twin keel 2' draft instead of single 7' draft on 65'

[yhxaig]

Any ideas on redisign of a 65' single 7' draft keel ,which is about 12' long.
I intend to build it with twin keels for 2'-3' draft and the keels will be about 40' long.
Similar to the westerly keels but sleeker.Boat matereal aluminium.
How would this effect the rough water performanceor stability?

[Eric Sponberg]

Draft is the single most important factor in keel design. The next most important factors are weight and the location of the center of gravity. You would be trading off all three of these for the bilge keels, so major things are going to happen with performance, generally none of it good. A 2-3' draft seems extremely short, and you might be better off by looking at the 4-6' range. The keels would be shorter in length, obviously, but you would not lose so much of the all important draft or stability. Performance will be modestly different, but not bad, generally. Consult a naval architect to work out the details for you.

Eric

[yhxaig]

I am building this 65' aluminum project and will do several other interesting aluminum projects,power trimaran wave piercing,planing trimaran and several catamaran designs.Intersted in financial backer with $100,000 to do 3 projects.

[Daveynireland]

How about being radical and putting in a lift keel?. Design it right and you shouldn't sacrifice too much on performance. Stand by for imminent details of my next project. check out http://www.northshore.co.uk/index.ph...y46rs/exterior