Mylar Sails - a report from Jay Renehan in Seattle

The Renehans used the new Mylar sails loaned by Richard Spencer on a beautiful Thursday night in Seattle. Conditions changed slowly through the night from about 12 knots to about 5 knots, in relatively flat water. We sailed with the forestay about 3/4" longer than it should have been for the evening (did not remove the bottom rotator) which saved some rigging time of the forestay. There was good competition from Buchans, two Lanzinger boats, Cole, Andy/Erin, and about 6 others (regulars and newcomers). The racing was generally very close until the wind got light.

Everyone agreed, including the I-14 and Laser sailors, that the sails look cool! The visibility while sailing is nice too.

Sailing upwind: There was one particularly long beat after a long, tactical and close downwind leg. Lisa and I were both be sitting on the tank, a condition where we are typically fast compared to the top boats. We were distinctly faster and higher than all other boats, no question. On that leg, the entire fleet was heading to the right on port tack in a staggered line, it seemed that most boats had clear wind. I believe the wind was approximately equal for all boats, and the water was flat. Chris and Molly's 10 or 12-boatlength lead on us was changed to a 2-boatlength loss to us, and the boats behind became further behind. If our rake had been correct, I am certain we would have been even higher and faster. For the last race in the dying wind, we started clear to leeward, went the "wrong" way on purpose for the first beat, and were first at the mark.

When sailing the boat, the sails seem "stiffer" and the boat seems to responds faster to puffs, and requires less adjustment (especially in the jib) during changes in windspeed. Essentially, it seems that the boat is easier to sail because the "optimum" sheeting of the jib does not change as much for the Mylar sail for a change in windspeed. It is a similar difference as changing from a very old Dacron jib and a brand new Dacron jib. It is nice to be able to see the jib leech while sailing upwind, to immediately know whether the sail is too tight.

Downwind: Last night, the downwind sailing (runs only) was tactical and close. I did not perceive any significant difference in speed that could be attributed to the sails. There were too many other variables and the speed differences were mainly due to wind speed.

My perception of the mainsail is that the Mylar main is does not have as much effect on the performance or sailing style than the jib – the upwind sailing is about the same. Downwind, it is easier to have too much vang on with the Mylar main, a result of the shape and the cloth, no doubt.

Other observations: The Mylar selected is lightweight and thin. I am not an expert on this material, but I do wonder if the material is sufficiently durable to withstand "abuse" loads. For normal Tasar sailing conditions, the material is certainly capable of performing just fine. But it seems that if something unusual happens (capsize, pole pokes into the cloth, failure of a jibsheet shackle) and the breeze is on, that the material might suffer considerably more than the current sails, where there are more battens in the main, and the jib could be furled. I'm sure we will miss the furler a bit, but we'll get over it. I don't know if the reduction in number of battens will have a measurable effect on the life of the mainsail, or if the change in material will have a bigger effect than the batten change. A Dacron main can remain competitive for many seasons.

My recommendation for the class is to implement the change with as little impact to the sailors as possible. We really don't want or need improved performance. And we really don't want to lose participation or alienate sailors that may not upgrade in the next 5 years. I heard something about a change to the rotator associated with the sail material change. In my opinion, this sounds like unique/custom hardware, priced accordingly, with seemingly no benefits (Note: this change is no longer being considered - RS). I would recommend we move forward with something very similar to the setup we used last night, which did not require custom hardware– the setup we used provided by Richard was excellent – I would guess it could be done for less than about $US 50 parts (2 small blocks, line, and a forestay) available at any chandlery. And a single, capable, world-wide supplier of sails should be able to provide cost and quality the sailors demand.

And the sails look cool.

Jay Renehan

Posted 2005-08-22

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