Question: TT Fins: Shapes and Materials

[crazyflyer]

Been looking for info on the web about TTs fins (easy to find advice about size), but what about:

CONSTRUCTION:
-Rigid vs flexible
-G10 vs "plastic"


SHAPE:
-Sharp vs rounded edges.
-Long vs "square" vs "surf"







I begin with:

[Kite2Heaven]

IMO the best TT fins for drive and performance were made by R.F.C rainbow fin company..

[Peter_Frank]

They can write almost "anything" in an ad for a specific fin

But size IS the most important factor, as the hydrodynamic features of fins this size is almost zero.

They are used as directional stabilizers only, and nothing but that.

You can easily ride your board without fins at all - it would perform the very same.

But be a bitch to control usually

A fin with such a low height and wide chord, will never be able to produce much lift, almost zero, because of the extreme vortex so no pressure difference can occur.
Thus "directional stabilizer".

Thin fins will most likely have less drag of course, when going straight, as will sharp ended fins.
But they will also be much more prone to getting cuts when you hit the sand bar or rocks, and way more dangerous for yourself as you can get cut really bad

And thicker more round fins, will most likely have less drag when you slide the board in a tight carve or with pressure on the fin.

But there is IMO no performance issues at all regarding TT fins, it is all about feel and handling, meaning small fins = loose board, and big fins = stiffer board feel in the water.

With directionals it is way more complex, as here the profile, flex, outline means a lot, as the fins are the "power" point and turning point - whereas a TT only uses the fins as stabilizers.

Of course many brands want to make a huge science out of THEIR particular TT fins used, but mostly just PR as I see it

Plastic fins works great, but can break easier of course

Then we are back to size being the most important factor - and changing fin size up or down on your TT will sometimes make the board change dramatically, so worth a go if you havent done that

Peter

[windfreak74]

a good place to learn about hydrodynamics and fins is www.wavegrinder.com
lots of usefull info!

[dyyylan]

in my experience the only thing that makes a significant enough difference to notice is the size. other than that it's just a durability thing, fiberglass seems to chip quite easily and the hard plastic kind (not G10) seems to get brittle and fall apart

length of the fin only really makes a difference as it gets smaller, it can give a little more grip if it's longer (like on the 0.5-inch kind)