What effect does trim have on boat performance?
The trim angle of the outboard/stern drive has a distinct effect on the planing angle of the boat, which, in turn, significantly alters top speed and handling. The engine/drive should be trimmed in for best start-up acceleration and shortest time to plane. The engine/drive would then be trimmed out for peak performance. If trimmed “in” (under) too far, the bow drops and the boat runs too wet. In this condition, top speed drops, fuel economy decreases, the boat may oversteer in one direction or the other (“bow steering”), and steering torque will increase (to the right with a right-hand rotation propeller). Occasionally, extreme trim under can cause a boat to list to the left (with a right-hand propeller).
