RE: Formula or isonic 155 for max speed ?
Although I haven't participated in the gps-speedsurfing rankings, I do look at their speeds on occasion.
I carry a gps on all outings, but haven't tried downloading anything on my very old computer at home.
My best speed on Formula is 27.5 knots on my old F147 a year and a half ago. Off shore winds gusting to 26 knots, flat water and an old Gaastra Nitro IV 7.5, Curtis 68 custom fin.
My goal was 30 knots, but I find it very difficult to get close. I hit 24 to 25 knots pretty often, but 26 & 27 are rare. I can't imagine going 30.
I may not be big enough (80kg) to go 30 knots, but it's fun trying.
Good luck to you.
Formula 160; iSonic 111; HiFly Move 105; Tiga 263; '85 Mistral Superlight.
Maui Sails TR 11.0; 9.2; 8.4; 7.6; 6.6; Maui Sails Switch 6.0; 5.2; Maui Sails Global 4.5; 4.0.