[Destroyer]

Originally Posted by garbubba

I'm confused why you think the plate in the water would cause the motor to pull on the transom? The motor pushes the boat, more drag at the motor would just mean a little less push, but no more pressure on the transom.

Or am I missing something?

Since there is a pivot point at the engine mount there are different torque forces being applied to the transom. While you are correct that the main propeller force is being applied in a direction that pushes the boat forward through the water, there is a lesser force that is actually either pulling or pushing on the transom. While this force does not diminish the driving force through the water, it does do other things depending on how the engine is trimmed. Thus, if the engine is trimmed high, this force has a tendency to actually pull the bow of the boat up out of the water, and if the engine is trimmed too low, it will cause the bow to dig in too much. The plate in the water at the wrong angle will increase this force since it equals additional friction of the engine moving through the water.