An improved stern design for many types of small watercraft to eliminate “tail dragging”, porpoising, oversteer and “slide out”, improve longitudinal tracking, and provide faster planing at lower speeds. This hull extension, consisting of two buoyant sponsons extending astern of the motor output, supports the weight of the entire motor propulsion unit, extends the planing surface, shifts the center of buoyancy rearward, resulting in an ability to maintain an even fore-aft keel in a very lightweight hull. Under acceleration and cruising, high pressure under the extensions along with an improved center of gravity keeps the boat from tail dragging. Interior chines formed as part of the inner lower surface of the sponsons provide straight tracking under power, even without other hydrodynamic aids, and provide resistance to oversteer or “slideout” in turns. The long sponson extensions protect an outdrive system from contact at the stern or sides of the boat.