Design and Construction of a Fully Submerged Hydrofoil Drone Boat

Abstract

A remotely operated hydrofoil watercraft was designed and built as a test platform for active electromechanical controls as applied to fully submerged hydrofoils in a form just small and lightweight enough to be tested safely without a human physically at the controls. The goal was to build a watercraft sufficiently large and scalable enough that results obtained from it could be realistically applied to personal hydrofoil vehicles without the danger of a human in the vessel during testing. The project also explores roll dynamics while not on foil.

The vessel was built to a length of 1.53 meters with 0.34-meter masts with servo controlled forward foil and aft flippers. The hull is constructed from lightweight 1/8in plywood with a fiberglass and epoxy composite skin. The foils and masts were 3D printed at low density and skinned with fiberglass. These structures have mechanically performed well, surviving both the hydrodynamic forces and repeated crashes. The foils were designed such that the craft would reach foiling speeds at zero degrees pitch at 4 m/s at a mass of 13.1 kg distributed 70% to the aft foil and 30% to the forward foil. The final weight was 14.1 kg. Working towards digital control, the watercraft is equipped with two ultrasonic sensors for height sensing, with room for expansion, and an inertial measurement unit.