Planing Hull forms

[Paulo.AS]

Hi to all,

I'd like some input on planing hulls form sailboats. As one sees boats like IMOCA 60's flying low on the water the question that begs answering is what's the shape?
Also where to use chines and to what purpose?

Cheers

[ChicagoDrifter]

http://www.******************/Bentley...nced_Hulls.htm

I own the #1 Scheel (lifting keel). Most planning monohulls have some features shown in those pictures. Your subject is to broad to get answers!

[Paulo.AS]

Drifter,

Thanks for you reply & comment. Maybe I was way too broad. So here it goes more refined: As far as monohull sailboats, more specifically sloops, planing hulls follow the same reasoning as for a powerboat concerning sections and buttocks lines? Also can some one point the reason for having chines at the after end of the boat? I've seen some comment that it would increase the ability to carry sail (=power).

Hope this narrows it down

[ChicagoDrifter]

http://en.wikipedia.org/wiki/Chine_(boating)
I don't know what type of chine you are talking about. Please attach a picture. The design of chines is related to stability which has something to do with sail area. Check out some similar threads on the bottom of the page and see if those guys know more of what are you talking about.

[Petros]

planing sail boats are almost always light centerboard boats with flat bottoms with wide beams and usually hard chines. The hard chines allow the water to cleanly shed off the hull. Round bottoms have less drag in displacement mode but tend to "suck" the hull downward as the water moves over the curved surfaces. You can not get a keel boat to plane because it is too heavy. There is a complicated relationship between the amount of lift the hull bottom generates as you pick up speed, the weight of the boat and its CG location, the size of the sails, etc.