The existing headboard/hook, being at that odd angle, digs into the masthead opening and immediately begins to work-harden due to the sharp edge on the stainless steel hole. The photo attached shows the notch after only 1 hour of sailing. After it digs in further, it sort of wedges itself into the hole, and makes it difficult to get out. Maybe after many uses, the whole thing gets distorted enough so that the problem sort-of self-corrects itself. I didn't feel like waiting this long.
My design has a few advantages: The pin (same diameter as original) enters the whole nearly straight, therefore there is more room for error getting it in and out. Once in, all the load is between two relatively flat surfaces, rather than a sharp edge on a cylinder. The load is applied to a large height area of the fitting (and therefore higher area moment of inertia), so that it will not bend or break.
You would be astonished at the ease of hooking and unhooking now (using all the same techniques as before). The hoist height is "essentially" the same. Since I had to use the existing headboard and don't have time before my next race, it's just slightly lower (maybe 5mm). A complete re-design could make it exact. I'll probably do this over the Winter.
Steve |
