MacGregorSailors.com

Finally got around to adjusting the rigging yesterday on my X.
- Replaced chainplate adjusters with turnbuckles
- Adjusted outer shrouds to 360 pounds, inners to 240 pounds. Wanted to get the inner shrouds a bit tigher but couldn't because the turnbuckles bottomed out. They still feel pretty taut. Haven't had the boat out yet to check tension on different points of sail. I still have a little room left on the outer turnbuckles.
- Tightened backstay enough to take the flop out of it. Had to leave the chainplate adjuster on it.

1) Does the tension sound about right? These were the readings off my Loos gauge for 5/32 wire.
2) Although I think the inners should be a bit less than the outers - any concerns with this amount of difference?

I finally tuned the rig on my M last week and she performed very well on the weekend. As I have to rig her each time I go sailing I tensioned the outer shrouds to 280lb. and the inner ones to 210lb.. Anything tighter makes it very difficult to pin the forestay down.(Can't adjust the turnbuckle after rigging as I use a roller furl)
The difference in tension actually resulted from the "requiered" mast bend.
She almost sails hands off now with a slight weather helm tacking at 20mph winds with or without jibe every time without problem.

So far I am very happy with my M except that I expected her to be a little faster under sail...but than, I also have my Honda just in case.

Hello:
I too have my uppers at 270~280, lowers around 220. When I had them tighter I couldn't get enough mast bend with the backstay to sufficiently flatten the sail. Also those flat spots in the hull caused by the chainplate tension got bigger and the tension did not increase in linear fashon (like overtightening and stretching a bolt).
On our recent San Juan trip the boat performed very well. When the winds lightened to 10 knots we were sailing faster than the 30' fin keel boat we were sailing with. It's true, I have video. Winds 12~14 we were at the same speed. Above 14 knots, he took off with a 1.5 knot advantage. He also had more mass which helped cut the waves when the seas got up.

I just purchased a used 26M from an individual who used it twice. I have been preticing raising the mast/sails/rigging but have no idea how to make sure I have the corect tension. I am using the roller furler and have the typical two port and starbort stays. From the preceeding posts, it looks like folks like 260-280 for the front stays and slightly less for the back stays. How do I measure this tension (a tool I assume) and does this tension really make a sailing difference or is it just technical jargon that doesn't really mean much to an Average sailor?

Regards

Rich
Bakersfield, Ca.

Rich,

Point of clarification - the tensions I was referring to are for the shrouds (port and starboard), not the stays (fore and aft.) My reason for adjusting mine "correctly" was more around stability/safety of the rig and less around sailing performance.

I measured shroud tension using a very simple gauge from Loos I bought from West Marine ("Tension Gauge For 3/32-5/32" wire - A-91 WM# 179358 Mfg# 91A Only $48.99 USD") Not sure if this will work for you as I don't know the wire used on the M. The X seems to have 5/32 for shrouds.

Just got our Loos Guage Fedex from SailNet yesterday. Was $35.69

Rich -

After playing around a lot, I too have wound up with my outer shrouds at 280, my inners are around 240 - using the same Loos gage described above.

The outer shrouds at 280 seems to be about the max I can use and still manually connect the headstay with the furled genny on it.

You want sufficient tension on the rig to keep it stiff, especially on our M's with no backstay - your shrouds are doing the work of the backstay for you. If the Shrouds are too tight, you'll have trouble raising the rig, and if they are too loose, you'll see the downwind shrouds go slack in heavier winds - this is BAD. When you tack, hit a big wave, or whatever with one side of the shrouds slack, you'll notice the mast can do some funky things, including ultimately bending or having stress fractures.

Varying the tension on the inner stays between 220-240 seems to give the recommended bend or flex in the mast to get proper sail shape, though I have had a very hard time getting my mast to be anything but ramrod straight.

Unfortunately, the owner's manual does a very poor job of describing how to tension the rig, and as far as I know MacGregor has never published any actual numbers for the rig tension settings.

- AndyS

Interesting that everyone specifies lbs of tension. Mine shrouds are all around 7-8% of the breaking strenth according to the loos 5/32 scale. I was trying for 10% but that seems like a lot. Didn't quite have the nerve and the lee side doesn't slack much in heavy winds.

I also split the backstay and I think what Don said is right. It restricts the mast bend. But on the other hand tht ay not be a bad thing. with a 12:1 purchase I've been told I can easily break or permenantly bend the mast.

What about temperature changes? I keep mine slipped year round with the mast up. I set my tension on typically warm afternoon. Will the steel wire contract and increase tension during the colder winter months?

Take nothing I say as words to live by as I am just getting into this topic - but to share my findings to date:

In terms of % of breaking strength - most reading I have done seemed to indicate 15% for outers, 10% for inners on a fractional rig.

I believe 5/32 wire has a breaking strength around 3300 lbs. (I have read "some 5/32 wire" does, but can't speak to the exact spec used by MacGregor.) That puts outer/inner tension at 500/330 lbs.

Based on a) the taughtness of my rig currently being only 360/240 lbs., and b) others indicating they are running under 300 - I don't think I need (or would want to) go any higher. My boat is slipped year round.

Dan B wrote:Take nothing I say as words to live by as I am just getting into this topic - but to share my findings to date:

In terms of % of breaking strength - most reading I have done seemed to indicate 15% for outers, 10% for inners on a fractional rig.

I believe 5/32 wire has a breaking strength around 3300 lbs. (I have read "some 5/32 wire" does, but can't speak to the exact spec used by MacGregor.) That puts outer/inner tension at 500/330 lbs.

Based on a) the taughtness of my rig currently being only 360/240 lbs., and b) others indicating they are running under 300 - I don't think I need (or would want to) go any higher. My boat is slipped year round.

I seriously doubt the deck can handle 15%. At 8% I've had comments from other Mac owners on howmuch tighter mine are then theirs. You might get 10%, but much more then that and I think something is going to go crack snaple pop.

Dan B wrote:Take nothing I say as words to live by as I am just getting into this topic - but to share my findings to date:

In terms of % of breaking strength - most reading I have done seemed to indicate 15% for outers, 10% for inners on a fractional rig.

I believe 5/32 wire has a breaking strength around 3300 lbs. (I have read "some 5/32 wire" does, but can't speak to the exact spec used by MacGregor.) That puts outer/inner tension at 500/330 lbs.

Based on a) the taughtness of my rig currently being only 360/240 lbs., and b) others indicating they are running under 300 - I don't think I need (or would want to) go any higher. My boat is slipped year round.

I seriously doubt the deck can handle 15%. At 8% I've had comments from other Mac owners on howmuch tighter mine are then theirs. You might get 10%, but much more then that and I think something is going to go snap crackle pop.

Who remembers Bruce Whitmore? Here is something fairly recent:

http://www.briontoss.com/wkstone/webkey ... &password=

Dave,
The link bombs out on me?
Any suggestions?

Rich

Dave wrote:What about temperature changes? I keep mine slipped year round with the mast up. I set my tension on typically warm afternoon. Will the steel wire contract and increase tension during the colder winter months?

Actually, other things being equal, the opposite. Yes, the steel will contract as it gets cold, but the aluminum in the mast has a higher thermal expansion coefficient, about 1 1/2 times that of steel. Since the mast is providing the stiffness in compression to conteract the shroud tension, in cold weather it will contract more than the shrouds, thus, the tension will be less in the winter. This would seem to be beneficial.

Of course, other things are not equal. The confounding factor is the boat itself. It is essentially polyester (plastic) with a thermal expansion coefficient about twice that of aluminum. On top of that, it's not a simple mechanical system like a wire in tension or the mast in compression, it's a complex composite structure with a bunch of different shapes, stiffening bulkheads, thick and thin sections, etcetera.

How the entire system of mast, standing rigging and the boat they're both attached to might behave in extreme temperatures is anybody's guess.

Also, quite seroiously, give the rest of us a break. In Orange County, CA, you're asking about winter to summer temperature extremes? There aren't any.

RichandLori wrote:Dave,
The link bombs out on me?
Any suggestions?

Rich

Sorry and yes...try going to www.briontoss.com

On the lower left, click on SparTalk

Once there, go down to the search box, type MacGregor 26X and push the search button

It should come back with a April/2004 question on rigging an X by Rich Nutting and a reply from Bruce Whitmore.