Rig tension.

[IanCC]

30' masthead sloop rig tension. 2021 rigging.

I have read the books, done the 2 metre tape thing. But then after a few months it's not as tight as it once was. So, do i slack it all off and start again with the 2 metre tape, but now with pre stretched wire, or what? . The books are silent on this.

Thanks for all input.

 

[dunedin]

Personally I have no idea what the “2 metre tape thing is”. But unless I was racing (in which case use proper tension guage and boat specific tuning guide) I just have a heave at the shrouds to assess tension. Get them pretty tight by feel (half inch or so movement), then go sailing in a bit of a breeze, sheet in tight and check the lee side doesn’t go too slack. Not too much science.

 

[IanCC]

Personally I have no idea what the “2 metre tape thing is”. But unless I was racing (in which case use proper tension guage and boat specific tuning guide) I just have a heave at the shrouds to assess tension. Get them pretty tight by feel (half inch or so movement), then go sailing in a bit of a breeze, sheet in tight and check the lee side doesn’t go too slack. Not too much science.

Fair enough.

 

[johnalison]

With modern double-spreader rigs on larger boats I think that correct setting-up is necessary for the safety of the rig as well as optimum performance. With smaller boats and simpler rigs this may not be absolutely necessary. On my Sadler 29 with its masthead rig I would just tighten it until it felt right and then check on each tack when sailing, but I accept that this does not reach what would be considered ideal. If the rig is slack after a short time, either the wire is stretching or the boat going out of shape. On my current boat the rigging was checked by a rigger after a few months and has had hardly any adjustment after many years.

 

[coveman]

Selden do a useful guide for all rigging types that may be helpful - google "selden hints and advice".

 

[VicS]

Personally I have no idea what the “2 metre tape thing is”. But unless I was racing (in which case use proper tension guage and boat specific tuning guide) I just have a heave at the shrouds to assess tension. Get them pretty tight by feel (half inch or so movement), then go sailing in a bit of a breeze, sheet in tight and check the lee side doesn’t go too slack. Not too much science.

Then see the Selden Hints and Advice pdf mentioned by Coveman. It is described in there as the "folding rule method".
They also describe how to check in the way you describe but with a little more precision, ie at a 20 degree angle of heel.

 

[dunedin]

Then see the Selden Hints and Advice pdf mentioned by Coveman. It is described in there as the "folding rule method".
They also describe how to check in the way you describe but with a little more precision, ie at a 20 degree angle of heel.

But my point was you probably don't need that much precision for a cruising 30 footer. I haven't needed that in a quarter of a century sailing - and we still overtake most boats of similar size upwind, unless they have black sails.

 

[bignick]

The intention of the “folding rule method” is to be able to set a known tension in the wire, without having a tension gauge.
You still want the original intended tension, for the sake of the rig, so if you aren’t able to borrow a gauge then just start over again.

 

[Daydream believer]

Another point about correct tension, with double spreader fractional rigs, is that one has to set up with a degree of pre bend, to avoid mast inversion. This could be catastrophic. Just setting up to avoid a bit of slack leaward shrouds up wind, is not really sufficient. There is a correct balance between each set of shrouds. Giving them a "twang" is not the way forward. Personally, I feel that- for the cost involved- a rig tension guage is an investment, which will last years.

 

[Bobc]

Has your rig stretched, or has your boat bent?

 

[Chiara’s slave]

Has your rig stretched, or has your boat bent?

Ours needed adjustment a few months after renewal. That is the diamond stays, we have, and regularly use, a tension gauge. The diamonds are where our pre bend is controlled. As DDB says, modern fractional rigs all work like that, ours being a tri is no different in principle. The rest of our rig is tensioned with the running backstays according to wind strength, simple with dedicated winches.

 

[Bobc]

Ours needed adjustment a few months after renewal. That is the diamond stays, we have, and regularly use, a tension gauge. The diamonds are where our pre bend is controlled. As DDB says, modern fractional rigs all work like that, ours being a tri is no different in principle. The rest of our rig is tensioned with the running backstays according to wind strength, simple with dedicated winches.

Yes, but we're not talkjng about your rig, we're talking about a simple masthead rig, which shouldn't need re-tensioning.

 

[Chiara’s slave]

Yes, but we're not talkjng about your rig, we're talking about a simple masthead rig, which shouldn't need re-tensioning.

It plainly does. I'd start again with the same method. Why you think not taking up the stretch is a good idea is beyond me.

 

[Bobc]

It plainly does. I'd start again with the same method. Why you think not taking up the stretch is a good idea is beyond me.

It shouldn't be tight enough to stretch, but quite often if the rig has been over-tightened on an old boat, the boat will bend, making the rig slack. If you just re-tighten the rig, the boat just bens more, until you do some proper damage.

The wires on a simple masthead rig are simply there to keep the mast in column. There is no pre-bend, and the backstay simply tensions the forestay.

 

[Chiara’s slave]

It shouldn't be tight enough to stretch, but quite often if the rig has been over-tightened on an old boat, the boat will bend, making the rig slack. If you just re-tighten the rig, the boat just bens more, until you do some proper damage.

The wires on a simple masthead rig are simply there to keep the mast in column. There is no pre-bend, and the backstay simply tensions the forestay.

Er, yes. And if the rig is slack, a deck stepped mast can jump off it’s step, and a keel stepped mast can over stress the deckwhere it passes through. Correct tension, not over tension, is the purpose of owning a gauge.

 

[Bobc]

One other thing for the OP to consider, is that every time you physically stretch stainless, you weaken it.

 

[Chiara’s slave]

One other thing for the OP to consider, is that every time you physically stretch stainless, you weaken it.

The correct tension won’t result in extra stretch. If he’s winding it on too hard, possibly. But again, a gauge will tell you that.

 

[fredrussell]

Apologies for going a little off topic, but my mate has just had the standing rigging done on his 31ft double spreader rig. All work done by a well regarded rigger. I was surprised to find that his intermediates are pretty loose. I would estimate you could deflect them an inch each way without any great pressure (with your little finger, say). I’ve always thought they should be tight enough to only show slackness slightly when hard on the wind in a good breeze. That’s how mine are anyway.

 

[Bobc]

The correct tension won’t result in extra stretch. If he’s winding it on too hard, possibly. But again, a gauge will tell you that.

But if it's gone slack and the boat isn't bending, that suggests that it's been over-tightened and stretched.

 

[Chiara’s slave]

But if it's gone slack and the boat isn't bending, that suggests that it's been over-tightened and stretched.

No it does not. It suggests it’s new, and the stretch is normal. If your boat is that floppy it’s probably time to take a chainsaw to it.