Hello Folks

I'd like to build a new fixed seat boat, and am currently comparing designs. I've entered a few into my Hullform program to see if there are any common parameters that make a fast boat. I know from yacht design work that I have done that these parameters are (for yachts anyway) wetted surface, prismatic co-efficient (PC) and longitudinal centre of bouyancy (LCB.

None of the boats I have access to lines plans or offsets for show any real correlation to the results I would have expected, which I thought would be for a 220 Kg (480lbs)boat of 5.0 m waterline (16'4"), wetted surface 2.7 M2 (29 sqft), PC of about 0.56 to 0.60, LCB at 54% aft of the LWL,

Has anyone got some ideas for me of what the optimum values for these parameter are considered to be, or some actual values from "fast boats"?.

Many Thanks - Foster Southland New Zealand

-- Foster Price (f.price@xtra.co.nz), August 07, 2004

Answers

Dear Foster,

My advice to you is to stop thinking in terms of formulae and start looking at the actual boats that have proven to be successful. Designing open water rowing craft is not like designing power boats with engines of known, steady and predictable power. Comfort is another factor that should be considered. A boat which makes the oarsman feel secure will be more efficient because it causes him less stress. You're in the ballpark on the length factor, but hundreds of pounds off on weight. I should add that there is no optimum boat for all people, in all conditions, under all loads. An experienced human being is much better at designing human-powered boats than a computer. Good luck.

Yours,

Andre

-- Andre de Bardelaben (middlepath@aol.com), August 09, 2004.