|
With all due respect to you and your sailmaker, if you understood what your sailmaker was actually telling you then you really need to talk to a more knowledgeable sailmaker.
In a properly made mainsail, the foot provides absolutely no support to the mainsail on any point of sail. Properly made the foot of the sail is a wing shaped shelf. That shelf should be configured so that it places no load on the sail (if it did it would distort the shape of the lower panels of the sail). The shelf is onlt there for aerodynamic reasons to act as an endplate. Properly set in all conditions, the tack and clew cringles take all of the foot loads in the sail. The shelf should never be under a cross load. Go sail on a bunch of well sailed boats with shelf foot mainsails and look at the shelf on a variety of points of sail and I assure you that you will not see the shelf ever providing support the mainsail in any conditions.
Even on shelf-less mainsails, the foot provides minimal support for the mainsail and in fact increases the bias loads on a mainsail therefore theoretically shortening its lifespan.
It sounds like the Chesapeake where I live and sail, has very similar summer winds as you do. I race and sail on a lot of different boats in any given summer. Around here the crack race boats change their mainsails every year or two but that has absolutely nothing to do with whether they have a loose or shelf foot mainsail. It has to do with the need for the absolute best sail shape, the light weight sail cloths that are typically used, and with the sheer amount of use these sails get in a year of being campaigned. Both the J-22 and the Farr designed 40 footer that I have been crewing on for the past few years replaces their mainsails each year. Both have shelf foot mainsails. I am a mainsail trimmer on both. I spend a lot of time looking at those mainsails. At no point in the wind range or on any point of sail is the out haul eased enough that the foot exerts pressure support on the sail. On my previous boat (a Laser 28)I used a loose footed mainsail for over 11 years. It was still competitive in its last year that I used it (6 firsts, two second and a third and the third was because someone misread the race circular and so we rounded the wrong mark close to 600 feet upwind of the right mark).
There are a lot of reasons why you might want a loose footed or shelf footed mainsail. Durability isn't one of them. The load distributions in either type will be virtually the same if both sails are made properly. On both types of sails, the full foot loads on the sail are carried by the clew and tack. If the sail is properly engineered to properly distribut the loads, this has no impact on durability and so both types of sails have equal lifespans. If your sailmaker says otherwise you really need to talk to more knowledgeable sailmakers.
(Two minor points here:
-One reason that some racers have gone to loose footed sails is that it has become increasingly popular to carefully roll the mainsail and remove it from the boat to increase its lifespan. (Heat shortens the life of the higher teck laminates) -When I first saw your post, I happened to run into two sailmaker friends (one from North and the other feom Doyle)and mentioned that your sailmaker said that loose footed sails have a shorter lifespan. They laughed and said that you must have misunderstood what your sailmaker told you because obviously your sailmaker would know better than that.)
Respectfully,
Jeff
|