Surfing Waves

Ok this ones for the more astute minds in relation to tail design. A friend has a 9'1" longboard. Its a performance board with plenty of rocker, with twin concaves in the rear and a rounded pin tail. Well it had a rounded pin tail. The board has been dropped rather hard on the tail and has mashed a good inch and a half of the length.
My question is what effect will making it into a square tail have on it? I assume it may not turn as well, but is there anything else. Will it effect the way it rides across the face of a wave. Would a different fin set up counter-act the square tail( it has an 8" dorsal and the sidebites out for low drag in smaller waves)?
So is it worth fixing? I myself am not to bad at fibre glassing and could do the job for him. Or will the board be rubbish and tell him time to buy a new one?
Cheers
Craig

Hi Hunsta Happy New year , unhappy ( slightly) for the board.
You will probably be surprised squaring off the broken tail will give you a square pod, probably about about 4" at a guess the corners will act as pivot points in the turn and actually make the board able to turn more acutely! Unless the tail rocker is heavy the nose riding ability will increase as the square tail gives more hold.
Often progressive longboards attempt to mimic short board turnability by increasing the tail rocker, the snap off will have decreased the tail rocker a little.
The position of the centre fin would need to be changed, hopefully the cut off point in the fin box still has enough room to accommodate this!

I would do the repair, see how the board goes ( it won't be rubbish it will be different) then you have the option of buying a new board.
Big plus you will understand a little more about surfboard fluid dynamics

Thanks for that mate. We`ll see what we come up with and try and let you know the results. And a Happy New year to you.
Craig

hunsta,
does your puppy surf?