A trim tab of resilient material affixed in a cantilever fashion at the stem of a boat and of a regressive flexural stiffness such that when deflected, the undersurface of the trim tab assumes the shape of a progressive curve in the direction of water flow. A trim tab of a progressive curve which has gas or liquid ejection to the undersurface to control the boundary layer. A trim tab located under a surface drive whereby the bite of the propeller is controlled relative to the trim tab and the trim tab is controlled to optimize the boat hull.
CROSS-REFERENCE TO RELATED APPLICATION(S)
The present application is based on U.S. Provisional Patent Application entitled "Boat Trim Tabs and Surface Piercing Propeller Drive", Ser. No. 60/293,618 filed May 25, 2001, which is hereby incorporated by reference in its entirety.
A trim tab shape control system for a boat with a transom according to an embodiment of the present invention includes a flexible plate and a trim tab control system. The flexible plate has a forward end attached to the transom, a rearward end, and an operative bottom surface. The trim tab control system includes a first force mechanism that is attached near the rearward end of the flexible plate and at least one second force mechanism interfacing the flexible plate between the transom and the first force mechanism. The force mechanisms are operative to deflect the operative bottom surface of the flexible plate in a controlled curve while in an up position, where the plate retains a shape in a down position which varies with force applied by the first and second force mechanisms and the operating conditions of the boat.
A boat control system includes trim tabs mounted on the lower transom of a boat, with an electric trolling motor attached to each tab. The control system controls positioning of the trim tabs within a trim range and within a troll range. If a main engine ignition switch changes from off to on while the trim tabs are within the troll range, the control system automatically moves trim tabs positions out of the troll range, and disables the trolling motors.
