Backstay Tension

[Cattywampus]

Without a tension gauge, is there any way to know if the rig is tensioned too tight? My rig is way too loose, lots of headstay sag when going to weather. Just don't want to over do it when I tighten it up.

[Wand]

Originally Posted by Cattywampus

Without a tension gauge, is there any way to know if the rig is tensioned too tight? My rig is way too loose, lots of headstay sag when going to weather. Just don't want to over do it when I tighten it up.

Unless you're among a racing crowd, where all sorts of contrary theories flourish, the main purpose of the stays is of course to keep the stick pointing skyward on all points of sail. It's natural and okay for the leeward shrouds to be slack - they're not doing any work and I've never been able to see any harm in it, unlike a too tight rig that puts extra strain everywhere (remember Kookaburra, 1987!).

So, how much tighter should your backstay be? If it's doing it's job on a run, it's tight enough imo. But if you're still a bit uneasy, tighten it a little till the worry goes away. Others will contest this post but, for cruisers, I reckon there's stacks of latitude.

[capngeo]

I have a hyd backstay tensioner.... Only use it to unload the rig when in port. The previous owner was a racer and he installed all sorts of go-fast goodies... Me? I don't even bother to clean the bottom!

[Wand]

Originally Posted by At sea

...(remember Kookaburra, 1987!).

Ah, correction. It was oneAustralia that split and sank in Auckland in 1995 in the LV challenger series. Cranked in a little too hard and it folded...whoops

[Onesea]

I have played at racing and seen backstays abused.

Racing answer depends on conditions at time. Cruising answer when watch your boat and mast.

Racing some of the signs of to much back stay tension I have seen:
1. Door to owners cabin aft not opening when hull starts twisting.
2. You cannot pull any harder on the adjustment system.
3. The mast starts taking funny S shapes.
4. The seams on the wooden planks start opening up due to stresses.
5. Deck fittings starting to weep due to over loading.

With my boat I would not play those games.

Just remember depending on the design of the rig one wire effects another...

Adjusting the back stay (depending on the amount) you can:
A) bend the mast, changing the set of the main sail.
b) tension /slack your lower shrouds?
C) Increase fore stay tension (the plan?),
D) change the rake of the mast, may change the "feel" of the boat. To do this significantly you probably have to adjust the forestay (also worth considering?)

Remember some forestay sag should be cut into the sail. Sail makers know forestays sag.

Lots of tension on the main sheet can increase forestay tension.

Cruising what do I look for?
A moderate forestay tension.
A mast with a slight aft bend or straight depending on mast type.
Not to much slack in the rigging so the mast does not slop around in a sea way.
A moderate back stay tension,(I often climb onboard over the stern using the back stay as a support).

Do not just look at it in port, sight up the track in varying conditions and headings beating, reaching, running etc, it can change significantly.

All masts are designed to bend and move. When ever you are on another boat feel there rigging and compare.

I am sure some one will disagree with some of the above.

If the stick stays up and she is sailing ok, you have not got it far wrong!

[Pete7]

This from Selden is worth a read.

http://www.seldenmast.com/_download....=595-540-E.pdf


Pete

[swagman]

Originally Posted by At sea

Unless you're among a racing crowd, where all sorts of contrary theories flourish, the main purpose of the stays is of course to keep the stick pointing skyward on all points of sail.......... It's natural and okay for the leeward shrouds to be slack - they're not doing any work and I've never been able to see any harm in it, unlike a too tight rig that puts extra strain everywhere.........

Sorry - but its completely wrong to tell people there is no harm going to come to a leeward wire stay that is continually flexed as it flops around with no loading on it. The reverse is almost certainly true.

Most sailors will one day experience older wire unstranding at the point where it enters a swage or solid fitting. That breakage is invariably accelerated when the swage or fitting remaining stationery and the wire is flexed. Which is what happens when a leeward stay flops around.

Load up your rig tension correctly so that no stays flop back and forth, and you'll significantly reduce the risk of your wire failing.

Cheers
JOHN

[Wand]

Originally Posted by swagman

Sorry - but its completely wrong to tell people there is no harm going to come to a leeward wire stay that is continually flexed as it flops around with no loading on it. The reverse is almost certainly true.

Most sailors will one day experience older wire unstranding at the point where it enters a swage or solid fitting. That breakage is invariably accelerated when the swage or fitting remaining stationery and the wire is flexed. Which is what happens when a leeward stay flops around.

Load up your rig tension correctly so that no stays flop back and forth, and you'll significantly reduce the risk of your wire failing.

Cheers
JOHN

I knew that reply was coming sooner or later - that's why I said "others will contest this post"

It's true us boaties are an opinionated bunch but I'd suggest saying that your opinion is "different" rather than another poster's opinion is "completely wrong".

In this case, I have heard that theory, considered it and, on balance, decided to discount it. Others have gone through the same process and accepted it. It is one of those eternal club bar debating issues.

Unless you have some compulsive scientifically supported evidence with which to put the debate to rest, then I'd suggest that your position is just supposition - albeit not without fair (but contestable) reason. And even if that supposition is correct, then remember you must also consider the other implications of having the rig tight enough to prevent such leeward slack in conditions moderate and above.

It's best I reckon that we present our views and let the OP put it into the great melting pot of responses. That way at least the mystery of all things boating is not artifically simplified by the inference that there is a right and wrong answer to everything.

[delmarrey]

Are you sure its not the forestay that's too loose?

[s/v Jedi]

Originally Posted by At sea

It's true us boaties are an opinionated bunch but I'd suggest saying that your opinion is "different" rather than another poster's opinion is "completely wrong".

In this case, I have heard that theory, considered it and, on balance, decided to discount it. Others have gone through the same process and accepted it. It is one of those eternal club bar debating issues.

I'm sorry but don't agree with this at all. I have never met a rigger who states that slack leeward shrouds is okay. It isn't, and you will have to prove the world and her experts to be wrong before you can change accepted practice. There's the issue with shock loads that you probably also considered and dismissed as silly? A properly tensioned capshroud stretches the wire enough so that the leeward wire doesn't go slack and keeps the masthead in the same position as much as possible.

ciao!
Nick.

[boatman61]

Maybe just reset it...
Look up the line of the mast... eye close to the sail track... is it straight.. mark lowers shroud screws and then slacken...
Sight up mast again... is it still straight... if not slacken opposite shroud till corrected.... take in any slack on other side but not too taut...
Usually most boats I've owned have had rakes between 5 and 7.5 degrees... except the Wharrams... they had more...
Hang a weight on your topping lift and take a look.. if it looks about right slacken the back and tighten the forestay till hand tight... repin and tighten backstay till happy.... check uppers and retension lowers... checking mast line as you go..
You don't need them bar taut... a tad before is good.

[osirissail]

If you really want to find out what's what with rigging plus a lot more you probably don't want to know - get Brian Toss's
The Complete Rigger's Apprentice

Brion Toss Yacht Riggers, Sailboat Rigging::Books

It's all in there and he even sells videos showing you exactly how to examine and tune your rig.

[boatman61]

Originally Posted by osirissail

If you really want to find out what's what with rigging plus a lot more you probably don't want to know - get Brian Toss's
The Complete Rigger's Apprentice

Brion Toss Yacht Riggers, Sailboat Rigging::Books

It's all in there and he even sells videos showing you exactly how to examine and tune your rig.

Good one Osiris....
A link to a good site is 100% better than an unknowns advice...

[cabo_sailor]

You gentlemen probably know quite a bit more than I. I've always gone by the standard that the lee shrouds should be just a tiny bit loose in about 15kt on a beam reach. Not floppy but not piano strings either. If the roller furling was real difficult to operate, I considered tightening up the backstay or the forestay. The decision was based upon sighting up the mast and just how much tension I thought needed to be applied. A tiny bit? A couple turns on the backstay. Really loose, sight up the mast and if it looked like it was already being bent enough to be noticeable, then I would tighten the headstay. Totally confused? I would hire a rigger for an hour or two. I'm not a racer so extracting the last few millimeters of rig tension has not been a factor. Having said all this, I do notice some fellow sailors at my dock whose shrouds are actually floppy on both sides while tied to the dock. A conundrum, I disagree with that but what the hey it's their boat.

[cabo_sailor]

Originally Posted by osirissail

If you really want to find out what's what with rigging plus a lot more you probably don't want to know - get Brian Toss's
The Complete Rigger's Apprentice

Brion Toss Yacht Riggers, Sailboat Rigging::Books

It's all in there and he even sells videos showing you exactly how to examine and tune your rig.

Brian is a little bit proud of his products but I must admit I find them useful. I have his videos on knots, splicing, going aloft and rig tuning. Oh, I also have a copy of the riggers apprentice. If only I would stop lending them out and then having to buy another when I can't remember who walked off with the last one. Dang but these senior moments can get expensive.