Asymmetric spinnaker for a West Wight Potter 19.
Designed by Chip Buck, of Point Sails, Spring of 2005
Take a good look at the shape of this sail. The luff is blue, the leech is red, and the foot is white.
Look at the blue luff. Note how full the curved "shoulder" on of the luff is. With a shape like this, the asymm will sail very deep angles downwind, as well as be managable on a reach.
That's my son, Joe, at age 22 months, standing near the head of the sail.
Here's my review of the sail after a couple of test runs:
We've had it out twice on the Oakland Estuary.
The sail is just beautiful. It does exactly what I asked for when I talked to Chip at Point Sails about designing an asymm for the Potter 19.
In particular, I wanted a sail for the P19 that would make the boat faster sailing deep angles downwind. (As we all know, the P19 isn't very fast downwind.... ). Sailing deep and fast was what I asked Chip to concentrate on, and yet the sail had to be able to handle beam reaches without overpowering the boat (for safety's sake)
It's about 174 sf, so it's small enough that the boat isn't over powered and yet it's big enough to get the P19 really moving. (and it's small enough that even a midget like me can handle it easily without needing a sock/snuffer.) And the shape on the luff is full-shouldered enough so that it turbo-charges the boat on a VERY deep reach.
I was very pleasantly surprised to see how well the sail handled a reach as well as a run. It can handle a VERY wide range of sailing angles, and it's not finicky about trim. When you want to sail really deep, it rotates out in front of the bow smoothly as you easy the sheet and the tackline, without collapsing. It's very forgiving (for an asymm). And when you trim in the tackline and sheet, it'll handle angles well above a beam reach.
We've sailed it as deep as 160 degrees to the true wind (estimated), and wind of 2-8 knots with gusts up to 10 or 12 knots true wind (again, estimated).
Redwing was screaming along at speeds ranging from 2.5 kts over 6.2 knots (measured on the knotmeter) on a course of 150 to 160 to the true wind. (that's really deep!) in winds from 2-8 knots. Our boatspeed was so fast compared to the true wind, that at times the apparent wind moved above a beam reach!
(I must confess, at first I thought we were sailing in really "shifty winds" because we kept "seeing" the wind direction "shift" from deep on our aft quarter to above our beam. But after a few runs, I finally figured out what was happening, and started trimming accordingly!)
We've successfully done both inside and outside jibes with the asym. But the inside gybe takes a bit of technique to do successfully.
All in all, it's a winner, IMO. It's a true "modern all-purpose", as nice as the custom-designed one North Sails built for my Catalina 27. It's NOT one of those old fashioned asyms that can either reach or run, but not do both.
We've made some progress on how to rig the P19 for the asymm, but we're still working on the details. I'll be happy to share how I rigged it when I figure out the final design (with part numbers and locations).
BTW, the Oakland Estuary is VERY narrow. It's NOT a good place for practicing spinnaker sets, gybes and douses. And inside gybes take up a lot of searoom, more than outside gybes (at least the way we were doing them). We got ourselves all flumoxed up a few times. But the sail is so small and easy to manage that we were able to douse it in under 30 seconds, and stay out of trouble.
Fair winds, Judy B
Additional comments:
There was a P19 further out the estuary last time we used the asymm. I didn't recognize the boat, so I don't know who it was. They were sailing wing & wing down the estuary.
We were going MUCH faster downwind than they were, that's for sure. They were bobbing along. We were semi-planing at times, with boatspeeds ranging from 4 knots to 6+ knots through the water (according to my SpeedTech knotmeter)