Beginner questions: Rig Tension

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Rig Tension

Printed From: Yachts and Yachting Online
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Forum Name: Beginner questions
Forum Discription: Advice for those who are new to sailing
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Printed Date: 25 Jun 25 at 4:32pm
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Topic: Rig Tension

Posted By: ellistine
Subject: Rig Tension
Date Posted: 30 Apr 09 at 9:21am

I've heard lots of people mentioning that it's better to lower the rig tension in light winds.

What is it about a lower rig tension that helps?

Replies:

Posted By: Contender 541
Date Posted: 30 Apr 09 at 10:11am

In very light winds you want lower rig tension because it allows the rig to flex and 'catch' the wind rather than it hitting the sails and bouncing

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When you find a big kettle of crazy it's probably best not to stir it - Pointy Haired Boss

Crew on 505 8780

Posted By: JimC
Date Posted: 30 Apr 09 at 1:33pm

Originally posted by Contender 541

In very light winds you want lower rig tension because it allows the rig to flex and 'catch' the wind rather than it hitting the sails and bouncing

I don't know that I would go as far as saying that statement completely aligns with my (limited) understanding of the science involved...

To me the key thing about light airs is that the air movement is far more random and less predictable, and so the rig needs to be set up to cope with that. The air speed also varies far more betweem the bottom of the mast and the top. That in turn means that the adjustments like kicker and downhaul will generally need to be looser. Things like settings of rig tension and so on may well be a bit more class or rig specific, because there are subtleties... Therer are boats where its good to force some bend into the mast in light airs for instance.

Posted By: kanga
Date Posted: 30 Apr 09 at 1:39pm

It helps the slot of the mainsail and jib breathe better. You do not want it completly slack, else the energy from the wind goes in to pushing the mast, rather than filling the sails - but yes, slack in light winds. Some boats, in really heavy winds too, you slacking the rig tension so you have less mast rake too, which in turn depowers it.

Careful though, the boom is effectively lower when you do this, so its harder to get underneath it!

Posted By: desteve1
Date Posted: 30 Apr 09 at 3:34pm

when the sail is loose the sail can fill more (when there is too much wind you need to tighten the rig to help keep the boom in control)

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laser 81188 (looking for a name)

Posted By: Medway Maniac
Date Posted: 30 Apr 09 at 3:49pm

While I have paid lip service to the idea of lowering rig tension in light airs, I've never felt any benefit of it, and have always worried that I was, as Jim C says, missing out by losing my mast pre-bend.

What is absolutely for sure in most classes, you will lose out big-time if you don't pull the tension back on when the wind comes up.

I'd forget it and focus on kicker and sheet tensions, or lack of them.

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http://www.wilsoniansc.org.uk" rel="nofollow - Wilsonian SC
http://www.3000class.org.uk" rel="nofollow - 3000 Class

Posted By: ellistine
Date Posted: 30 Apr 09 at 4:16pm

Of course at the moment it's difficult to say if our rig is tight or loose anyway. Obviously there's a limit to how tight you can pull the rig on a plastic boat. It's possible that our 'tight' setting is still relatively loose. The rig does seem to shudder a fair amount when sailing in waves.

Might have to borrow me a tension gauge.

I'll beat them Laser 2000's yet!

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Posted By: Medway Maniac
Date Posted: 30 Apr 09 at 4:29pm

I note that the Vago rigging manual

http://lasersailing.com/downloads/boat-manuals/Vago.pdf - http://lasersailing.com/downloads/boat-manuals/Vago.pdf

says you should not exceed 70kg on the shrouds - that's jaw-droppingly low.

But you should beat the 2k's in light airs when your better sail area/wetted area ratio will help (if you use the XD rig). After that, the trapeze will help. The most significant performance factor in Vagos seems to be (we 3000's have shared a few events with them) sitting really far forward, and i mean really uncomfortably far forward anytime your not trapezing or planing - the transom drags hugely otherwise. Probably due to the boat weighting a lot more than designer Jo Richards reckoned with.

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http://www.wilsoniansc.org.uk" rel="nofollow - Wilsonian SC
http://www.3000class.org.uk" rel="nofollow - 3000 Class

Posted By: ellistine
Date Posted: 30 Apr 09 at 5:07pm

Originally posted by Medway Maniac

I note that the Vago rigging
manual

http://lasersailing.com/downloads/boat-
manuals/Vago.pdf - http://lasersailing.com/downloads/boat-
manuals/Vago.pdf

says you should not exceed 70kg on the shrouds -
that's jaw-droppingly low.

But you should beat the 2k's in light airs when your
better sail area/wetted area ratio will help (if you use
the XD rig). After that, the trapeze will help. The most
significant performance factor in Vagos seems to be (we
3000's have shared a few events with them) sitting
really far forward, and i mean really uncomfortably far
forward anytime your not trapezing or planing - the
transom drags hugely otherwise. Probably due to the boat
weighting a lot more than designer Jo Richards reckoned
with.

Yes. The wife and I have had a lot of 'cosy' time lately
with me sat where she should sit and her hugging the
mast. At least you can audibly tell when you're forward
enough with the amount of gurgling that comes from the
rear if you're not.

Did you do the Rutland 2k, Vago, 3k, 5k event last year?
That was our first ever race. Nearly enough to put us
off racing for life!

I think I can forget about the rig tension.

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Posted By: Medway Maniac
Date Posted: 30 Apr 09 at 5:22pm

Originally posted by ellistine

Did you do the Rutland 2k, Vago, 3k, 5k event last year?
That was our first ever race. Nearly enough to put us
off racing for life!

I think I can forget about the rig tension.

We sailed at Rutland, but last September at our Nats . Will you be at Grafham in June? Our Nats again.

Looking at the rig tensioning arrangement on the Vago, i'd guess just pull on as much as you can comfortably by hand (no crew hanging off the forestay or whatever) and that should do.

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http://www.wilsoniansc.org.uk" rel="nofollow - Wilsonian SC
http://www.3000class.org.uk" rel="nofollow - 3000 Class

Posted By: ellistine
Date Posted: 30 Apr 09 at 7:37pm

Originally posted by Medway Maniac

We sailed at Rutland, but last
September at our Nats . Will you be at Grafham in June?
Our Nats again.

Actually, you're right, it was 2000's, 4000's and 5000's
at Rutland. Soooo windy it was unreal. I think out of
the six races we managed to start three and finish one.

I don't think we'll be doing Grafham this year due to a
date conflict but next year we hope to do most of the
Vago events so I'll be looking out for you as you steam
past!

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Posted By: redback
Date Posted: 09 May 09 at 4:39pm

The way I see it you need enough rig tension that the mast stays as bent as you require up to a wind strength that you can handle. Above that wind strength you want the mast to bend more. The amount of tension controls (amongst other things) when this change-over occurs. If you have too little rig tension this change occurs before you are fully powered. If you have a very flexible boat - such as my old plastic Enterprise - it is noticeable that you can't get enough rig tension to maintain control of the mast in strong winds. My 4000 on the other hand is very stiff and the rig remains stable in very high winds and hence the other controls such as downhaul and kicker are very good at depowering it without drama.

I'm talking about light winds and strong winds ie when under-powered and over-powered. There is a third wind strength called a drifter where sensible people retire to the bar, but if you do get caught out you'll find it really doesn't matter what what rig tension you use. Much better to make sure you catch the puffs.