Tack Point/s for Asymmetrics

[sailvi767]

Originally Posted by Abaco

Cotemar,

That chute does not appear to be flying on a Mahe 36. Was it on a Voyage down in the BVI by any chance?

It is a Voyage 440 plus in the BVI. Here is a link to the boat reaching with the same chute last week. The system is easy and works well.

DigiProofs.com - Thumbnail View

[RoadRacer]

Dead link.....

[sailvi767]

I tried the link and it is working fine. It does take a bit of time to load since there are a lot of photo's.

[sandy daugherty]

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[sandy daugherty]

I've seen a couple of solutions to shift the assymetrical chute (or a code Zero) tack laterally. A Stiletto 30 had a sturdy 7x19 wire between the bows, and the sail tacked to a wire sheave that ran on the wire. There were traveller control lines led back to the cockpit. The loads were quite high, but the control was elegant. The code Zero could be carried effectively to a much higher angle because shifting the tack downwind tightened the sheeting angle.
A second solution is a swinging bowsprit. Mine is a long carbon pole with a spinnaker pole socket mounted forward of the mast. It can be adjusted by lengthening or shortening the wisker stays (that run from the front of the pole down to the bows just at the waterline.) These require a significant winch to adjust under load, but since my cat has no gull striker, the pole is free to swing from side to side on top of the tramps. I fly a furling screacher from this pole, and have not tried the spinnaker on it.

[thinwater]

Originally Posted by sandy daugherty

I've seen a couple of solutions to shift the assymetrical chute (or a code Zero) tack laterally. A Stiletto 30 had a sturdy 7x19 wire between the bows, and the sail tacked to a wire sheave that ran on the wire. There were traveller control lines led back to the cockpit. The loads were quite high, but the control was elegant. The code Zero could be carried effectively to a much higher angle because shifting the tack downwind tightened the sheeting angle.
A second solution is a swinging bowsprit. Mine is a long carbon pole with a spinnaker pole socket mounted forward of the mast. It can be adjusted by lengthening or shortening the wisker stays (that run from the front of the pole down to the bows just at the waterline.) These require a significant winch to adjust under load, but since my cat has no gull striker, the pole is free to swing from side to side on top of the tramps. I fly a furling screacher from this pole, and have not tried the spinnaker on it.

I built something similar to what Sandy describes for my PDQ 32. Like Sandy, I too previously owned a Stiletto and my PDQ design was an up-graded version.

http://sail-delmarva.blogspot.com/20...ning-tack.html

However, I took the traveller back off after a few months, preferring the simplicity of a single point. Though it worked mechanically, I found it was slower and I simply didn't use the feature. I should have known this, I suppose. I never used the traveler on the Stiletto either. Jibing down wind was faster and more fun, and the genoa was as fast up wind as the code zero due to lower lee way.

Additionally, the Stilettos and PDQ 32s are beach cat rigged (no back stay) and cannot ease the main out far enough to sail deep without stalling.

I hate to be the contrarian voice, but I don't think moving it is going to help. You will be able to sail deeper and slower.

[Abaco]

Sailvi747,

I thought it looked familiar. I sailed with Mark to Key West back in Sept. when we borrowed it. That tack bridal worked very well. Have you thought about cutting the line so they are seperated as opposed to the single line you have right now. I really like that set up.

[thinwater]

A few thoughts about the 2-rope bridle, from my testing:

• It only moves the tack a few feet to windward, not clear to the bow. Since the leeward rope is slack, we can see that it has reached its limit.
• It will have to be adjusted at every jibe.
• The support of the tack is not as good as a prodder in lumpy conditions; the luff will bounce more.
• In fact, if the wind angle is considered, it offers no greater windward projection than a prodder ~ 4 feet long.
• It offers less projection than a prodder if the wind is close to the beam.

All of which explain why fixed sprits are so popular. The down sides are weight, docking , sometimes length charges, and burying the prodder in a wave.

[sailvi767]

I have looked at cutting the sheet on the rig. The problem with cutting the sheet is that when running dead downwind the assymetric does rotate well out in front off the boat. The chute is within a couple of feet of the hull and that tack point line is near vertical. The other tack point line has to be very long with a 4 to 1 purchase to allow the chute to rotate out front and to the side. If I cut the line into two lines each would have to be much longer then the one continuous line. Also there is less chance with the one continuous line of it dropping in the water and reaching the props if they happen to be running. I have seen this type of system on many cats and it seems to work well. It works very well on the Voyage 440 Plus because of the long waterline length of the boat and long bows. This reduces the gains from a Sprit. Every boat will be different. A short waterline cat that is heavy relative to length like the Lagoon 420 or 440 might be better off with the Sprit.