Join Date: Sep 2003
Location: Auckland New Zealand
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Re: Mast Life and When to Replace It ?
This is just a personal view so don't adjust your set.
A mast generally speaking is not subjected to a huge amount of changing load that would work-harden the material. Most of the load on a mast is a compressive load induced by the stay wires, shrouds. Those same stays, shrouds serve to fully support the mast section and reduce (almost eliminate) any movement.
The side loads on a mast are induced by the luff of the sail in the track and that is supported along the entire length of the mast which does not create localised stress and only localised stress will cause failure. All the side load is borne by the rig (cables). An aircraft is obviously different because wings, elevators, rudders are unsupported and do all the load bearing themselves with the associated flexing and consequently the work-hardening.
As a support argument for this, I once had an inner lower diamond stay bottle screw fail on a mast. The movement on the mast without that stay was something to behold - it was extreme - and there was no movement there when the stay was correctly in place and tensioned.
It is my considered opinion that if the rig is in good shape and correctly set up, the mast section will last for a really long time unless there are obvious signs of corrosion or physical damage.
Whilst it is imprudent to rule it out, in my experience broken masts have always been the result of a stay wire letting go and not the collapse of the mast section. I can't recall seeing a mast fail without a wire breaking first.
Oh, Maybe using an inner baby stay in a lumpy sea without running back stays will cause excessive movement that can cause a mast to collapse but this is probably poor seamanship more than anything.
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