Hi Patrick,
welcome to our international club!
We're really happy to notice that 152VO now starts to spread over France and more and more french members join us (like the Netherlands, Belgium and Switzerland already did before).
The Jupiter is a phantastic design and a really fast boat. Regarding the turnfin: 1 mm aluminium should be strong enough as long as you don't crash the boat.
By the way: we'd be more than happy to meet you and some more of our new french colleagues on the
3rd International 152VO Competition which takes place on 07. - 10. August on Lake Bigge (Northrine Westfalia), about 500 kilometers from Paris. It's just phantastic to see some dozends of these boats racing together - it is like a big international family of vintage outboard racers. We'll be there the whole week long... maybe you'd like to join us for a real racing holiday?!
Have a lot of fun in our racing class and on our forum. Don't hesitate to ask any question!