30 September 2010

How Slow is Fast?

2.2 knots, 2.3, 2.1, this is boring. Maybe I'll just unroll the gennaker, screacher, reacher (what the heck's the right name for this sail anyway?) and scoot off towards the Benicia Bridge. 3.7, 3.8, 3.9, ah that's better. Hmmm, I wonder how high I can go with this thing? Up, up, sheet in a bit more, up, up, up. 3.2, 3.3, 3.1, not bad.

On a light air day, a 50% increase in speed sure feels good, but is it? It appeared that I was making better progress up river, and I was certainly sailing "to windward" albeit with some pretty fat tacking angles. I swapped back and forth a few times, low and fast, high and slow. Subsequent informal analysis of the GPS tracks revealed anywhere from a 10 to 25 degree disadvantage in sailing angles with the big sail set, most often at the wide end of that range. Plots suggest that if I can keep it in the 10 to 15 degree range this just might be the fast way upwind in super light air. Of course, I'll need some better data collection to confirm this. I'll have to see if I can get my GPS to project a waypoint way upwind and then monitor VMG. Gennaker, screacher, reacher? Hmmm, maybe it's a "code zero". Sailors and their terminology . . .

1 comment:

Dean Fulton said...

What's mister "I-invented-the-Weta" have to say about your angles? Maybe you 3-hullers would be better off sailing w/ a wind-minimum rule like those whiney America's Cup rich guys.
Dean