# Tri plane

Can someone please explain this bottom contour and what its performance characteristic are?

I’d also like to know,Whats the difference between a double concave and a tri-plane hull?

Thanks,

HAU

First of all, you can shape a tri plane any way you want, as long as you have 3 planing surfaces somewhere on the bottom of the board.

Tri = 3.

Dbl=2.

You can shape tri any way, including making it ride like a double concave, so we need to see exactly WHICH tripanel to be used as an example.

Of course, you can shape a double concave any way you want, as long as it’s got 2 planing surfaces in the bottom …usually from the WPoint back.

Traditionally, a tri-plane is a bottom contour consisting of 3 equal panels. Imagine dividing the bottom in to three equal parts lengthwise. The middle panel is usually flat and the two side panels are “V”… basically a panel “V” bottom with a flat spot down the center. Variations could include concaves, etc… what LeeDD was saying. -Carl

I’ve seen the Merrick TPH from the 80’s, and it consists of two concaves, separated by a planing surface down the stringer, and with one down each rail. The flats are maybe, I dunno, 2" wide or so, give or take. The performance charatcteristics are that you surf like Tommy Curren.

If you surf like Tom Curren why doesn’t everybody use them?

i fort ‘yoomer’ was banned from swaylocks ???

like lee said-tri means three planing surfaces.it could refer to a concave type bottom you are talking about, a hull bottom and even when foiling the leading edge of a fin it is done via tri-plane cuts…

A “triplane hull” was what I remember seeing the Channel Island ads in the 1970s showing …hasn’t Al Merrick re-released this design in his recent thruster bottoms , from memory ?

ben

it seems like i heard or read about him doing so, but can’t say for sure.that design concept came from cundith/greenough at wilderness.i believe duncan still uses that bottom…

The C.I. version I remember had dual concaves through the center with beveled panels closer to the rail. I always thought of it as more of a quad hull but I guess Al Merrick can call it whatever he wants.