Hi
I have just acquired a 2011 7.5 Koncept to compliment my 5.8 and 6.6.
Yesterday i struggled to tune it to 0 - 20 knt very flat conditions, used on isonic 115.
Using the 75% 460 KA mast, i had it set to 20mm less than printed spec in both out and down haul so visually it looked right on the beach.
Loose leach to 3rd batten, full lower profile touching boom to almost harness lines when sailing.
However, it was so twitchy (was gusty) and it would not really power up much in gusts. I could feel it just felt dead.
Anyway, i kept letting downhaul off in 5 - 10 mm increments, ended up with loose leach to 2nd batten. Slight improvement, but still didn't power up like my smaller Koncepts when a gust hits.
Also reduced and increased outhaul but no joy.
Compared to a mates 2009 Koncept 7.5, it looked vastly different, less loose leach, less outhaul, but less power.
Any suggestions as i just tried everything i could think of.
cheers

I've found my koncepts to be quite sensitive to boom height. If it ever slips I know right away as the sail feels dead and horrible. Something else to try but doesn't explain the twitchiness.