Gerard DeRoy: Hull inside

An interesting hullform. Can you explain your reasoning behind the way the 'keel' is higher than the turn of the bilge?

Hi Will,
Was wondering if anybody would notice it. Reasonning: Advantages: Form stability(low water ballast far outside) , lower draught. Potential disadvantage:Water flow separation(going from one hull to two). There is a flat bottom keel (20 feet long,
3 feet wide going from 6 to 28 inches height in the back) which will separate the flow anyway. Experimental motorsailor. very light, water ballasted + lead sheeting under the flat keel , junk rig, leeboards, L/B = 4.5. Design has not been exposed to professional designer yet, which I am not.
Thanks for the interest,
Gerard

ok - but why not just have a flat bottom? I guess the curved surface is going to be a little stronger, but I don't recall seeing anything in Elements of Boat strength about the Lord process not being strong enough to incorporate flat panels

Flat bottom? Agree that Lord process would be strong enough and this had no influence on my choice. I thought I was losing around 4 inches on draught and also on vertical position of water ballast. For construction : It is my first boat construction and I felt ill at ease with the required joints of a hard bilge design. For the design I felt that a hard bilge would be more difficult because of these developpable surfaces requirement. Stability at anchor? I have not done study on the subject but hope that those shoulders( on a light boat) will help to stop the rolling a bit.
Gerard