For those who remember, the Tinkler tail was one of those cutting edge shortboard designs back in the day. It involved a flexible tail section, with screws to adjust the tail flex and hence looseness of the board. Mistral even put the concept in to production with the Challenge Flex in the early about 1989. Mistral went one step further and had interchangeable tails for the one board- a slalom and wave board in one. I don't believe they were imported to Australia. The owner of this one couldn't even rustle up 10 quid for this beauty- if only he shipped to Australia!

http://www.ebay.com.au/itm/Windsurfing-Board-Windsurf-board-Mistral-Board-Sailboard-Tiga-/300921466473?_trksid=p2047675.l2557&ssPageName=STRK%3AMEWAX%3AIT&nma=true&si=yxJkcQ2j3dZ%252FOzgdEHiIRHRW2rQ%253D&orig_cvip=true&rt=nc

I'll take a pic of a board Dan Engdahl made that I have , probably the weirdest board i have seen , a hydroplane style thing that has done 40plus knots !
watch this space .

that is amazing!!, what is gained by more looseness in the board?, eg faster, my friend has started to work on a board called the flapper, big square back end, with this rubber flap hanging off the back off the board, im not sure what year its from, or what the flapper does,,,

Interesting stuff, thought about this myself...it is another thing doing it in production..

I remember those Roberts designs. the idea was also used by some on the back of Torquay boards.
the flap helps with cavitation and allows fin to be closer to back and thus less board in water.

yeah, thats right, the fin is heaps far back, and that flapper is supposed to help with spinout, the guy who rides it back home is good, his about 100kg, and uses it as a light to medium winder, im pretty sure he has broken thirty on it, he has sent it off to get a custom made carbon flap, im not sure if that will work or not, im thinking a carbon flap will be a lot stiffer than a rubber flap, which might not work well........or might work better?

I have a Seatrend All Star (haven`t sailed it yet) . carbon board with flapper on the back. very soft rubber. came with a Caveman 50cm fin.

Makes the Tinkler tail look decidedly conservative!

I have a recollection of a conversation with Dan where he said he was going to add another layer of foam to the front half as the step wasn't big enough. To me it looks like that extra layer has the bevels.
He was thinking of counter balance weights to windward and a few other ideas that seemed more "extreme"...