Rig Tension for 1979 Hunter 37C

[zached1]

I just bought a 1979 Hunter 37' Cutter. However, it is rigged as a sloop right now. I am going to buy the Loos rig tension gauge. It was hauled and the bottom painted and as of now all the rigging is loose. What should the tension be on each of the shrouds and stays when I go to tune the rigging? The boat did not come with a manual but i found one for a 1984. However, it does not say much about the rigging. Thank you.

 

[ggrizzard]

I'm not sure a "Spec" came with our boats.
Usually a local rigger will be the judge and advise me.

 

[Ed Schenck]

Two thoughts, only thoughts because I have never seen specific numbers for our H37Cs. One is to use the numbers on the Loos gauge. It provides suggested values for the different wire sizes right on the gauge. Or what I do which is get the mast in column and rake with very snug shrouds, forestay, and backstay. Then go sailing in a light breeze and from tack to tack remove any slack from the leward wires. Be sure to take the same turns on each wire of a side. Back at the dock check to see that the mast rake(a plumb on the halyard pulled to the top of the mast should intersect the centerline about six inches or more behind the mast). There is also mast bend to consider but I have never gotten that right.

 

[zached1]

Thank you, Ed. That will probably be what I do. I was going to aim for a rake of 6" and 20% on the upper shrouds. I had read somewhere about 15% on the lowers. I wanted to do it myself instead of paying a rigger to come out.

 

[Ed Schenck]

If I raced I would pay a rigger at least once to see what he/she could do. But this has served me well since 1999.

 

[Johnb]

My rigging was last tuned when it was replaced about 10 years ago. When I had the sails subsequently replaced a very highly respected came to the boat and spent some time with us including commenting on the rig tuning. One of the things he advised us to do is to sight up the sail track under various condition and confirm that the mast is staying in column at least from side to side. He also pulled and had me pull (horizontally) on the various shrouds whilst sighting along the sail track and declared the tuning to be good.

It seems that our rig is about as good as I will ever get it, so I have been thinking I might buy a gauge and measure it all and have the values for future reference. (and I will be happy to share)

We have 1/4" rigging. Should I buy a Loos PT2 or a Loos PT3?

 

[shemandr]

I hope I am not repeating myself but rig tuning is much more about the length of the standing rigging than the tension on the wires. You set the mast rake by adjusting the forestay length. The mast is set athwartships by the lengths of the shrouds - adjusted by the turnbuckles. Once centered with the correct rake the rig can be tightened. Somewhere in the 20% of the strength of the wire diameter.
It is also somewhat of a misconception that the tighter the rig the better. At some point, and it's not as much as we think, tightening the rig further just bends the boat. You can tell with you Loos gauge because further tightening doesn't produce higher tension or at least not in proportion to the tightening.

 

[Ed Schenck]

The shrouds are 1/4" but the backstay and forestay(maybe) are 9/32". I say maybe because my boat originally had a solid-rod furler. It now has a new furler over a 9/32" forestay.

 

[RoyS]

Mast rake, in my opinion, should be set by observing the boats response to a gust while sailing upwind. If the boat turns into the wind (rounds up) uncontrollably during a gust then remove rake. If, on the other hand, the boat appears to heel too much in a gust then increase the mast rake. My 1980 H33 responded well to mast rake adjustments to reduce a tendency to rounding up. You should eventually find the right rake adjustment for your boat by trial and error.

 

[rardiH36]

Entering the discussion a little late. But embedded here and attached are:

1) A pdf of very simple mast tuning procedure by Kemp Sails that is applicable to our boats and which I have found most useful.

2) A link to Seldon's mast tuning tutorial. In particular, take note of Seldon's "folding rule method" to achieve proper tension. Loos gauge not required.

http://www.seldenmast.com/files/1416926327/595-540-E.pdf

 

[zached1]

Thank you, Rardi. That should save some money on the gauge.

 

[joe28532]

I realize this is an older thread but incase you still need the tension spec or need it in the future Hunter says 20% of the wires breaking strength. Check out the link. http://www.marlow-hunter.com/wp-con...rt/Miscellaneous/Standing rigging tension.pdf

 

[jviss]

We have 1/4" rigging. Should I buy a Loos PT2 or a Loos PT3?

If it's all 1/4" you can use the model 90, PT-2, or PT-3.