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Submitted
on October 15, 2001 by Scott Bursor
Question: I'm interested
in a big-roached full battened mainsail for my Pacific Seacraft 34 and
I understand from Steve Dashew's book and web page that you are probably
the world's expert on this subject.
Answer: There are some general, mostly common sense, truths about roach overlap with the backstay.
1) The more the
sail overlaps the backstay, the more wind will be required to blow the
sail through the backstay.
2) The softer the battens, the more easily the sail will bend and flop
through. Stiffer battens do a better job of supporting the roach area.
3) The more roach you add, the more horsepower your sail will generate.
4) A well designed, big roach mainsail, does not have any adverse affect
on the balance of the sail plan.
The total amount of roach (area behind the straight line from head to clew) is not so important as the location of the roach. On a boat like your Pacific Seacraft, the roach would have to be designed in the shape of a relatively fair curve so that there is not excessive poke at the top batten. A boat with a very large mast head crane can have more roach poke at the top batten and a boat with no permanent backstay, like Steve Dashew's Beowulf, can have a very aggressive, square topped mainsail.
North Sails has 4 predefined cruising roach profiles. You should consider a full battened mainsail with a "Performance Roach" option. This sail should tack through the backstay in as little as 6 knots of apparent wind. In lighter winds than that you will have to ease the mainsheet a few inches on each tack in order to get the sail to flop through. Gybing is more or less the same story. The sail will clear in as little as 4 knots of apparent wind because the sheet is already eased, but in order to generate the apparent wind speed, you will find that you need to come out of the gybes at a higher angle to the wind in very light conditions.
Aside from the gybing and tacking considerations in very light conditions, there are no real drawbacks to a larger roached cruising mainsail. We have addressed the chafe issues on the batten pockets by using front loading full length battens. The leech ends of the batten pockets are smooth and permanently sewn shut.
The reef locations are predetermined at standard heights. Our standard reefs take away larger chunks of sail area than most sailors are used to in general purpose mainsails. We have learned from our own ocean sailing and interviews with our most experiance customers that when it is time to reef in a cruising context, you want to take away a significant amount of sail area. However, if your style of sailing involves a lot of motor sailing time, you should discuss that with your local salesman. We can adjust your reef spacing so that the first reef is a motorsailing reef. When the motor sailing reef is used, the roach will clear the backstay by about 3" so you can sheet the sail close to center line and won't have to listen to it whacking the backstay when tacking or when the boat rolls in very light conditions.
Regarding ordering a North Sail, your best bet is to contact a North Sails rep in the office that is closest to your boat's home port.
Email North Sails with your question today!
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