Snip from Keith >Another problem is that is same weather, the prop (and cooling >water intake) will probably be out of the water a fair amount of time due >to >the motion of the boat in the waves. Not good either. Correct Keith the out board even with a long shaft will not be able to pull clear water. The end result is a motor life of hours not years. The hull design of a trawler does not react the same as a sailboat ,V bottom , or cat hull. The prop / shaft even in minimum wave conditions will spend to much time sucking air instead of water. Some of this is simply a reaction to the flat back of most trawlers. The shaft end needs to be bellow the hull past the cavitation plate to work consistently. If you do have a canoe type stern the power head then seems to spend to much time under water on a larger vessel. My experiences Willy Invader #1 39 ' Kishi conversion