Has anyone bought a rig tension gauge or have a link to a decent one at a reasonable price. It appears that you can buy one for testing on land for about $79 but the marine ones seem to cost $200+. Any comments as to their usefulness would also be appreciated.

Sorry I can't comment on the "onshore" vs marine ones, but I would guess that as for other items printing "marine" on the packet costs about $150 or so.

The Compass yacht group owns one and shares it around the members. Since you only need it for one day a year or so, buying with a few mates is a great idea.

Cheers, Graeme

Is this any help.

www.riggingandsails.com/pdf/selden-tuning.pdf

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Lazzz said..
Is this any help.

www.riggingandsails.com/pdf/selden-tuning.pdf

Yes thank you very much :-)

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wongaga said..
Sorry I can't comment on the "onshore" vs marine ones, but I would guess that as for other items printing "marine" on the packet costs about $150 or so.

The Compass yacht group owns one and shares it around the members. Since you only need it for one day a year or so, buying with a few mates is a great idea.

Cheers, Graeme

Thanks

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julesmoto said..
Any comments as to their usefulness would also be appreciated.

When I got my boat from the PO the rigging was quite loose (very surprising as he was an avid racer). I was quite nervous as I tightened things up while using the Loos, waiting for an ear-splitting "SPROING", but nothing broke and the improvement upwind was dramatic.
WIthout the gauge I would have chickened out way under the recommended 15% or so of MBS.

What type of boat.
Northshore 38 I think.
Pretty easy.
Set the forestay first. So 750 mm of rake at the tip
Then Caps to firm with a small not long handle spanner
You will feel when the load starts to come on.
Go for a sail, and the lowers will needs setting to match the luff round.
Do up the leeward one first and then tack
Tension on lower will generally need to match luff round ie no overbend creases.
Just keep sighting the mast track to keep it all straight.
You will never get it perfect as there will too many flaws in the mast section

Why are you trying to find out your rig tension? To tweak sail shape?

Several years ago, I bought 3 different sizes of loo's gauges from the UK for the price I would have paid for one in aus.
I wasn't interested in hearing stuff like tight but not too tight

Also, it would be highly unlikely you will ever get the shrouds too tight ona production boat like a Northshore 38, the boat will have bent long before then.

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lydia said..
Also, it would be highly unlikely you will ever get the shrouds too tight ona production boat like a Northshore 38, the boat will have bent long before then.

That's where the gauge will instantly show you that the effort for tensioning is not going to the wire because something else is giving

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Chris 249 said..
Why are you trying to find out your rig tension? To tweak sail shape?

From other NorthShore 38s that I viewed before I bought this one I noticed that the shrouds were extremely tight on mine. I don't want to bend the boat but it is probably already too late. At least it's an old boat so the fibreglass is fully cured. The rig was redone in 2018 and I found out by a chance encounter with someone else at a pier that this was because the rig went over the side while the boat was at its mooring in a storm in 2018. Apparently this was due to the rig and particularly the forestay being loose which allowed it to whip and snap out of the bow fitting. I'm wondering if as an overcompensating knee-jerk reaction the rig is now way over tight.

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lydia said..
What type of boat.
Northshore 38 I think.
Pretty easy.
Set the forestay first. So 750 mm of rake at the tip
Then Caps to firm with a small not long handle spanner
You will feel when the load starts to come on.
Go for a sail, and the lowers will needs setting to match the luff round.
Do up the leeward one first and then tack
Tension on lower will generally need to match luff round ie no overbend creases.
Just keep sighting the mast track to keep it all straight.
You will never get it perfect as there will too many flaws in the mast section

Wow thanks for that. I'm assuming that you have owned or raced one. How do you set the rake? Exceptionally long plumb bob on Main halyard and very calm day? Going to get new sails so might have to see if there is weather or lee helm with them before deciding on rake.

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lydia said..
Also, it would be highly unlikely you will ever get the shrouds too tight ona production boat like a Northshore 38, the boat will have bent long before then.

That's precisely what I'm afraid of. The shrouds are the tightest I ever felt. Deck stepped mast by the way

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julesmoto said..

Chris 249 said..
Why are you trying to find out your rig tension? To tweak sail shape?

From other NorthShore 38s that I viewed before I bought this one I noticed that the shrouds were extremely tight on mine. I don't want to bend the boat but it is probably already too late. At least it's an old boat so the fibreglass is fully cured. The rig was redone in 2018 and I found out by a chance encounter with someone else at a pier that this was because the rig went over the side while the boat was at its mooring in a storm in 2018. Apparently this was due to the rig and particularly the forestay being loose which allowed it to whip and snap out of the bow fitting. I'm wondering if as an overcompensating knee-jerk reaction the rig is now way over tight.

They need to be tight. As long as you can open doors etc they are not too tight. Tight rigging will help alleviate wear at the mooring.

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julesmoto said..

lydia said..
What type of boat.
Northshore 38 I think.
Pretty easy.
Set the forestay first. So 750 mm of rake at the tip
Then Caps to firm with a small not long handle spanner
You will feel when the load starts to come on.
Go for a sail, and the lowers will needs setting to match the luff round.
Do up the leeward one first and then tack
Tension on lower will generally need to match luff round ie no overbend creases.
Just keep sighting the mast track to keep it all straight.
You will never get it perfect as there will too many flaws in the mast section

Wow thanks for that. I'm assuming that you have owned or raced one. How do you set the rake? Exceptionally long plumb bob on Main halyard and very calm day? Going to get new sails so might have to see if there is weather or lee helm with them before deciding on rake.

Pardon me if I'm telling you suck eggs, but if you're going to get new sails then the sailmaker should be able to give you some pretty good hints. IMHO helm balance on a moderately modern boat, especially one as well known as the NS38, isn't much to do with mast rake. On a fractional rig, a few inches of twist or traveller will affect helm more than rake. They tend to have pretty vertical masts; I've only seen one with much rake (maybe 900mm??????) and it was quite noticeably different from the norm.

One of the critical things in rig tune on a fractional can't be done on the dock. What you're basically trying to do, generally, is to balance the increase in forestay tension (which affects jib depth) with the increase in backstay tension as you flatten the main. When the boat is set up right, the forestay sag is reduced enough that the jib reaches its proper top-end depth just as the backstay tension is increased to the stage where the mainsail matches its luff curve (as noted above) and is therefore about as flat as it will go.

So a lot of the time, you really need to know how deep your headsails should be at the top of their range, and them measure them (by taking a pic from underneath and measuring the draft on the pic) and ensure that they are getting optimum flatness as the mast bend reaches about the same amount as the mainsail's luff curve. If the headsail is too deep, wind more backstay on (or more shrouds) and if it's too shallow, ease.

If I recall correctly on my boat (same sort of speed, size and general design as a NS38 and with a fractional rig but a much stiffer top section) tightening the forestay by about 30mm took about 7% of draft out of the jib at the top of the wind range. Then of course you have to try to ensure that with the backstay eased so that the mainsail is powered up in light airs, the forestay sags enough to power up the headsail to the right depth.

The issue with the NS38 is the very long topmast and the single spreaders, which mean that you haven't got as much bend control as a boat with double spreaders, jumpers, etc.

With a boat as popular as the NS38 I'd expect a good sailmaker to be able to give you some pretty reliable draft percentages to aim at for the new sails.

On this topic of RIG tension. My boat has Selden, and their manual suggests tensioning the rig using a two foot rule, and measuring the stretch. Based on the rule 1mm equals 10 percent breaking strain on 1/19 stainless. I re-tensioned to these values based on my double swept back 9/10th rig.
should I bother with a loos gauge?

I did this about 3 years ago and have sailed about 3000 Mike's since, and tensions are still great!
cheers Richard

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Ramona said..

julesmoto said..

Chris 249 said..
Why are you trying to find out your rig tension? To tweak sail shape?

From other NorthShore 38s that I viewed before I bought this one I noticed that the shrouds were extremely tight on mine. I don't want to bend the boat but it is probably already too late. At least it's an old boat so the fibreglass is fully cured. The rig was redone in 2018 and I found out by a chance encounter with someone else at a pier that this was because the rig went over the side while the boat was at its mooring in a storm in 2018. Apparently this was due to the rig and particularly the forestay being loose which allowed it to whip and snap out of the bow fitting. I'm wondering if as an overcompensating knee-jerk reaction the rig is now way over tight.

They need to be tight. As long as you can open doors etc they are not too tight. Tight rigging will help alleviate wear at the mooring.

Thanks for that. I hadnt put two and two together before but the sliding fore- aft head door is bowed so that the finger pull which sits about 4 mil proud binds and additionally the door to the front v birth doesn't close easily without binding. I previously put this down to it being an old boat and simply due to timber in 32 years of moist marine environment. Now I am a bit worried and want to get a tension gauge even more when I finally get back to the boat after Lockdown.

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Chris 249 said..

julesmoto said..

lydia said..
What type of boat.
Northshore 38 I think.
Pretty easy.
Set the forestay first. So 750 mm of rake at the tip
Then Caps to firm with a small not long handle spanner
You will feel when the load starts to come on.
Go for a sail, and the lowers will needs setting to match the luff round.
Do up the leeward one first and then tack
Tension on lower will generally need to match luff round ie no overbend creases.
Just keep sighting the mast track to keep it all straight.
You will never get it perfect as there will too many flaws in the mast section

Wow thanks for that. I'm assuming that you have owned or raced one. How do you set the rake? Exceptionally long plumb bob on Main halyard and very calm day? Going to get new sails so might have to see if there is weather or lee helm with them before deciding on rake.

Pardon me if I'm telling you suck eggs, but if you're going to get new sails then the sailmaker should be able to give you some pretty good hints. IMHO helm balance on a moderately modern boat, especially one as well known as the NS38, isn't much to do with mast rake. On a fractional rig, a few inches of twist or traveller will affect helm more than rake. They tend to have pretty vertical masts; I've only seen one with much rake (maybe 900mm??????) and it was quite noticeably different from the norm.

One of the critical things in rig tune on a fractional can't be done on the dock. What you're basically trying to do, generally, is to balance the increase in forestay tension (which affects jib depth) with the increase in backstay tension as you flatten the main. When the boat is set up right, the forestay sag is reduced enough that the jib reaches its proper top-end depth just as the backstay tension is increased to the stage where the mainsail matches its luff curve (as noted above) and is therefore about as flat as it will go.

So a lot of the time, you really need to know how deep your headsails should be at the top of their range, and them measure them (by taking a pic from underneath and measuring the draft on the pic) and ensure that they are getting optimum flatness as the mast bend reaches about the same amount as the mainsail's luff curve. If the headsail is too deep, wind more backstay on (or more shrouds) and if it's too shallow, ease.

If I recall correctly on my boat (same sort of speed, size and general design as a NS38 and with a fractional rig but a much stiffer top section) tightening the forestay by about 30mm took about 7% of draft out of the jib at the top of the wind range. Then of course you have to try to ensure that with the backstay eased so that the mainsail is powered up in light airs, the forestay sags enough to power up the headsail to the right depth.

The issue with the NS38 is the very long topmast and the single spreaders, which mean that you haven't got as much bend control as a boat with double spreaders, jumpers, etc.

With a boat as popular as the NS38 I'd expect a good sailmaker to be able to give you some pretty reliable draft percentages to aim at for the new sails.

Wow thanks once again for those detailed insights.

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Stockie said..
On this topic of RIG tension. My boat has Selden, and their manual suggests tensioning the rig using a two foot rule, and measuring the stretch. Based on the rule 1mm equals 10 percent breaking strain on 1/19 stainless. I re-tensioned to these values based on my double swept back 9/10th rig.
should I bother with a loos gauge?

I did this about 3 years ago and have sailed about 3000 Mike's since, and tensions are still great!
cheers Richard

Mine is Selden too. If I don't end up springing for an expensive guage I might back it off and try that method published in their guide.

Given the ridiculous price of the larger Loos unit ($400+) I was thinking that a simple fitting with two spaced lugs sized to go onto a torque wrench would do the job nicely. Anyone handy with metal? Might even be able to adapt some existing socket. Cut the handle off an angle grinder wrench and weld the head onto a 24 mm socket??? Would calibration be a problem?

Any Sydney 38s nearby
everyboat will have one the right size

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julesmoto said..

Chris 249 said..

julesmoto said..

lydia said..
What type of boat.
Northshore 38 I think.
Pretty easy.
Set the forestay first. So 750 mm of rake at the tip
Then Caps to firm with a small not long handle spanner
You will feel when the load starts to come on.
Go for a sail, and the lowers will needs setting to match the luff round.
Do up the leeward one first and then tack
Tension on lower will generally need to match luff round ie no overbend creases.
Just keep sighting the mast track to keep it all straight.
You will never get it perfect as there will too many flaws in the mast section

Wow thanks for that. I'm assuming that you have owned or raced one. How do you set the rake? Exceptionally long plumb bob on Main halyard and very calm day? Going to get new sails so might have to see if there is weather or lee helm with them before deciding on rake.

Pardon me if I'm telling you suck eggs, but if you're going to get new sails then the sailmaker should be able to give you some pretty good hints. IMHO helm balance on a moderately modern boat, especially one as well known as the NS38, isn't much to do with mast rake. On a fractional rig, a few inches of twist or traveller will affect helm more than rake. They tend to have pretty vertical masts; I've only seen one with much rake (maybe 900mm??????) and it was quite noticeably different from the norm.

One of the critical things in rig tune on a fractional can't be done on the dock. What you're basically trying to do, generally, is to balance the increase in forestay tension (which affects jib depth) with the increase in backstay tension as you flatten the main. When the boat is set up right, the forestay sag is reduced enough that the jib reaches its proper top-end depth just as the backstay tension is increased to the stage where the mainsail matches its luff curve (as noted above) and is therefore about as flat as it will go.

So a lot of the time, you really need to know how deep your headsails should be at the top of their range, and them measure them (by taking a pic from underneath and measuring the draft on the pic) and ensure that they are getting optimum flatness as the mast bend reaches about the same amount as the mainsail's luff curve. If the headsail is too deep, wind more backstay on (or more shrouds) and if it's too shallow, ease.

If I recall correctly on my boat (same sort of speed, size and general design as a NS38 and with a fractional rig but a much stiffer top section) tightening the forestay by about 30mm took about 7% of draft out of the jib at the top of the wind range. Then of course you have to try to ensure that with the backstay eased so that the mainsail is powered up in light airs, the forestay sags enough to power up the headsail to the right depth.

The issue with the NS38 is the very long topmast and the single spreaders, which mean that you haven't got as much bend control as a boat with double spreaders, jumpers, etc.

With a boat as popular as the NS38 I'd expect a good sailmaker to be able to give you some pretty reliable draft percentages to aim at for the new sails.

Wow thanks once again for those detailed insights.

Cheers!

You could also perhaps call Scotty "Scooter" Hinton of Scooter Sails in Yamba. He is a top-class sailor, a sailmaker, and owns a Northshore 38 himself.

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julesmoto said..
Given the ridiculous price of the larger Loos unit ($400+) I was thinking that a simple fitting with two spaced lugs sized to go onto a torque wrench would do the job nicely. Anyone handy with metal? Might even be able to adapt some existing socket. Cut the handle off an angle grinder wrench and weld the head onto a 24 mm socket??? Would calibration be a problem?

Looked like a good idea until I realised it is not just the torque measurement but also the angular displacement.

Presumably there would be some simple mathematical formula which would take into account both the torque as measured by the torque wrench and the distance between the two lugs used to contact and twist the rigging wire and cause what you referred to as the "displacement". Obviously the greater the distance between these lugs the more torque would be required to create the angular displacement of thee wrench handle whereas if the two lugs were almost touching very little torque would be required to turn the wrench handle to any particular angular displacement. Either way the tension in the shroud should be proportional to the torque applied because if the lugs are far apart you are stretching the shroud a lot for any particular angle (and thus a lot of torque would be required) whereas if they are close together you are stretching the shroud much less for the same angle (thus a much smaller torque reading). It may actually be therefore that it is the torque figure that we are after irrespective of how far apart the lugs are because the torque or effort required is proportional to the stretch and hence the tension. Put another way a small angular displacement of the torque wrench handle with widely spaced lugs will create as much stretch in the wire tension as a large angular displacement of the torque wrench handle with closely spaced lugs but I the way the torque wrench reads the same for the same amount of stretch.

Any engineers here?
I'm happy to spend 15 bucks on a wrench and socket and to get a mate mate to weld the socket and angle grinder wrench and test against the genuine tension gauge if someone wants to lend me a tension gauge. Most of us probably already have a torque wrench. I certainly do.