Rigging Tension

[Terry Chiccino]

A question for those who know. I bought my Mac 2002 26X in October 2003 from a family who had only used the boat as a powerboat and consequently didn't know anything about rigging the boat. What should the shroud tension be? I think the lines are 5/32" (does that sound right for the 26X). Is there a difference in tension in the upper and lower shrouds I called the manufacture and thet told me tight but not tight enough to play music on. Figuring everything is relative I considered that to be no answer at all. Any help would be appreciated!

[Frank C]

Official guidelines are that you need 5% of breaking strength to just remove the wire's innate stretch. Click the "Featured Articles" button. Bruce's article says 15% for the uppers and 10% for the lowers, plus he gives you all the procedures.

I used a Loos gauge, but never got even close to the "recommended" tension of 500# (about 15%) for the upper shrouds, more like 300+ (sorry, don't remember exactly). I recall I managed over 200, but less than 300# for the lowers.

However, I also believe that the Mac's hull is not rigid enough to handle normal guidelines for rigging tension. Note that there are no reinforcing bulkheads in the Macs, the centerboard trunk is as close as we get for a reinforcing structure. As long as heavy winds create only mild looseness (not true slack) in the lee shroud, you should be ok.

So there ya go ... that factory recommendation, "...tight, but not too..." is pretty scientific after all, eh?

[Terry Chiccino]

Hey thanks for the advice. I guess I should take a look around this website before I ask any more questions. I see in your reply that you are out of Alameda. We bought the Mac to put her on the San Francisco Bay and are looking forward to the experience. I'm anxious to get this boat out on the water but with winter setting in I can only get ready in the driveway. Mabey we'll see you out there this summer!

[Jack O'Brien]

I have a 2000 X and am happy with my riging.
Get Loos & co. Tension Gauge standard model Part No. 91 for cable sizes 3/32, 1/8 & 5/32". West Marine and others sell it about $45.
The forestay and backstay are 1/8". The shrouds are 5/32". I followed the mast rake, bend and other instructions in the Mac Manual. I used a plumb-bob on a line from mast top to get bend. I used the Mac shroud adjusters and trial and error. All my shrouds are the same tension i.e. 180 to 200 pounds measured at shoulder height. My backstay has minimal tension on it but I unhook it to unpin the forestay. I can unpin the forestay with firm, but not max, tension on the raising gear/winch with sail on the furler.

[Frank C]

Hey thanks for the advice. .... Mabey we'll see you out there this summer!

Terry,
I'm looking forward to getting back on the Bay when weather improves. The 26X is a perfect boat for it, since steady, strong winds permit her to perform her best. I actually live in Danville and store the Mac in Alameda.

You can reach me by email through owner profiles. Heath's new board has better masking of personal data than previously.

[Terry Chiccino]

200 lbs. sounds about right. Does it make a difference where you put that gauge on? I went and bought on of those Loos gauges the other day I figured it would come in handy what with constantly raising and lower the mast (I keep my boat at home in the garage).

[Steve K]

Yep, when I first got my X boat, I got the same answer from the factory, as far as rig tension goes.
Your shrouds should be reasonably tight, so when you're on a tack, the lees aren't noticably slack.
To me, the most important thing is the mast "pre-bend". If you have a completely straight pole, your mainsl will be too baggy all the time. This is because the luff of the main was cut with this amount of pre-bend in mind. You need to get the right pre-bend in the mast, so you will be able to flatten sail, when you need to (very light and very heavy air).
I find that if you follow the manual's instructions for setting pre-bend, you will almost automatically get the shrouds reasonably tuned. I don't, however, carry as much mast rake as the manual calls for. Start with 2 degrees of rake and about 2 to 3 inches of pre-bend. See how this works for your sailing style and conditions and go from there.
BTW, when I adjust my rig, I always have the backstay completely loose. I forget what the manual says about this, but it wouldn't apply to my rig anyway, because I have a split, adjustable backstay.
SK