Trimaran sailors..........

[earthbm]

A bit confused here. Are people talking about mini-keels on the main hull? On a trimaran?

If keel = weighted bulb, how does it contribute to the righting moment, given the small heel angles?






Dragonfly 35 Tri

[w32honu]

Originally Posted by earthbm

A bit confused here. Are people talking about mini-keels on the main hull? On a trimaran?

If keel = weighted bulb, how does it contribute to the righting moment, given the small heel angles?






Dragonfly 35 Tri

Yes this would be an LAR (Low Aspect Ratio) mini keel with some sort of NACA shape. Low aspect in terms of depth to chord. So the keel would be only 12 to 18 inches deep generally. Mounted on the main hull only.......although some designs have mini keels on the Amas much like a catamaran. The total draft with keel might average 3' 6" to 4' 0".

But there is no ballast or lead weight. It is strictly for resistance of leeway and not for stability or righting moment. That is provided by the buoyancy of the Ama. In fact some mini keel designs add slightly to buoyancy.............just the opposite of a ballasted keel.

[earthbm]

Oh, so basically a reinforced fixed daggerboard? Gotcha. Not having turbulence in the slot behind a centerboard may compensate for the shorter aspect I suppose.

As far as claims about pointing pointing I suspect most would just look at AWA, because recording leeway is too much work.


Dragonfly 35 Tri

[Fast Scarab]

Originally Posted by Factor

An endorsement of Fast Scarab's designs, I had a 9 metre tri of his and it was a great boat.

Thanks Factor, hope to see you out on the water in a year or so.
Ray