Can anyone advise as to where I can obtain a Tuttle fin ferrule. The local shop doesn't keep them.
thanks in advance Nick

Are you referring to cross nuts - those brass cylinders that the screws thread into?
Google "brass cross dowel nuts".

Yep sure am, I could raid another fin but would prefer to buy a couple.

I bought some from this dude

http://www.ebay.com.au/itm/Messing-insert-12-6-mm-windsurfing-fin-/170983667352?pt=UK_Sporting_Goods_Windsurfing_CV&hash=item27cf6bb698

Took about 2 weeks to arrive. You have to buy a few to make the postage worth while, I also added some fin bolts with washers on my delivery.

Thanks mate that's really useful information, I find it amazing that no one has spares here.

usually called a "barrel nut" and I've never found them hard to find

If not at windsurf shops, a specialist fixings retailer will have them (but don't be tempted to go for the zinc plated steel rubbish at hardware stores)

They are also called a dowel fixing nut. The Zinc ones are in Bunnings.
CS