Rig Tension – Maintaining Your Loos….!!

Long time readers of the FF Blog may remember that we had a session to compare six of the old type of rig tension gauge – you know the old type where you pull two bits of metal apart.

The variation in readings on the same rig was simply enormous.  Hilarious and the whole thing was an obvious farce!! I immediately threw my gauge away and ordered a Loos gauge – I had heard the accuracy was true reading plus or minus one notch. I know they seem pricey, but you ought to see how much the electric ones cost… That was all probably five years ago.

Two years ago I had a moment to compare my Loos gauge and that belonging to Steve Goacher.  When Steve’s read 28.5 mine read 29.5….. bit disappointed but, hey, it was within the claimed range and I’ve been happy as pie since.

I happened to be at Phil Evans’ workshop the other day. He ran a rig up to 29 on his (new gauge) …. and mine read 27.5.  Now I would assume that despite his gauge being new, his spring was softer…. have I got that logic right??

So back at the Club Fleet, 27.5 on my gauge reads 27.5 on Chris McLaughlin’s gauge, 28.5 on Phil Tinsley’s gauge…..and all this is 29 on Phil Evans’ Champion gauge…  Oh dear – what can be going on here.  Obviously I need to complete the circle and compare to Steve Goacher’s gauge again, but can there be something else going on??

Well, what about the cams wearing?? Have you considered the effect of that?? They are soft nylon – do you, or anyone who has ever borrowed your gauge ever slide it along the shroud wire??? (“tut, tut”, I hear you exclaim…!!.)…. OK – so I might do that slightly…..

Look at the photo here – see the black spot on the upper cam??  (double click photo to enlarge). That could be an issue right there…..



OK – so what to do??  You can rotate the cams, that’s what….  First take a rig reading. Then mark the cams as shown here, so you can see the surface that you have used. Ease the holding nuts and rotate the cams a bit so they show a new surface.  Now put a new black mark so in future you know this face of the cam has been used as well. Now TAKE ANOTHER READING…. Any difference?? Well, you may have had worn cams….

2 thoughts on “Rig Tension – Maintaining Your Loos….!!

  1. Hi folks

    Another dimension to be aware of in this matter is the thickness of the wire. For example, my shrouds are both nominally 3mm Dyform construction, but actually the port one measures about 3.1 mm and the starboard one nearer 3.2 mm at the height I typically attach the tension gauge. Shroud thickness as measured does also appear to differ along the length of the wire. Starboard measures tighter by one Loos unit than the port one (I think that’s the right way round without checking my notes). Took a while to get my head round the idea that one shroud appeared tighter than the other while the mast was clearly straight, resting in the middle of the gate and the boat was upright and, and, and all the other checks.

    So what I do now is to measure tension always on the same shroud, then extrapolate back to what it ought to be with 3 mm wire. I can publish my extrapolation table if its of interest.

    Of course none of what I’ve written above alters the original postings about variability from one gauge to another

    Happy bimbling

    Martin Stainsby (3912 – HISC)

  2. Check and check again a good set of starting numbers can be invaluable; but don’t get sucked in too much, you can loose a lot in two bad tacks!

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