Sail Tuning - Backstay Tension

Posted By: Gene Bragalone - #485/5.2
Date: 6/24/07 6:26a.m.

Report: outside forum guidelines

In Response To: Mast Bend (Larry Munro)

I had contacted North Sails with regard to a tuning guide for the Harpoon 5.2. Their response was that they did not have one specifically for the 5.2, but they did provide me with some useful information. (They DO have comprehensive guides for MANY other boats, which can be very helpful so pass that on to friends or use it for your other boats.) What they had for the 5.2 could be very helpful. It helps determine the rake (forward to back positioning) of the top of the mast. With that comes some information about shroud tension and that it should be nominally set at 200 lbs. While this not easy to measure without a gauge, which measures line-bend-under-pressure, be advised 200 lbs is not "slack" and if you tap the shroud the result should be a little bit of a low "twang", rather than a rattling thud or no sound. (And while 200 lbs sounds like a lot, it is not, compared the the actual pressure under load.) The forestay, however has a considerably wider angle to the mast and is under far less pressure under way than the shrouds, even with the jib riding on it, so I would not recommend trying to achieve the same tension there .. it wouldn't be achievable anyway without exceeding the specified tension on the shrouds. Point is, just don't try it. It might be worth checking your set up for rake. It could explain why you might be having weather helm or lee helm difficulties, and possible could help with pointing problems. (Remember, however, to mark where you were set before adjusting ... just in case you don't like a new set up ). My email exchange response is shown below .. (BTW, I don't know what "4:1 on jib halyard would be nice, or 3:1." means. If someone could enlighten me I would be grateful) >>>>>>>>>>>>>>>>>>>>> --------------------- <<<<<<<<<<<<<<<<<<<<<<< Gene, Your note was forwarded to me as we are the builders of the North Harpoon 5.2 sails. Our web site is at http://northsails.com/gulfcoast/, and you can follow the link to the Harpoon 5.2 prices and info. At this point we do not have a tuning guide posted, but here is some basic info that I have gathered. If you have any question just email me. Thanks, Ethan Rake – using the jib halyard, establish a radius off of fiberglass molding at mast step, swung forward to headstay, and then measure down to the headstay pin. Range is from 3” to 5.5”, with shrouds at 200 lbs. In-hauling the jib in light conditions would be good. 4:1 on jib halyard would be nice, or 3:1. Ratchet on mainsheet. Different jib cleats for better tacking. Ethan Bixby North Sails Gulf Coast 727-898-1123 727-385-7775 (mobile) http://www.northsails.com/gulfcoast Skype: ebixby