Maxi Roach Mains / Roller-Furling Booms

Dear Mr. Dashew: I have been using a roach/leech overlap of 20% with no problem of backstay passage, and I have found this conservative, and have had no chafing problem over a six- or seven-year period. Have you used higher percentage overlaps successfully?

I am currently considering the use of a single diagonal batten just down from the head of the sail to get the leech well out, and then downward, with the battens having up to a 50% overlap. By that I mean that if the distance from luff to backstay is one meter, the batten would be 1.5 meters long.

Watching videos of my sail passing the backstay in slow motion plus years of experience show me that the sail “peels” across the backstay from bottom to top. Therefore, once the sail assumes a rounded shape, the battens slide easily across the backstay. Do you think 50% overlap will work, and is this a maximum?

A final question: Have you used roller booms on any of your boats? I am using a roller boom, and this raises some additional issues in the event you have experience or thoughts on maxiroach sails and roller booms. Thanks in advance for your comments. Lowell

Hi Lowell: I don’t think you can make a blanket statement about the maximum roach overlap that will work. It is a question of backstay angle, and of course how hard the wind is blowing. What we have found is that you can get a lot more roach past the backstay than you would normally imagine possible!

If you push the design envelope here, my suggestion would be to add in a first short reef, which would drop the sail low enough so that it would clear in light airs, and when motorsailing. I assume you’ve already got UHMW chafe strips on the sail. If not, these will help too.

On roller-furling booms, the only advantage I can see in these is they eliminate the need to use a sail cover. If the top of your boom is seven feet off the deck, and hard to reach, and maybe overhangs the cockpit, it may make sense. However, everyone we know who has used these says they require careful operation and are subject to all sorts of problems if not kept at the correct horizontal and vertical angles. Bottom line–assuming budget is not an issue, and you do a lot of daysailing, they may make sense. But for sailing on offshore passages I would rather have a conventional boom with slab reefing. Steve

Posted by Steve Dashew  (November 30, 1999)

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