Re: Scalability & Tunnel Sterns
- View SourceCurtis,
Yeah, that "dozen or so prototypes" is a big deal. Tunnel stern boats are particularly hard to model, too. Normally you can build flotational models and tow them in a test tank to figure out hull resistance and some other things. Weston Farmer has a wonderful chapter on this in his book. But a tunnel stern is different. The tunnel doesn't fill when you tow it. The propulsion MUST come from a pump in the tunnel to test the hull's dynamics. This would mean installing scale engines, radio control, and whatever measuring instruments are needed. Fascinating, to be sure, but the cost of modeling goes way up. But given the cost of constructing a full-sized boat and powering it, this may well be justified. Particularly since the guys who really understood this hull type have left this world.
Robb was going to build the 12' boat by eye and hope for the best, since he "got lucky" (his words) with Rescue Minor. By the way, I think you're right that he intended 4-5 hp. After I sent the last message I realized that the 7 hp figure was the most he'd put on the Sport Boat. Memory is the first to go, I guess.
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