Akestor
Well-Known Member
my westerly 31 has 6mm (11 strand) diameter ringing except the wire that goes through furler which is 8mm. Thinking of replacing all rigging with 8mm. Is there anything wrong with that? mechanically speaking?
thicker standing rigging?
- Thread starter Akestor
- Start date
VicS
Well-Known Member
Using thicker wire is no problem as such but I would only tension it to the same figure as the original. If you tension it to the figure you would normally set it to for the thicker wire you could be setting it to a tension the boat is not designed for.
But why increase from 6 to 8 ? Need a stronger rig or just money to spend?
11 strand ? Is that right ?
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lw395
Well-Known Member
Thicker standing rigging can mean the leeward shroud goes completely slack too soon.
Probably not going to hurt a Westerly 31, but it's really just pointless weight aloft.
Probably not going to hurt a Westerly 31, but it's really just pointless weight aloft.
James_Calvert
Well-Known Member
All other things being equal, thicker rigging would be less stretchy than thinner, wouldn't it?
Certainly works that way for cordage.
Poignard
Well-Known Member
Thinking I knew better than the designer of my boat (Kim Holman), I replaced the 5mm shrouds specified on his drawings with 6mm.
I then found that the terminal eyes in the new shrouds were larger in diameter than the originals, and this meant that the clevis pins in the mast tangs were no longer a snug fit in the new eyes, as they had been in the old. I didn't like this.
I had to turn up some thin-walled s/s bushes to take up the slack.
Not a problem as I have a lathe, otherwise I would have had to pay someone to do it for me
I then found that the terminal eyes in the new shrouds were larger in diameter than the originals, and this meant that the clevis pins in the mast tangs were no longer a snug fit in the new eyes, as they had been in the old. I didn't like this.
I had to turn up some thin-walled s/s bushes to take up the slack.
Not a problem as I have a lathe, otherwise I would have had to pay someone to do it for me
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vyv_cox
Well-Known Member
Ultimately that is true but you only tension your rigging to around 20% of UTS. Sailing loads will add a bit but nowhere near enough to stretch the wire significantly.
Norman_E
Well-Known Member
If it was designed for 6mm wire. and has worked OK with it for many years, why change? If you fit thicker wire you cannot tension it to the same percentage without risking damage to chainplates and possibly distorting the boat so that things happen like cabin doors getting stuck.
Akestor
Well-Known Member
hi Vic you are right i got it wrong! actually it should be 1x19 strand wire continuous according to boat specs unless last rig replacement was set differently. I experienced some heavy weather with the meltemi in aegean sea. Had some strong "flaps" of the jenoa going downwind ( shaking rigging) and splashing into big waves going upwind. These sudden stresses at the rigging makes me think of the 8mm, but then i hadn't though of the tension factor.
I relize that know. It's like setting thick bass strings to a mandolin
Akestor
Well-Known Member
I ll stick to the 6mm. Stupid but didn't think of the foundamental factor of tension difference!
Norman_E
Well-Known Member
Good call to stay with the original design IMHO. I suggest that you get yourself a rig tension gauge. I use the largest size of Loos Professional gauge as my rigging is mostly 10mm, but the smaller one that reads wire sizes to 7mm will do for you because your 8mm forestay has its tension set by the backstay and is not measured directly. It is important that you keep your rig properly tensioned because a slack rig is more likely to fail than one kept properly tight.
Roberto
Well-Known Member
Also, safety factors are usually used to make the cable the weakest link: a lot "better" to break a cable and possibly dismast, than breaking open one third of the deck
mbroom
Well-Known Member
But why??
wilkinsonsails
Well-Known Member
You would definitely have a problem connecting new 8mm wire terminals to 6mm mast tangs and chainplates too.
Bigger wire, bigger eye and pin sizes .
Bigger wire, bigger eye and pin sizes .
Poignard
Well-Known Member
See post #5.
Akestor
Well-Known Member
indeed!
graham
Well-Known Member
Larger size clevis pins may not fit in the holes.I would change like for like if that was the original spec.
Red Panda
Well-Known Member
A previous owner "cleverly" changed the shrouds on my boat to 8mm instead of 6mm.
I suspect because he was able to get some cheap, rather than for any performance or engineering reason. He didn't bother changing the forestay or backstay, they're still 6mm!
It's a pain in the transom! I had to buy a very expensive rig tension gauge (>8mm = twice the price for the gauge), tuning guides aren't written for non-standard rigging, in fact this winter I'm going to swap it back to 6mm.
I suspect because he was able to get some cheap, rather than for any performance or engineering reason. He didn't bother changing the forestay or backstay, they're still 6mm!
It's a pain in the transom! I had to buy a very expensive rig tension gauge (>8mm = twice the price for the gauge), tuning guides aren't written for non-standard rigging, in fact this winter I'm going to swap it back to 6mm.
CAPTAIN FANTASTIC
Well-Known Member
The Westerly 31 and the majority of other boats have low tension rig; no need to increase the wire diameter; even if you were to replace the 6 mm with 5mm or even 4mm (hypothetically) it would make no difference.
