What is the best rig tension in different weather conditions for a Beneteau 40.7?
Dan Dickison responds:
The general rule of thumb regarding rig tension for performance is that you want a tighter rig for windier conditions and a looser rig for lighter winds. Of course there are several other factors that you should consider regarding rig tension, and the most important of those is sea state. If you've got a lot of chop, it often helps to have a fairly loose headstay to develop sag in the luff of your headsail, which will give that sail some additional power for punching through the waves. Remember, however, that choppy conditions are usually a result of big breeze, so there's a twist to the tuning the rig appropriately. In the case of chop, you'd want relatively tight shrouds and a somewhat loose headstay.
Now the situation becomes even more involved because of the kind of rig you have. The standard rig for the 40.7 is a 9/10ths, triple-spreader set-up with slightly swept spreaders. The first step in rig tune is to make sure that the mast is in column. In this case, that involves tuning not only the upper, lower, and intermediate shrouds, but also the diagonals that stem from the spreader tips upward to the mast.
Once in column, you want to induce the proper amount of prebend in the mast for the given conditions. Generally speaking, you want more prebend for the windier conditions because prebend tends to flatten the sail. To accomplish this, ease the lower shrouds relative to the uppers and loosen the headstay slightly.
I suspect that you can obtain some fairly specific rig-tuning information that has already been documented for the 40.7 by speaking with sailmakers. A good first step would be to contact the folks at Beneteau to see if they can steer you in the right direction. As an aside, I witnessed a well-raced Beneteau at the Acura SORC in Miami last winter, and I suspect they've got this subject figured out. The boat was called Wired, and it's owned by Rob Weed from California. Perhaps if you contact him he'd be willing to talk with you about the way he and his crew tune the rig on their boat. (The folks who monitor www.beneteauusa.com can probably put you in touch with him.) You know what they say, there's no arguing with success. Good luck.