I learned to windsurf on a pond near the local uni, where I was doing my studies.
It was all 1-design racing, I was told from the late 70s to 1982.
Nice club, we'd all practice together and go to competitions in faraway places as a group - was fun.
Then much better pointing boards like the Mistral started to show up, then better and more expensive Mistrals -
as you said only dentists and doctors could afford changing planks everytime a new board was coming out.
Even the early Mistral people were complaining about the newer Mistral guys - they were "cheats".
Then D2's - Crit was the first one at the lake, etc.
The club could not adapt the rules, they tried to remain a single class,
but within a year the club had fallen apart, and that was the end of it.
I vaguely remember Friday night racing at Botany Bay went the same road, no?
It was the beginning of Tupperware sailing - by then I had a trailer like the others.
Anyways, nice plank Greenlead. I did not remember that Mistral had a twist-in dual-hole uni like that.
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The safety plug/tether is useless as well, it just pulls out too. 
