Tuning solid rigging: advice on do's and dont's please.

[Lon nan Gruagach]

A friend has asked for help tuning the standing rigging after mast has been re-stepped. The wires are solid stainless 10~12mm dia. Mast is ~20m with 3 spreaders. Boat is all ally.
a rigger has suggested that we follow instructions from a particular web site, since while t'interweb is full of helpful forums, well, its forums, innit?
However, the recommended site is particularly obtuse and vague.

So....
What order to tighten things up, and how tight?
Do you start at the bottom and work up or top down?
Does the 1% (?) stretch rule still apply to the wires, using a wrap of tape when slack and measuring extension? I cant imagine these things being that stretchy.

Boat is a one off, so no manufacturer's info.

All replies much appreciated.

 

[lpdsn]

Was it the Selden guide you looked at? There usually quite clear. www.seldenmast.com/files/595-540-E.pdf

A 20m, three spreader rig with rod rigging is not exactly a beginner job.

Don't worry about breaking 12mm rod rigging by over-tensioning it by hand. If you can break that I'll buy you a pint.

 

[Ian_Edwards]

My boat has rod rigging and I use the Selden Mast tuning guide.

http://www.seldenmast.com/files/1456145028/595-540-E.pdf

You can use the ruler method, page 32, but note that 5% of breaking load on a 2m ruler is only 0.7mm, so tensioning to 15% or 20% of the breaking load is just 2.1mm or 2.8mm respectively,

or

You can use the sailing method, which is well described in the guide.

But if it's a triple spreader rig, you might be better advised to get a good rigger to do it, because it may mean going up the rig to adjust the D2, D3 and D4's rigging between the spreaders.

 

[Lon nan Gruagach]

Was it the Selden guide you looked at? There usually quite clear. www.seldenmast.com/files/595-540-E.pdf

A 20m, three spreader rig with rod rigging is not exactly a beginner job.

Don't worry about breaking 12mm rod rigging by over-tensioning it by hand. If you can break that I'll buy you a pint.

More worried about pulling a chain plate out or re-cambering the deck than snapping a rod.... But, I guess the builder specd the right sized rod.

My boat has rod rigging and I use the Selden Mast tuning guide.

http://www.seldenmast.com/files/1456145028/595-540-E.pdf

You can use the ruler method, page 32, but note that 5% of breaking load on a 2m ruler is only 0.7mm, so tensioning to 15% or 20% of the breaking load is just 2.1mm or 2.8mm respectively,

or

You can use the sailing method, which is well described in the guide.

But if it's a triple spreader rig, you might be better advised to get a good rigger to do it, because it may mean going up the rig to adjust the D2, D3 and D4's rigging between the spreaders.

Thanks both. The Selden guide is much much better than the one I was pointed to.
I have spent more time up that mast than I really would like to so no (more) worries with the diagonals.

 

[Clive]

I have rod rigging on my x-yacht. It is keel stepped with double spreader set up.

1) adjust fore stay to get correct mast rake, if in doubt hang weight on main halyard and measure at gooseneck, say 8 to 10 inches

2) Measure side distance from top of mast to each side deck, make both equal,

3) Tighten Cap shroud's equally by counting turns, ( use a 10" spanner and tighten almost as much as possible)

4) Tighten the D1's to reduce the pre-bend (Pull main halyard tight to gooseneck) say 4" pre-bend

5) Tighten D2's these should not need too much adjustment just to keep the mast straight sideways

6) repeat if you have 3 spreader rig.

Mark position and go for a sail up wind in say 10 knts true. see how it looks and adjust.

have fun