Matt Broze <marinerkayaks_at_msn.com>: Bradford asked: >> 1. How many horsepower does one dragonboat generate? 2. Do paddlers >> develop asymmetrical/lopsided bodies?<<<<<< > Is it a trick question? The dragonboat doesn't generate any horsepower > at all. It just generates drag when horsepower moves it. > > To answer the question you likely meant based on what I think is the > horsepower that a very strong paddler could generate. The 20 paddlers > times about 1/5 of a horsepower generated by each paddler would generate > about 4 horsepower total. Horsepower = drag in pounds x speed in knots > x 0.003069 (I think). > > I get about 9 knots as their speed. About what a top single Olympic > kayak paddler can do. If HP=speed in knots times drag in pounds times > .003069 then that gives between 3.3 to 4.1 horsepower needed to move the > boat that fast. Matt, I can not evaluate your method, but if 20 paddlers at about 200 lbs each plus boat comes in at about 5000 lbs, my gut feeling, based on some time in small power boats says 4 hp ain't enough, even considering this is at the shaft, not the "rated" hp of the engine. A 10 horse outboard will push a _lightly_ loaded jon boat with two passengers (all up weight about 600-650 lbs) up to about 20 knots. Figuring five hp at the shaft, and figuring the drag goes as the square of the speed, that means you'd need only maybe 1.25 hp at the shaft to hit 10 knots in the jon boat. If the 10 hp motor actually delivers 10 hp at the shaft, then you'd need 2.5 hp to hit 10 knots with the jon boat. In any case, I can't see how 4 hp would be able to generate 10 knots on a boat + passengers displacing some 5000 lbs, although the dragon boats are no doubt fully in displacement mode, are a lot longer than a jon boat (which would be planing at 10-11 knots), and a low-speed propulsion system (e.g., paddle) is a lot more efficient than a high speed screw (e.g., outboard three-bladed propeller running at high revs). -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Sun Sep 30 2007 - 18:33:55 PDT
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