Injam wrote:
So you are saying that the heavier motor would not slip as much as the
lighter one?


No. I'm saying that the greater amount of downward pressure applied
when turning a screw into wood, the more efficiently it drives. Much
different than you boat example.

We're not talking about the "engine" slipping at all. We're talking
about the prop slipping. All props slip. Two props of idential diameter
and pitch will slip the same amount at the same RPM in the same medium.