Amazing! Never heard about all this before, thanks Floyd!
At least in something my Serenity is surely better, less problems of rolling on it than you told about Div 2. But very interesting the Div 2 construction, now I'll look around if someone has a board like this in his cellar or garage...
I've found that in some way posters have given a judgement about gliding and planing of Div 1 and Div 2, so a vote I think would be simply like a final summary of a test, like you can see on windsurf magazines; and the same could be for f.e Kona, Phantom 380 and 320, Ahd Tactik, Mistral One Design, and many other (long)boards.
Anyhow for my bad purposes (this is what I call thinking at buying my 9th board): I have a lightweight custom flapper board (nomex core) that is about 263x73 about 150 litres, pheraphs 8 kg, was the the narrow version of the classic 1 mt wide made by this local shaper (Trevisiol); straps on the edge of the board, sharp rails, lowest scoop (sticks even on small waves...), flat hull. But obviously planes easy with HSM Stealth 9,5 and also HSM Superfreak 8,0. Obviously doesn't glide so well in underplaning situations, especially upwind being without centerboard. Here it is:
I've see this Mistral New Ventura from 2009, 343 x 72, 255 litres, centreboard and adjustable mastrack, triconcave to v in the tail, sandwich intec but obviously not carbon, nomex or other pricy materials. Straps in various positions, but more inside the board. It vould be surely glide upwind far better than my flapper, weight not declared but I suppose around 13-14 kg (seeing the volume, similar to my Serenity of 257 lt).
Herer a drawing:
So, as with 9,5 I can plane with about 10 knots or less, what would be the planing threshold for me (90 kg) with the same camless 9,5? A bit or much higher? And gliding compared to Serenity?