lapstrake vrs carvel or cold molded

[thomas cashman]

I found an article stating that a lapstrake hull was actually faster than a smooth hull. the reason stated was that bubbles formed at the lap junction and provided more lift (I think). I can understand the if a lapstrake hull is lighter it may be faster and a lapstrake hull will not "hobby horse" in a chop as much. But with equal hull weights if lapstrake were faster why have'nt all the performance boat designers designed lapstrake hull?

[Bruce Hooke]

I rather suspect that the idea that lapstrake hulls are faster is too some degree wishful thinking for just the reason you gave -- if it was really faster to have all those little lips then I'm sure we would see them on the modern go-fast boats! On the other hand, from what I have heard, it seems like at least in casual small boat racing lapstrake boats are able to hold their own with smooth-hulled boats so I wonder if it would be more accurate to say that the lips created by lapstrake planking do not seem to have the negative effect on speed that one might expect at first glance.

[Venchka]

...and they make a pleasant sound too.

Wayne
In the Swamp. :D

[Victor]

There might be something to that. The adhesion of water on a smooth hull can be great enough to ship water inboard. That's what siderails are for. Doesn't it follow that that much adhesion could create drag? A dimpled golf ball will travel twice as far as a smooth one. Aircraft and boat manufacturers have experiemented with dimpling, but I guess the difference is not significant enough to justify the cost.

[JimConlin]

Keep an eye on the Larry Ellison/Dennis Connor set. When they've gone to lapstrake hull surfaces, i'll believe it. Until that time, we'll have to torture other arguments.

[Kermit]

Aw, hell, lapstrake is just faster to build. Looks better too.

[Billy Bones]

Ha! There you go! And don't forget dryer--all those built-in spray rails.

[JimConlin]

As i said, we'll have to torture other arguments.

[Thad Van Gilder]

clinkers much easier for the beginner to get tight planking with, I think...

-Thad

[Charles Burgess]

Originally posted by Victor:
There might be something to that. The adhesion of water on a smooth hull can be great enough to ship water inboard. That's what siderails are for. Doesn't it follow that that much adhesion could create drag? A dimpled golf ball will travel twice as far as a smooth one. Aircraft and boat manufacturers have experiemented with dimpling, but I guess the difference is not significant enough to justify the cost.You are onto something there. A smooth hull drags a layer to water with it...called the boundary layers. Dimples, like with a golf ball, would disturb the boundary layer and allow the hull to break away from it.

Dimpling a golf ball, a baseball bat, a boat hull...all have the same effect.

During one of the Americas Cup, back when the Aussies first hosted the event...one of the American challengers added adheasive vinyl tiles to the hull...the tiles had 1/8 inch grooves in them and served to disturb the boundary layer and enhanced the hull speed of the vessel.