Heavier boats used for pleasure, fishing or commercial applications often sit high on the water and are hydro-dynamically different from other lighter boats. To address those differences and in response to additional challenges, Mercury developed its Command Thrust family of outboards.
The larger CT gearcase creates a bigger footprint in the water, providing more leverage to better control your boat. The larger torpedo, combined with a bigger-diameter prop, can lift a heavy boat onto plane more easily and hold it there at lower speeds without impacting top speed.