My boat cover is a one piece and it was custom made to fit with the motor in the up position. If I lower the motor to keep water out of the prop area the cover will not fit properly.
I took an old rainsuit, the bibs, and slipped it over the prop down to the crotch in the suit. Then I took the legs and wraped them backwards and tied them in a knot around the lower unit.
So far it is working good.