Q: moving fins towards the tips of the board? Effects?

[markusf]

Hi

I'm building a twintip board, but the board I'm copying has fins quite far away from the ends of the board. For example loose's TX141 http://www.loose.it/tx_line.htm has fins really far from the tips.
But as I see it this is quite a exception as most boards have fins quite close to the tips.

So the question is what kind of effects the fin placing will have and is there a rule of thumb for balanced placing?

Cheers
markusf

[Dwight]

My Amundson board had multiple fin holes to allow me to move them closer to the end. I rode the board with fins closer at one end versus the other. I found the board held better at the end with the fins closest to the end. I now ride everything with fins flush with the tail.

[Hernan]

Fins placed farther aft gives better directional stability (tracking), making the board less turny. It could be said that aft is also faster. In a Twinntip you have a extreme kick in the tail in relation with fin size, so general board design issues doesn't apply exactly. In a sailboard a fin placed closer to the tail feels smaller, with less lateral resistance.
Front Fins are less catchy placed farther aft, as they are a bit more off the water.
Other variable is that a fin placed close to the tail makes the nose ride lower.

The best tip: They have to look as the are in the right place.