Swinging Keel Strut:

Developed for use on a proposed prototype for a new Olympic Class racing keelboat, this swinging keel strut was designed to support a 450 lb. keel with a highly stressed bending load induced by the process of winching the keel to windward on upwind legs, so as to give the boat more resistance to healing, and thus allowing greater thrust from the sailplan and higher speeds upwind. The spud at one end with the 2 holes fits into the streamlined lead keel. The integrally machined keel strut pivots are visible about 2/3 of the way up the strut, and the clevis fork at the far end accepts the hardware used to swing the assembly. The strut is about 6 feet tip to tip. The last 2 pictures show the 6061-T6 plate stock fixtured to the vertical machining center with the strut in-process. The hydrodynamic surface up to the pivots is a NACA low drag airfoil section with a tapered planform and variable thickness distribution, which was hand finished to better than a 32 mico inch finish.