vyv_cox
Well-Known Member
Why? What does age have to do with condition? Inspect thoroughly and if no faults reuse them.
Rigging Toggles - replace (@ £300!) or reuse?
- Thread starter dankilb
- Start date
[70521]
Well-Known Member
I worked as a safety engineer in a safety critical industry. Unless the component's history was known it was binned period.
Age will have an impact on the number of 'cycles' that the component has been through.
Given all we have from the OP is, 'I've got some bits that I want to use again', my interpretation is that nobody has a clue how close they are to the mean time to failure - we will have both seen that components do just fail (I am a fan of your website). While it is clearly the OPs decision and only they will know if cross oceans or enjoy a day sail in F4 with a slight sea is their thing. Personally, I'd spend a few hundred pounds more now than have a dissmast on a dark and stormy night.
vyv_cox
Well-Known Member
My point is that Time-based maintenance is good for components that degrade with age or use such as oil, rubber, filters, etc. Items made from metal do not degrade due to age alone. Therefore Condition-based maintenance is appropriate, based on inspection. Fatigue and/or corrosion can be identified quite readily by visual inspection.
The vast majority of equipment is maintained today using this philosophy.
penberth3
Well-Known Member
No. Amount of use = Number of cycles. It isn't proportional to age.
[70521]
Well-Known Member
Who sits and counts cycles unless you have very good records or instrumentation to do so? Age is a rough guide to use. Ask any mass manufacturer they will or should know the mean time to failure on their components as they
On aircraft some components are on one of three variables: Time on aircraft; number of landings or hours in the air. Whatever hits the limit first governs when the component is removed, e.g.
An aircraft can sit on the ground for six months item comes off;
An aircraft lands four times a day for 2 months item comes off;
An aircraft flies 18 hours a day for six weeks item comes off.
bitbaltic
Well-Known Member
That’s fine if you’re competent to make an inspection; not everybody would feel that they are. That’s why we get the 10 year rule of thumb for standing rigging.
I had the local riggers round today to replace a guard wire that has unstranded. Their advice was to replace all the guard wires as one has gone. They’re professionals and weren’t keen to godown a condition based route even on relatively less critical parts.
the question is how you mitigate the risk of failure- outright replacement or confident inspection. If you don’t know which way to go, you can go backwards through the question by asking yourself what financial cost you would be willing/able to bear in the moment that the risk (demasting) matured. At that point a mitigation cost of £300 I suggest would look to most people like a good decision.
dismastings do happen and I doubt any skipper watched it pitch into the briny and said, well I was expecting that because I was accepting a certain amount of risk around component x.
not saying which way the OP should go but the question is more about how a skipper approaches risk management than the components themselves really.
vyv_cox
Well-Known Member
We are not talking about a total rigging inspection, these are a few toggles held in the hand. Anyone can see cracks with a decent magnifying glass.
PetiteFleur
Well-Known Member
I replaced my rigging 4 yrs ago - on insurance insistence. Several faults found, including the baby stay mast fitting and bottle screws. There were also several toggles at various places which the rigger replaced with toggled bottle screws. The old toggles, which were the solid type, I sold on ebay.
dankilb
Well-Known Member
What has now become the main issue, for me, is not being able to source identical like-for-like replacements. Without which, I’m left wondering how the new toggles with a one-third gap would perform against the existing ones (with an unbroken strap of 5mm stainless, showing only minor wear across a few mm of bearing surface).
Ours isn’t a very common mast extrusion/rig supplier (Francespar) and many of the parts are quite unique (like the in-mast furler) and still working well. We couldn’t replace everything even if we wanted to (without a new mast!).
I do. 30 years. However the level of ‘wear’ and apparent cycles seems very low. Things we’ve rebuilt, like all the winches and the forestay furler(s), have shown what I’d describe (sadly) evidence of minimal wear and maximal neglect. The great thing about the rig re-fit has been that the bits up the mast only show the minimal wear! (They’re too far out of reach for the neglect!)
Ours isn’t a very common mast extrusion/rig supplier (Francespar) and many of the parts are quite unique (like the in-mast furler) and still working well. We couldn’t replace everything even if we wanted to (without a new mast!).
I do. 30 years. However the level of ‘wear’ and apparent cycles seems very low. Things we’ve rebuilt, like all the winches and the forestay furler(s), have shown what I’d describe (sadly) evidence of minimal wear and maximal neglect. The great thing about the rig re-fit has been that the bits up the mast only show the minimal wear! (They’re too far out of reach for the neglect!)
bitbaltic
Well-Known Member
In risk terms there is not a difference because dismasting is the risk outcome.
your case (which I don’t argue with) is that mitigation by inspection is appropriate and in point of fact easy. But the risk isn’t likely to be different or less if a single toggle fails- down will come your mast. So your inspection must be fit for the mitigation purpose, and the easiness of inspection must be so great that it negates a spend of 300 quid.
a full rig check isn’t looking for a series of cumulative problems that could bring down your mast. It’s looking for any single weakness that might do so. So there is absolutely no difference in a ‘full rig inspection’ versus the inspection of a single component if the competence of that component is doubtful.
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[70521]
Well-Known Member
As my late father, a marine engineer, would say, it don't owe you much.
If you are keen to use the component, I'd talk it over with your insurance company as it will be their decision to pay out or not should there be a failure.
There is no way that you know the apparent cycles. I had a finger on my backstay when Storm Eunice came through, according to the instrumentation the highest gust was 67 knots, the vibration was interesting. I could not count the cycles.
DownWest
Well-Known Member
While maintaining aircraft, dye testing was usually used if we suspected a crack after visual inspection. I used to keep a little pen microscope handy.
bignick
Well-Known Member
Additionally, decent quality old stuff might be a higher grade than a cheap new replacement.
ean_p
Well-Known Member
Isn't the root of your maintenance philosophy one of constant change out to remove any chance of unfound deterioration,ending in a simple question of when and not if an item , an assembly, a system is replaced. It may in this instance be £300 for a few toggles but that is only as the scope of / focus of renewal has been limited. Going forward with your question regarding risk maturing. Well I can't think of anything which should it fail I wouldn't have given its cost ( and usually multiples of its cost) if I could go back to have prevented it's failure.
It's a fine philosophy especially when time and cost is no object.
And of course it has a flaw I think...... statistically don't ' things' tend to fail more often when new / disturbed with a gradual fall in the rate of failure ?
An awkward question at the best of times all round!
AntarcticPilot
Well-Known Member
A lot of people seem to be missing the OP's main point - that direct replacements of the equipment aren't available, and he's uncertain that possible alternatives would be as strong or as long-lasting. In that case, surely the risk assessment must change - is it a bigger risk to retain the tried and tested original after careful inspection (perhaps including dye penetration) or to rely on an untested and significantly different piece of equipment that isn't what the original designer intended? It seems to me that the OP raises cogent points about the smaller cross-section and bearing surfaces of the new equipment. The philosophy of "replace after N years" (or N cycles or whatever) can only work IF there's a direct replacement for the original equipment. In this case, I think that I'd be quite happy to subject the original equipment to non-destructive testing and assuming it passes, continue to use them. It strikes me that the only alternative that would be better would be to take the parts along to a metal fabricator and get new ones made from scratch (given that they're quite a simple design, I doubt that would be expensive). However, identifying the material and any necessary treatment might well be difficult.
dankilb
Well-Known Member
Thanks AntarcticPilot, Vyv and others - that is indeed my concern. These original jaw toggles were made to fit the masthead and seem to be of high quality.
There are other parts (like the tensioner) that also need to be reused due to cost/availability. So it’s a question of sorting what gets reused and what gets replaced.
If identical toggles were available (even at £200) I’d probably but by no means definitely go for replacement.
Does anyone know why the current toggle design has the gap in the middle of the ‘U’? I assumed it was to take a rigging eye. But looking at pics of installations, it seems they are used exactly like the current ones. Perhaps the gap allows rainwater to clean the bearing surface? (In semi-seriousness). I can’t see another reason for reducing the area/material/strength by one third.
As an interesting aside, when discussing with the engineers, their take was ‘this’ll never break, mate’. They weren’t marine/boat people and I did try to stress the loads and implications of failure…!
There are other parts (like the tensioner) that also need to be reused due to cost/availability. So it’s a question of sorting what gets reused and what gets replaced.
If identical toggles were available (even at £200) I’d probably but by no means definitely go for replacement.
Does anyone know why the current toggle design has the gap in the middle of the ‘U’? I assumed it was to take a rigging eye. But looking at pics of installations, it seems they are used exactly like the current ones. Perhaps the gap allows rainwater to clean the bearing surface? (In semi-seriousness). I can’t see another reason for reducing the area/material/strength by one third.
As an interesting aside, when discussing with the engineers, their take was ‘this’ll never break, mate’. They weren’t marine/boat people and I did try to stress the loads and implications of failure…!
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DownWest
Well-Known Member
They are used when fastening to a tang like a flat chainplate that goes in the slot. or the 'spade' end of a turnbuckle when fastening to a u-bolt, as used on some boats as chain plates. Usually the latter.
Here: Rigging Toggles - Stainless Steel - Jaw and Eye | S3i Group