This album contains photos and a description of the front foil type commonly know and the "Schutt Strut". The purpose of this album is to help anyone trying to duplicate and use the Shutt Strut..
Special thanks go the Sid Shut, a retired aerospace engineer of Southern California, for whom the device was named in the 1960s. Although this type of mechanism was first seen in the early 1900s on a hydrofoil boat built by the Meacham brothers of Chicago, Illinois, it was Sid Shutt who perfected it and recognized it for its dependable flying characteristics.
The purpose of the device is to regulate the flying height of the bow (possibly the stern too, in some designs). The surface follower floats and plans, and when properly working it will always follow the surface.
The Shutt Strut is a one piece combination of a hydrofoil, vertical strut, pivot point, forward reaching follower arm, and a planing surface follower.
When the bow is low, the surfaced follower is high. This results in a high angle of attack for the foil. Therefore the lift is high and the bow rises. This lowers the surface follower (SF) relative to the bow. As the SF lowers, the foils angle of attack (AOA) is decreased until equilibrium is reached. At this point the bow is at the design flying height.
To adjust the Shutt Strut, the designer can change the angle between the strut and the follower arm, the point of rotation (re-drill the pivot hole), change the size and shape of the foil, change the AOA of the foil relative to the other components, change the size, shape, and planing angle of the surface follower, change the length of the surface follower arm (this changes the "gain") change the strut length, etc.
Text and photos by Ray Vellinga, 7/19/2013