“TRIM CONTROL”

By Donald Blount & Dudley Dawson

Professional Boatbuilder Magazine, Feb. 2002

Our Thoughts on this Paper

A planing vessel is a high-performance vehicle.  A high-performance vehicle is a vehicle where dynamic forces acting on the vehicle exceed the static forces.  For planing hulls, dynamic lift from pressure on the hull bottom provide more vertical force than the buoyant force of water.  On airplanes, the aerodynamic lift force exceeds the force due to gravity.  On F1 race cars, rumor has it that the down force of the foils exceeds the force of gravity at high speeds, which would enable the car to drive upside down on the roof of a tunnel – totally high performance.  So, it is important to keep in mind for all these types of craft, that the angle of attack is important, in that it drives the balance of forces, of which drag is one of them.