Shroud tension

[Peter Hill]

Hi all. Nice to see the website back up. Just testing parts of it.
My mac wight mk2 is in the yard at milford having hull blasted and epoxy tretment. Still not put the masts back on yet. My question is in what order you tighten all the tensioners and how much tension. Told once before that you tighten them all hand tight first then half a turn with a screwdriver. Sounds fine but but presumsbly as you apply tension on one side it will similarly tension the other side as the mast bends slightly so how do you ensure even tension?

[Rob Wombwell]

Hi Peter

Not sure about what I’m saying here but it’s sounds logical that if you tighten one side a half turn and then the other half a turn, wouldn’t that be the same as one turn either side and equal tension? I’m getting a headache thinking about it.
I have to admit that before I slackened off the rigging the last time I lowered the mast, I marked the turnbuckles with tape so I knew roughly how much tension to apply. I do recall using a tape measure, a piece of string and a strip of cardboard in the past to measure the tension but can’t remember the measured distance. Sorry I couldn’t be more helpful, I, like yourself will wait for the post of someone more knowledgeable.

Regards
David

[Rob Wombwell]

There’s an article on Rig tensioning in this months Pratical Boat Owner may be of some use.

David

[Bob & Freddy Tuffnell]

I have just ordered a set of replacement standing rigging for “Dauphin Blanc” my 1976 Mac 27 Mk II, so will ask my rigger to explain his ideas on how to set it up, and will give you a new post on the subject, if it is radically different from what I describe here.
My recollections from what happened at Littlehampton is that the slack was taken up all round, having first determined that the forestay, (which on my Rotostay is using 6mm wire, the rest is in 5mm) is at the correct position to give the desired mast rake, that is to say vertical.
Then cap shrouds and backstay(s) are gradually tightened up, to give a “firm” feeling. finally the lower shrouds, taking care to sight up the mainsail track on the mast, to keep the spar straight. Nothing should be so much under tension that it is singing middle C !
Everything seems to indicate that what I have taken off was the original equipment as supplied by Macwesters 40 years ago! Close inspection did reveal a total of 3 broken strands, one on a lower shroud, one on a cap shroud, where it passed over the spreader end, and one at the crimp of a Talurit eye. Oddly never 2 on the same length of wire! I know that the lower shroud went at the end of last season, whilst creaming along on a fine reach at over 7 knots. needless to say I immediately luffed up a bit, and took in a generous reef…..
All the same, it seems a long way from the 5 to 10 years lifetime of standing rigging that some insurers seem to want to impose; Business is business???

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