Rigging Tension - a different angle

[Cappen Boidseye]

A friend of mine told me that he takes some of the tension off his standing rigging for the Winter, however, I thought that an alloy mast would expand and contract more with temperature than stainless steel shrouds. I must admit that I had never even thought of differential expansion of rigging and masts until he mentioned it and would never have thought of seasonal adjustments.
Does he have a point?

 

[Javelin]

Fractional or Masthead?

I can see a case for fractional as the loadings are pretty high on compression and on the boat, although I'd back up the backstay with the main halyard.

Masthead rig less so as the loading is a lot less but there needn't be much if any backstay tension, just take the slop out.

 

[Lakesailor]

It all shrinks in winter so will all go floppy anyway. Like....erm....

 

[Cappen Boidseye]

Masthead rig, Sadlet 26. He thought that the rigging would contract more than the mast and would therefore increase stress, I think the opposite would happen as alloy contracts more than stainless, or does it?

 

[Lakesailor]

Aluminium alloys in the 12.8/13.2 range (microinch/(in oF))
Stainless steel in the 5/10 range (microinch/(in oF))

That is the CoE so presumably Alloy will contract more than SS in colder conditions.

 

[sailorman]

Masthead rig, Sadlet 26. He thought that the rigging would contract more than the mast and would therefore increase stress, I think the opposite would happen as alloy contracts more than stainless, or does it?

If allowed to be slack the stays will be prone to fatigue at the swage terminals

 

[Deleted member 36384]

If allowed to be slack the stays will be prone to fatigue at the swage terminals

+1 This is poor practise and can lead to early failure of rigging, it is a n=known cause of premature failure. However, there is reduced tension and slack rigging, the former should be OK as long as the tension is still sufficient that all the stays feel firm.

 

[Cappen Boidseye]

I never said slack, I have always presumed he just eases the tension a bit, however, if the tension is reduced as the various bits contract in the cooler Winter temps, he is wasting his time reducing the tension further. Most years I have had my mast lowered so that I can do things to the bits at the top end and also because when the boat is up on the hard and a force 10 or 11 gale is blowing, I am a lot more relaxed if the mast is down and not trying to turn the boat on it's side.