Fin Box

I don't know what would have caused it - you'd think the fin must have had some wobble and the bolt flogged the hole out - but a tuttle or powerbox can't wobble as they are tapered and wedge in tight. Weird.

But it would be an easy fix.

You need to fill the hole with a bolt in place, but without letting everything get glued together with resin, so use a mould release wax. To save having to buy special stuff, Kiwi shoe polish works great (clear is best to on save mess).

Rub shoe polish all thru the inside of fin box, particularly on the upper surface (the bit of box closest to the deck)
Cover the fin base well with a thin layer of polish, let it dry for 10mins, and insert in board.

Insert the screw in the good hole.

Now for the stuffed hole, get a bolt way too long - like 20-25cm long and cover all of it with polish too. Fill the threads with it well - chockers with polish. Now screw that into the buggered hole so it goes into the fin well but you have say 5-10cm of bolt sitting above the deck.

Now fill hole with resin up to the level of where the bolt head normally sits. Even better, resin mixed with aluminium dust if you can find a casting shop to sell you just a little bit. Dribbling it down a drinking straw will help get it into the bolt hole without getting too much in the big hole in the deck
Then clean up excess dribbles with cotton buds

Once the leftover resin in your pot has started to gel and you can only just put a dent in it with a nail etc, just to be safe, give the bolt a half turn outwards just be be 100% sure the resin will not stick to it.
24 hrs later reove bolt.

You now have a fixed hole. Trouble is it will be damn tight so to make fin installation easier, get a drill bit 1mm bigger than the standard bolt and bore out your resin. Best to wait a few days for that to let the resin cure 100%

Would it be worthwhile putting in a metal sleeve?

what you have done is at some stage hit a rock or something and pulled the scew through the box , have a look at the back of the box and see if the fin hasn't damaged the box , if you have an old carbon batten about 10mm just glue it in, if you haven't got that get some plastic tubing about the same diameter as your harness lines
"edit" is the hole the same diameter inside the box as the top

I think this is the variation in tuttle fins that causes the holes to elongate. Just a thought anyway.

Is it only the hole where it meets the deck that is oversize (i.e. is there a 'tube' that's also been worn)? I have a formula board where this is the case, but its a deep tuttle and there is very little between the top of the finbox cavity and the top of the deck where the screw sits.

I really wouldn't worry about it all, other than using a bigger metal washer on the screw to spread the load a bit and a rubber washer underneath to even it out.

Too many jumps old salty you need to take it easy dude, i seen ya trying those forwards

I bought a 2nd-hand Vector tuttle-box fin that did this. Didn't realise it at first, but the screw threads go directly into the body of the fin material. On all other tuttles I've had, they appear to have a sleeve of some sort - there are bolts that run through the box.

After half a dozen uses, the thread stripped. But I know why - the hole that stripped was slightly off the hole in the board so the screw was going in at an angle.

Any suggestions for fixing the position of the hole in fin?!