Hi Shawn
Your V squared equation is correct. But look at it this way, it means you can space
your huge sails out over a much greater span. For example, you could go 9.0, 7.5,
6.5. That said, a huge rig is going to cost, and you can either pay the cost, or
not plane, you get to choose. With a 9.0 you'll want a huge carbon boom, which
will be about $500, and a 100% carbon SDM 520 mast which will retail for about $500
(but I've got a brand new one I'll sell for a lot less than that, as my unusually stubby 9.0 rigs on a 490). You're going to need a fairly
wide board (say about 80 cm minimum), with a huge fin also, to make that work.
The nice thing about huge gear is that it's mostly a racerhead thing and they turn
their gear over every year, at a typical 50% reduction, so used gear can be a real bargain in a low wind quiver.
My 9.0 gets my 180 lbs planing in about 10MPH. The real experts on this are Carl Christensen, and
Sarah Ranes, maybe one of them will chime in here. Due to friction (sailors call it drag),
a bigger sail than 9M is not going to get you planing earlier than a 9, The lower limit in wind
speed is about 8MPH as a planing threshold (for a light guy who knows how to pump).
BTW, I'm currently dropping from my 9.0 to my 6.5, it's doable, but just barely.
-Craig
Shawn Henderson wrote:I don’t speak math real good, so this may be off base or missing something, So I need to ask...
"Force on a sail is proportional to the square of the wind velocity" I found that one on the internet so it must be accurate.
So if I understand correctly what that means is if the wind halves from 20 to 10, the force on a sail will Decrease by four times (25% force is all you get)
This curve makes me think you get diminishing returns on your sail size to wind speed.
At some point a larger sail would become more cumbersome to use while offering diminishing benefits. A lower top speed = less fun in the best case, with the potential of not getting to plane any more then before spending big $ on a new sail, boom and mast. (Unless I also buy a special formula board
.)
Assuming I am at least partially correct. It would be better to sit it out and concede a skunk at some point, but at what sail size? I need to find the top of my quiver without wasting money I could spend on a board, or update to my existing sails. Any help? I am gun shy on this purchase. 7.5 is my biggest sail and it has not been quite enough to plane at times. Thanks, Shawn