What is you weight?
I'm a bit puzzled trying to balance the numbers you've provided us here?
First, where are you placing your mast foot with your 6.0 m2 and 7.0 m2 rigs?
Mondy hit on this, and it could be critical.
What other fins (besides the stock 48 cm Drake) do you have?
At what windspeed do you rig down from your 7.0 m2 to your 6.0 m2?
Are you tuning each sail quite a bit as the wind comes up....i.e. adding more downhaul and adjusting the outhaul on the 7.0 m2 rig as it gets hard to handle and then rigging down to the 6.0 m2 and beginning to tune it with downhaul and outhaul?
Here's what I see:
In 15-18 knots, if you are 90 kg. (198 lbs.) or greater, then you might get away with continuing to sail your 7.0 m2, but you would normally be faster and more comfortable on a 5.5-6.0 m2 rig at about 18 knots..
At a full 20 knots (and up to 22 knots) again, you could sail a 6.0m2, but a 5.0-5.5 m2 would be easier.
So, you can see my dilemma here.
Give me a little more information and maybe I can see where to suggest to you to get a better balance on your Carve 131, but as you suggest, at 18 knots, the Carve 131 is at the very top end of it's range, and you want to sail it up into the low 20's.
As far as the "rounding up" and heading upwind until you stall, that's pretty normal for someone sailing at the very top end of the range of their board and overpowered on the rig.
Why do you keep heading upwind.....?
Mostly it's a "self preservation" issue.
If you do the things necessary to stay on a beam reach (or any steady course that's not right about as high upwind as you can go) the rig continues to load up, the pressure on you (the sailor) increases, and at some point you are sure you will simply "explode:.
But, if you have your harness lines adjusted correctly, you can "ease off" slightly on your sheeting angle (no change in rake of the rig, just a slight "easing" of the sheeting angle to reduce the pressure) and stay on course.
Moving your harness lines back (as Mondy suggests) could be a solution, or it could make your situation worse. It depends on how you have your lines adjusted currently.
Your "analysis" of why you keep tending to go upwind is probably fairly accurate, and as Mondy suggests, part of the solution may be to do the things that increase mast foot pressure (to drive the nose off the wind a bit more) but I get the distinct impression that you are using "heading upwind" as a bit of a "safey valve".
When you get everything balanced, you won't need the "safety valve" as much, and you will be alot more likely to lift your heels, put all your weight on the harness (commitment here), and apply the proper pressure to keep your board heading across the wind, at seemingly ridiculously fast speeds, with complete control, because everything balances.
Hope this helps,
Last edited by Roger; 27th February 2008 at 08:42 AM.