Rig tension

groundhogyh · Jul 12, 2006

I was wondering about that too.
I remember when racing on a Kirby25, we found some rig tension specs. They seemed quite tight, but after tightening the rig, we were able to point much higher. brbr

Is there a gadget that you can put on your rig where you can apply heavy tension just before you go out, and then release it when you are done sailing? Seems to me this would minimise the enormous compression forces on the roof.

groundhog

peterjmaud · Jul 12, 2006

I do believe that there is a piece of equipment that is used for
measuring rig tension. If you go back into history a little way the
cable tensiometer was developed to insure that the correct tension
was applied to the cables that were attached between the upper and
lower wings of the early biplanes. Evidently either too tight or too
slack could result in wing failure. In the field of exercise testing
they were used a lot 30 to 50 years ago for measuring strength. I
still have an old one in my office but the trouble is that you need
to know the conversion factor for the specific diameter of the cable
and the sheet indicating that is currently missing. I had tried to
get some figures for the tension for rigging on my Rhodes 22 a few
years ago but nobody seemed interested. Theoretically I think your
suggestion seems quite sound.
Peter

At 02:27 PM 7/12/2006, you wrote:

SVFlyAway · Jul 12, 2006

The device is the Loos Tension Gauge. They come in two or three sizes and
cost under $100 US for the smaller sizes which would be used for the Vega.
We used them all the time when we were racing, but still did a little hand
tweaking when we were finished. You can find them on the internet.

Most sold in the US have the wire size scale in inches, in other countries
it is in metric. There is no difference in the gauge; it is only in the
table of values used to calculate the tension from the reading (if that
makes sense). I was able to get the metric table for my US scale when I went
to a European boat once, so I didn't have to buy another gauge.

SVFlyAway · Jul 12, 2006

I should have mentioned this in my earlier mail about the Loos gauge.

What we used to do was to get the boat all tuned up to our liking by doing a
lot of sailing and letting experience guide us when it was just right. Then
we'd measure the tension and note it on paper. When we needed to retension
the rig, after some change or work, we'd take it back to our previous
readings, sometimes we'd still tweak it a bit (racers are fanatics). Of
course this assumes that the rig has the initial "stretch" out of it. Even
wire rope will change a very little bit under load, not much, but when I was
a diehard racer I thought it all meant something.

As for the leeward rigging loosening, that is very common as there is always
some give. You probably don't want the rig so tight that there is no give,
as that would put a overdo strain on all the fittings. But then it probably
shouldn't be so loose so the shrouds to flap in the breeze. Probably the
best indicator is how the mast looks under the press of a medium breeze. Go
forward and sight up the stick and see how far it is falling off. The amount
is dependent on the boat. Maybe some of the longtime Vega owners have a
better feel for this on the Vega than I do.

_____

From: AlbinVega@yahoogroups.com [mailto:AlbinVega@yahoogroups.com] On Behalf
Of Chris Brown
Sent: Wednesday, July 12, 2006 4:07 PM
To: AlbinVega@yahoogroups.com
Subject: RE: [AlbinVega] Rig tension

The device is the Loos Tension Gauge. They come in two or three sizes and
cost under $100 US for the smaller sizes which would be used for the Vega.
We used them all the time when we were racing, but still did a little hand
tweaking when we were finished. You can find them on the internet.

Most sold in the US have the wire size scale in inches, in other countries
it is in metric. There is no difference in the gauge; it is only in the
table of values used to calculate the tension from the reading (if that
makes sense). I was able to get the metric table for my US scale when I went
to a European boat once, so I didn't have to buy another gauge.

mrkk1103 · Feb 23, 2013

Hi folks,
I'm sure you've covered this in detail in the past but wondered if some of you would advise me. I've just had my mast put back up after the winter and would like to know how tight the rig should be. I've seen comments that suggest that we need to be careful with the tension on our Vegas because of the way the mast Is supported. Do you de-tension your rig after each use or do you keep it fairly loose all the time? What does tight or loose feel like? At this stage I'm more interested in looking after my boat than getting the maximum speed out of her. All words of wisdom gratefully received.
Thanks,
Mark

pjacobs55 · Feb 23, 2013

Hi Mark,
Before tensioning the rig it's best to make sure the mast is being supported properly by the mast beam. There'a a ton of info on this here on the forum.

Page 13 of The Vega Handbook says:
"Tuning the boat means, amongst other things, that the shrouds and stays have to be tightened correctly.
The forestay, permanent back stay, cap shrouds and forward lower shrouds be tightened hard.
The aft lower shrouds require only light tightening
thus making the mast bend forward a little in the middle to make the mainsail flatter
in strong winds."

That said, I keep all my shrouds about even in tension: not too tight with only a bit of slack showing on the leeward shrouds when on a brisk beat.

Hope this helps,
Peter
www.sintacha.com

mrkk1103 · Mar 1, 2013

Hi Peter,
Sorry about the slow delay but thank you for your thoughts. I don't think I've quite got the hang of searching the forum successfully yet but I'll spend some more time seeing what other people have said.
Cheers,
Mark

Vega1447 · Mar 3, 2013

There might be a tuning guide that gives tension settings using a LOOS
gauge.
Certainly you'll want to see that the leeward shrouds get soft when the
boat is heeling over with the leeward rail in the water, otherwise you
would have too much tension.
A few hours with a reputable rigger or sail maker would get the rig right.
Good luck,
Pete

mrkk1103 · Mar 3, 2013

Thanks for that. What triggered this question was items that I've read describing the damage that some Vegas have had where the mast is supported on the beam in the cabin because the rigging was too tight. I'm definitely in favour of longevity over performance but then presumably if everything is flapping about more than it should other damage can happen. There are a couple of other Vegas in Chichester harbour where I'm now based, I'll have to see if I can have a look and a compare. Being a newbie I don't really know what too tight or too loose feels like. As you say some way of measuring may be helpful and have a chat with the chap who rigged the boat.

dougpol1 · Mar 3, 2013

Pete, I mostly agree with you on tightness of shrouds. But I would say
that a modern sail maker may want to tighten the rigging too tight.
Don't forget the boat was designed in the mid 60's when rigs were more
loose than today when more modern boats are build to stand the mast
load. Don't forget the sail maker wants his sails to be faster so he
cranks down on the rigging. He likely knows little about the strengths
and weaknesses of a Vega. I think this is the reason some have had a
problem with the beam under the mast sagging. Also lower shrouds pulling
at the wider angle pull inward on the hull and possibley have a tendancy
to jack up the cabin top on both sides causing it to lift off of the
bulkhead on either side of the mast. I have no proof of any of this but
this is my suspicion as to what causes the problem on some Vegas. My
sugestion is to race, tight up the rigging to a predetermined tightness
and back off the turn buckles to a certain looseness when setting at the
dock or cruising. This is what we used to do on wooden boats in the
1950's. Of course we had a different problem then when the shrouds
pulling down on the mast pushed the keel dawn and opened the bottom
seams of the boat. In the sense that the mast is held up by a wooden
beam Vega seems to me more related to wood boats than modern glass ones
of today. Doug

stevebirch2002 · Mar 3, 2013

Hi All

there is a great article on Vega Rig Tension and setting in the latest VAGB
Newsletter. Go to www.albinvega.co.uk and download vagb51

Food for thought

Steve B

dougpol1 · Mar 3, 2013

That is a good article Steve, I printed it out to put in my Vega
manual. Thanks Doug

winslowbuoy · Mar 9, 2013

Hi Mark - If you are using the normal screwdriver through the centre of the bottle screw to tighten your shrouds and stays it is extremely unlikely that you would overtighten them.
I am not sure about Peter's advice on the lee shrouds going soft when hard pressedI suppose it depends on how soft.

Many of us have strengthened the beam under the mast with a kit from Steve Birch. The acid test is can you still operate the toilet door when the rig is tightened down if it binds then you probably need to support the beam.

Mike

gurkin42 · Mar 9, 2013

My concern with the addition of the main athwart ships support as utilised by Matt Rutherford and others is that it introduces a hard point that was not in the original design. The consequences of which seems to be further damage to that area of the deck head. It would be interesting to find out how many Vegas were altered in this fashion and then sailed offshore. I think it would be a good fix for a boat which sails around the cans but I am not certain that it is the best solution and I am interested to hear what people think. A common enough error these days is to over tighten the shrouds which as always comes from the racing crowd. I have to admit I go by feel which isn't very scientific and I detention my shrouds a little during winter haul out as I leave the mast up. I am sure that someone has a better answer. Cheers John

mrkk1103 · Mar 10, 2013

Hi MIke,
Thanks for that advice. That all makes sense. I think a combination of the article Steve pointed me too and your comments should see me right. Perhaps I was getting a bit too worried about the issue.
Cheers,
Mark