
5 HP Honda 4 stroke. This did just fine in the Delaware River..bucking
currents, getting out of the way of oil tankers and container ships coming
up the channel. I did reinforce in inside of the transom to take the
weight and of course I did not trailer with it hanging on the motor mount.
I could not totally tip the engine out of the water so that when sailing
the lower tip of the prop dragged in the water. Nonetheless...it worked
fine and hull speed was attained at very low rpm. I would think your 3 HP
to be just fine.
Bill Zeitler
ECPA Wilmington, DE
PS: I still use the 5 HP Honda on my highly modified, 1000 pound 21 foot
Bay Hen.