Submitted on July 14, 2007 by John Marken

Question: Hello,

My Bro and I race an F27 corsair tri in the northwest. We have a square top main of Kevlar with full battens. It has been a very well behaved racing sail, feels quite powerful. Also, even at four years it is still in great shape (we roll it on the boom, not flaked). Trouble though, the set of full battens keeps us from using roller reefing as
its tough to keep the battens even with the boom so they aren't bent. Could a sail be designed with shorter lower battens that would allow roller reefing without sacrificing the power of the sail we've come to enjoy? Would light air performance suffer?

Answer: Dear John -

It is possible to design a full batten mainsail that will work with roller reefing. In order for the battens to lay flat on the boom the tack angle must equal 90 degrees so that luff when rolled will naturally want to lay at the gooseneck; in addition the lower battens that are rolled on the boom while reefing have to be angled so the luff end is slightly higher than the leech end (backwards from a normal sail design approach for full battens); the reason for this is that there is more material on the luff when rolled, thus the higher the batten is in the sail this angle increase to compensate for the added material on the luff.

The first suggestion of making the lower battens partial leech battens would work as well but the angle of those battens is still critical and the sail would not be as durable or stable as a full batten sail.

Roller reefing can be hard on the sail and should always be accompanied by finishing the reef with tie downs at the tack and clew (similar to jiffy or slab reefing). It is very hard on the sail to let the loads ride on the leech or luff without a solid connection point to the boom. In my experience we have always used the grommets on the sail for slab reefing to tie the clew down and out, as well as the tack down and forward after the sail is rolled on the boom. In this way it is sort of a cross between roller and slab reefing, if the new tack and clew are not secured tightly the sail shape will suffer and you are almost certain to damage the sail.

Please let me know if you have any other questions.

Regards,
Mat Bryant

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