Using Battens in Roller Furling Mainsails and Headsails

A reader asks:

I have a 1997 Beneteau 461 with roller furling main and genoa and need to replace both sails. The main is relatively new but is poorly shaped – the leach cups, etc. I read that you use vertical battens in BEOWULF’s roller furling jib. If you used a 135% genoa instead of a 100% jib would you still use vertical battens or is their application only for jibs?

The British firm, Maxiroach makes roller furling mainsails (and headsails) with full length vertical battens that appear very attractive on paper. Doyle Sails makes a swing batten main. Quantum makes a main with vertical battens. Could you give me any advice on which of these products is the best or recommend someone that may know.

If you were going to buy a new roller furling main ( I know this is not likely to ever happen!) who would you go to for advice on the best way to go?

We asked Dan Neri of North Sails to answer this question:

The Dashews asked me to offer some advice about options for battens used with luff-furling sails. I currently work for North Sails developing products for the cruising market so I am familiar with the few products that you mentioned in your email message and my opinions are at least a little biased. I have not seen a Maxiroach sail or a Doyle Swing-batten mainsail in action. I do have quite a lot of experiance with vertical battened headsails and Stowmains both with and without battens.

Vertical Batten headsails – Vertical battens solve some problems for headsails that do not overlap the rig. When the head section of any sail gets too narrow the sheet loads are directed right up the leech, so the sail can’t twist open at the top the way it should. A sail with no battens has a negative curve cut into the leech so the narrow head of the 100% jib gets even more narrow. When the sheet is loaded for upwind sailing, the head gets a tubular, tight leeched shape. The addition of the battens allows the sailmaker to build the sail with a straight leech or a slightly positive roach on the leech. The benefit is extra sail area compared to the same sail with no battens, and a more efficient, twisted leech shape at the top of the sail.

For a lower aspect sail, like your 135% genoa, the head is already wide enough that it won’t tend to “tube-out” if the sail is well designed. The battens would not be quite as much of a benefit. Also, it is not a good idea to install battens in an area where they will impact the rig during tacking or gybing manuevers. Batten pockets are the most high maintenance part of any sail and if you put them in a spot where they might hang up on the shrouds, spreader ends or mast hardware, you are just asking for trouble.

Vertical Batten Mainsails – Vertical battens have the same benefit in a mainsail that they do in a headsail. The sailmaker is able to build the sail with more area and a much more efficient shape in the head sections. In general, the longer the battens are, the more support they will add for the extra sail area. However, there are some tradeoffs. Battens are bulky and that bulk makes the rolled up sail a larger diameter. Most stowmainsails are a pretty tight fit in the mast cavity. The farther your vertical battens project toward the foot, the more space they will take up where the sail is widest. My guess is that the addition of four battens extending all the way to the foot, as would be the case with the Maxiroach setup, would make the rolled sail too fat for the mast. The solution would be to build the sail from a lighter fabric. In very general terms, lighter fabric usually means less rugged fabric.

Any vertical battens present some amount of hassel when installing or removing the mainsail because they prevent the sail from laying on the boom or deck. I can’t think of how you would deal with the full length battens in a Maxiroach setup which, in the case of your 46 footer, would be as long as 40′. You might be able to hoist the mainsail without the battens, wait for a perfectly calm day and then roll it all the way out and shove the battens in from the deck. Then I guess you would need a plan for how to get the sail down in the event that the mast furling mechanism failed while you were underway. Whether you remove the battens first and then the mainsail, or mainsail first and then the battens, you are going to have your hands full in any adverse conditions. I am sure the Maxiroach people have thought of these issues so they probably have better answers.

Swing Batten – Again, I have not ever seen one of these sails. On top of that, I am a cynic by nature. I don’t like the idea of any batten that is not securely fastened to the sail at both ends and my impression is that with the Swing batten there is a fair amount of complication for not much benefit. The sail probably works great in light air conditions. In heavier air I would worry about the extra roach area flogging with no support while the sail is being rolled in or out. The batten will be hanging on the part of the sail that is flogging the most, acting like a knot on the end of a whip. After several hundred flogging cycles my guess is that some part of the hinge or sleeve is going to give up. How bombproof is the string mechanism? What happens if it breaks?

The sail in the advertising looks great. I would suggest that you ask the Doyle guys how well tested the product is. If they have made a bunch of them that have been used harder and longer than you intend to use yours, then they have probably worked out the duribility issues.

In my opinion, the best solution for a stowmainsail is to build the sail out of the appropriate weight fabric with a straight leech, and to use battens that are no longer than required to support the area that would have been cut away on a sail with no battens. In the case of your boat that would mean 4 battens, each about 4.5′ long. You can specify a sail with positive roach area. That will require longer battens and the sail shape will deteriorate a little sooner. There is no single correct answer to the amount of roach area or the batten lengths.

No matter which of these mainsail products you choose, your new mainsail will no doubt be a big improvement over the one you are using now.

Regards, Dan Neri.

Posted by Sarah.Dashew  (August 17, 2001)

2 Responses to “Using Battens in Roller Furling Mainsails and Headsails”

  1. M.Lincoln-Smith Says:

    Some years ago I purchased a No.3 high aspect furling jib with Harken Roller Battens – This short footed jub which was non overlapping had a positive roach. It proved very successful indeed. It was easy to winch in, did not back wind the main and set very well to windward. In gusts you could watch the top of the leech open and close. The battens were Harken, furled up with the sail. The sail was made by the then East Coast Sails, Walton on the Naze, UK. David Stern was the then sail maker, a very able person indeeed.
    I am now wanting a sililar sail to fit my 33ft masthead sloop, Westerly 33.
    Anyone know if this system is still used?

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