Abstract: The invention relates to a pair of five-sided hydrofoils for use in conjunction with the lower unit of a conventional outboard motor. The invention improves the stability of a boat and reduces the time required for a boat to achieve a planar configuration with respect to the surface of a body of water. The hydrofoils include leading edges having upturned angular portions and trailing edges having downturned angular portions. The leading and trailing edges are designed to simultaneously apply a lifting force to the stern and a downward force to the bow of a boat as the boat is propelled through the water. The invention improves the performance, safety, comfort, and useful life of a boat and a conventional outboard motor.