After Andy Simmons let me try out his second prototype White Xtra sail on the Fal Estuary in Cornwall (see pages 11 and 12 in Perihelion 122), he kindly loaned me the sail for the rest of the season. In return, I offered to write a short article on my experience with the sail for the next issue of Perihelion.
The White Xtra sail is made from a white Dacron cloth which is a more flexible material than Mylar, and it has its own logo consisting of a White ‘X’ in the centre of the Orange Comet symbol. Although the White Xtra sail fits the spars for the Mylar Xtra sail, and also has three battens, there are some differences between the dimensions of the two sails, as can be seen in Figure 1, where my Mylar Xtra sail has been placed over the White Xtra sail with its head and luff aligned with those of the White Xtra sail. Compared to the Mylar Xtra sail, the White Xtra sail has a longer luff, foot and leech giving it a slightly increased sail area of a few more square feet along the foot of the sail and in the roach.
The slightly greater roach area means that the leech of the White Xtra sail extends aft of that of the Mylar sail. Although the first batten below the head of the sail and the leach at that level coincide between the two sails, the second batten and third batten in the White Xtra sail are a further 5 cm and 8 cm respectively below the corresponding battens in the Mylar sail, and at these levels, the leech on the White Xtra sail extends aft by 3 cm and 3.5 cm respectively. These two battens in the White Xtra sail are about 10 cm longer than those in the Mylar sail. At the level of the clew on the Mylar sail, the separation of the leeches has reduced to about 1.8 cm. At the tack and at the clew, the foot of the White Xtra sail is about 5.5 cm and 11.5 cm respectively below the foot of the Mylar sail, and the foot has been extended by a couple of centimetres beyond the foot of the Mylar sail to more or less the maximum foot length which the Xtra boom will accommodate. When the White Xtra sail is hoisted, these changes in sail design have the effect of lowering the end of the boom compared to the Mylar sail, but still allowing more headroom than the Standard sail. One further difference between the two sails not visible in Figure 1 is that the eye at the tack of the White Xtra sail (through which the downhaul is fed), is a couple of centimetres above the eye on the Mylar sail. Compared to the second prototype White Xtra sail, the production version of the sail will have a larger window and the luff has been cut with slightly more (ie fuller) depth.
Rigging the White Xtra sail is exactly the same as the Mylar Xtra sail. However, because of the closer 
proximity of the clew of the White Xtra sail to the end of the Xtra boom, it is advisable to dispense with the block and spring clip, and thread the outhaul, shock cord and tie-down directly through the eye at the clew of the sail (Figure 2). Alternatively, the White Xtra sail can be rigged on the Standard sail’s boom thereby allowing the clew outhaul to be used with a block and spring clip. The top mast is now available with the halyard block secured to a bracket riveted to the mast head and extending upwards at an angle thereby allowing the head of the sail to be hoisted about 4 cm higher than with the halliard block secured to the eye at the mast head, as shown by a comparison of Figure 3 with Figure 4. Because the luff of the White Xtra sail is about 5.5 cm longer than that of the 
Mylar sail, 
the gain in height provided by this bracket means the tack of the White Xtra sail is only about 1.5 cm lower than the tack of the Mylar sail and there is still enough travel on the downhaul. Not only can a top mast with the halliard block on a bracket be used with the Mylar Xtra sail, it can also be used with a Zipper Standard sail.
I used the second prototype White Xtra sail at the Association Championships held at Attenborough (Figure 5), and at the Open Meetings held at Littleton (Figure 6) and Merthyr Tydfil (Figure 7). When analysing my results at these events, I think it is only fair to consider the following factors:-
My results at Comet events over the years tend to support the notion that I seem to do better in strong winds, and then progress (or should that be regress?) from worse to utterly abysmal as the wind gets lighter. The strongest wind I raced in with the White Xtra sail was the last race (no. 4) at Littleton and I finished in the highest place (3rd) in any race at these three events.
- Due to the change in my personal circumstances (i.e. moving house to a different part of the country and all that entailed), I have not had the benefit of weekly club racing this season, and I arrived at each of the few Comet events I attended this year dismally out of practice. For instance, in the first race at Merthyr Tydfil, I rounded the first windward mark in 2nd place, but had dropped to 5th by the finish, and after rounding the first windward mark in 4th place after the start of the first race at the Association Championships, I finished the race in 20th position!!
Two Open Meetings and one Championship hardly provide a rigorous evaluation of the sail’s performance, but they have given me a chance to try the sail out in conditions which varied from light and very testing (Association Championships) to gusts reported to be as high as 35mph (race 4 at Littleton). In the very strong winds, the sail had all the same benefits of balance, controllability and easier boat handling as provided by the Mylar Xtra sail. In the very light conditions over both days of the Championships, I found the luff of the sail difficult to “read” on the beat, but I then found it a lot easier and the sail seemed to have more “power” when I slackened the foot right off (see Figure 5). The slightly greater depth cut into the luff of the production version of the sail may help to address this point. In any case this may be more a reflection of my own inherent difficulty (or should that be cack-handedness?) in very light conditions – Paul Hinde borrowed my boat and the White Xtra sail for the last race at the Merthyr Tydfil Open Meeting when the wind had dropped to very light, and at one stage, he was in 2nd place!
An acid question to consider is how the White Xtra sail compared to the Mylar sail. Henry Jaggers and John Sturgeon used their Mylar Xtra sail at the Littleton Open where in race 1, I finished in front of both of them; in race 2, I finished behind both of them (I was over the line at the start and it was the lightest wind of the day – well, I have to have some sort of an excuse!!); and in race 3, I finished in front of both of them. I also raced against them in race 2 at Merthyr Tydfil when they were using their Mylar Xtra sail, and I finished between them. Hardly enough data to draw any firm conclusions, but perhaps the least you can say is that it was as quick as the Mylar sail in wind strengths which varied from “light” to “fresh”!
In theory, the more supple white Dacron cloth and the slightly greater sail area should mean that the White Xtra sail is competitive against the Standard sail over a wider range of wind speeds than the Mylar sail. If so, it should help to address the concerns I raised in the Spring 2015 issue of Perihelion (no. 114, p22-23) about not being able to change rigs during a one-day event or even between days at a Championship. In my opinion, the White Xtra sail satisfies the aim of giving a fully rigged Comet a more modern look. I have enjoyed the novel experience for me of trying out a brand new sail design (thank you Andy!), and I have been sufficiently impressed by its potential to buy a production version of the sail. I look forward to the time when one of the active “top” sailors in the fleet decides to compete right through a season with a White Xtra sail, thereby giving it a more extensive and objective evaluation than I have been able to in the last couple of months of the 2017 season.
Peter Mountford C864
Figure captions:-
Figure 1. My Mylar Xtra sail placed over the White Xtra sail and the two sails aligned at the head and along the luff.
Figure 2. The clew of the White Xtra sail attached directly to the outhaul, shock cord and tie-down with the foot of the sail not quite at full tension showing the proximity of the clew to the end of the Xtra boom.
Figure 3. The position of the head of the White Xtra sail in relation to the head of the top mast when the halyard runs through a block secured to a bracket riveted at an angle to the head of the top mast (NB the curved wire loop appearing to protrude from the front of the mast is actually the safety strop of the trailer which was underneath the mast!).
Figure 4. The position of the head of the White Xtra sail in relation to the head of the top mast when the halyard runs through a block secured to the eye at the mast head.
Figure 5. Light conditions at the Association Championships (Attenborough SC).
Figure 6. In a very much stronger wind at the Littleton SC Open Meeting (race 4 – the bent burgee was the result of a full inversion capsize in the previous race!).
Figure 7. A comparison with John Sturgeon’s Mylar Xtra sail at the Merthyr Tydfil SC Open Meeting (have I got the foot too loose on a beat at that wind strength?).