Slieve McGalliard wrote:

As with the Coromandel, I have just run the measuring stick over the few rough Kingfisher 26 drawings I could find and again seem to find that the junk rigged version has heavy weather helm built into the design. Are we to assume that those who planned these rigs had no regard or understanding of rig balance, and probably worse, that those who have been sailing them have not questioned the balance and performance?

If this is the case, are we going to find that a lot of the other older professionally rigged junks are also suffering from the same malaise?

I just hope that I've made a mistake somewhere, and that this is not the case.

Peter Scandling sailed with me today, and I found that 

1. The K26 Tara's battens are very small in diameter, and probably date from the time that Sunbird was using its customers as guinea pigs to see if flexible battens worked. They didn't. What happens is that they bend into a semicircle that puts the draught much too far aft. This will markedly increase the weather helm and drag the boat sideways, not forwards.
2. The sail is not the original, so when Clay Everington made an Atlantic circuit in this boat, she may well have had battens of a suitable size, and this "experiment"  may have happened later on.
3. The mast does not fill Peter with confidence. It is far too flexible, and he thinks it unfit to go offshore. He talks of replacing it with a tapered pole from ALC, similar to mine and probably a size or two larger.
4. In which case, it makes sense to go for a higher AR sail, which will push the centre of sail area further forward, decreasing weather helm and increasing performance.
5. As well as rig troubles, the rudder is very stiff, as well as ineffective. A good case can be made for a transom hung rudder to a better design.

David Tyler wrote:

What puzzles me is there must be plenty of JR Newbridge Pioneers and Kingfisher 26s sailing around, apparently without cause for complaint. Surely they can't all be accepting excessive weather helm? 

 Good question, David. I fear that the owners of these boats have not been spoilt with high performance of their boats, after 20 -30 years with flat ('hi-power') sails. Even the fitting of H-M sails with hinged battens must have felt like an improvement?

Arne

David Tyler wrote:

«IMHO, sails with a lot of balance area are very good for going downwind, but not much use for anything else (I exclude split junk sails from this sweeping statement, as they are playing by a different set of rules). When the mast is to leeward, we need to get it into the separation bubble which lies quite close to the luff.»

I too feared that a big (mast) balance in a cambered panel sail would lead to bad performance on the mast-to-leeward tack, so I kept the balance between 8 and 12% in my sails. However, Paul Thompson has clearly demonstrated that 18 -22% can be used, and his La Chica still performs well on both tacks. After the first couple of trial sails of the new JR on my IF, Ingeborg, I shifted the sail forward from 10-11% to 14-15% balance, and it works fine. Only fine instruments would tell if, or how much performance I lost. My hunch is that I gained more than I lost as the change improved the helm’s balance. Nevertheless, this myth of the bad tack is not easy to bust.

David also wrote:

«The Hasler planform puts the area of the upper panels further aft than sails with a lower angle of yard, and this will contribute to weather helm; getting worse the more you reef. This, along with the longer luff, is a major part of my thinking in Weaverbird's sail.»

I have never had a problem with this. I am on my sixth JR with some sort of H-M planform. They all reef beautifully. If anything, any weather helm is a bit reduced as I reef (not much). It may well be that the top section of my rig sits further aft  -  I haven’t checked  -  but it is no problem. Maybe this is the reason why I don’t end up with a bad lee helm when reefing: It is easy to forget the windage of that (bare) mast.

Conclusion:
Nowadays there is little reason for building the sail with a Johanna-style planform to minimise balance at the mast. When I still build them this way, it is mainly for three other reasons:

·         The boats I have converted has more or less forced the masts to sit well forward, because of the deck or interior layout. This again forces me to fit the sail with moderate balance to avoid lee helm. A tall yard angle (70°) is a natural result of this.

·         The high-peaked Johanna-style sail lets one set the biggest and tallest sail on a given mast length. Remember; one can always reef that sail, but one cannot reef the mast.

·        I have found the 2-3-panel top section to be a very efficient hard-weather sail, downwind as well as upwind. If properly rigged and with the FUP (fan-up preventer) set, it should be as trouble-free in use as any (still only 5 running lines).

Arne

 

David Tyler wrote:

IMHO, sails with a lot of balance area are very good for going downwind, but not much use for anything else (I exclude split junk sails from this sweeping statement, as they are playing by a different set of rules). When the mast is to leeward, we need to get it into the separation bubble which lies quite close to the luff. When the mast is to windward that doesn't apply, though. My feeling, without much evidence to back it up, is that you probably have a similar situation to that of Jilly, the Vertue that wouldn't tack and sailed very poorly, until Gp Capt Smith replaced the HM sail with one of his Fenix-style sails: high AR, not much balance area. He got some camber from the fanned shape, but that didn't make it a  very good cruising sail, as the batten stagger when deeply reefed was extreme, so I wouldn't go this route.

David, LC has rather more balance than most in both of her sails and I cannot say it hurts her windward performance at all. I did wonder when I first tried it but in practice I cannot say that it's a problem. Any one in NZ who has sailed with me knows that LC goes to the windward rather well... What I'm getting at is it's more a theoretical disadvantage than a real one.

David Tyler wrote:I wouldn't make another flat sail, and I wouldn't add more area, making for a lower AR.

Fear not, if I'm making a new sail it will definitely have camber somehow. But I also suffer from poor downwind performance in light airs — a problem for cruising — so I probably will add more area. It's very likely that my next sail will be made of polytarp and duct tape so I can be sure of the balance before I start serious sewing.

The exact details of my boat are probably best kept in another thread, such as “New Sails for Tammy Norie”. I'm just keen to extract relevant experience here, for the benefit of all.

I agree that the split rigs and aero junks are playing by different rules, and with Arne's earlier statement that they're more like two sails. Slieve's reference to model yachts is fascinating.

Speaking of which, look at these go!