Shot peening standing rigging hard fixtures

[Little Sam]

Senti, raggazzino,

You've gone too far drawing comparisons with "dead passengers". That's poor taste, IMHO.

Nothing more to add. Anche per te, sperriamo.

I am not drawing comparisons........I do not need to draw comparisons. Thousands of people have died because of Metal fatigue in >Aircraft parts. FACT. A fact i will stress, that doesnt seem to exist in your head, This has nothing to do with taste , we are talking about metal fatigue are we not, so get back on point rather than making personal jibes at people that are trying to help you understand !

Oh and you can stick your Senti Reggazino straight up your culo you insulting *******o Dont write Italian to me until you know "exactly" what that means Stronzo ! However i will forgive you once due to you being English and obviously speaking what you've heard without quite knowing the severity and strength of it. so i forgive you !

 

[Skylark]

I am not drawing comparisons........I do not need to draw comparisons. Thousands of people have died because of Metal fatigue in >Aircraft parts. FACT. A fact i will stress, that doesnt seem to exist in your head, This has nothing to do with taste , we are talking about metal fatigue are we not, so get back on point rather than making personal jibes at people that are trying to help you understand !

Oh and you can stick your Senti Reggazino straight up your culo you insulting *******o Dont write Italian to me until you know "exactly" what that means Stronzo ! However i will forgive you once due to you being English and obviously speaking what you've heard without quite knowing the severity and strength of it. so i forgive you !

Stai calmo. Little Sam = raggazino, piu o meno, sono uguali, non e vero?

Me, insulting? How about culo? or stronzo?

We were trying to have a discussion about a potential benefit of shot peening a rigging bottle screw. Your comparison to death arising from airframe metal fatigue is both irrelevant and in poor taste, IMHO, but please accept my apology if it offended you.

Buona sera.

 

[Little Sam]

Buona Sera David.

Back to the OP's post.
I can and will categorically state that, the most modern super yachts and F1 cars do indeed have shot peened parts. Whether you like that, see a point in that, is of little relevance.
The OP's post asked if there would be a benefit and in my opinion and that of modern day super yacht designers, he is indeed correct, and i was only backing him up with on the job proof of his assumption that it does benefit. It does not benefit the "ordinary sailors of today". But in my line of work, i'm not thinking about today i have to think about tomorrow.

Ciao for now.

 

[puddock]

Here we go...... another pi55ing contest

 

[William_H]

To revert back to the origianls OP discussion. On our real old boats the design strength of rigging components should be way above that needed. Only in those projects seeking every gram of weight reduction does fatigue life come in to concern. Yes that is certainly the case in aviation and racing cars but not PBOs.
All the fittings on the boat concerned with rigging should be way over specced. There is just no real reason to go for lowest weight. I think this will apply also to rigging screws. How much force does it take at the chain plate to roll your boat to say 45 degrees. Not much compared to total weight of boat. This is the max tension you can get on a bottle screw.
The whole issue may have been clouded by concerns about rigging wire failure. Here we do not grossly over spec the component.
The wire does fail after a period of time. In my experience not related to cycles of load but actual calender period. it seems to be a function of corrosion failure. Obviously not practical to shot peen the wires although rod rigging would probably benefit.
good luck olewill

 

[Little Sam]

Here we go...... another pi55ing contest

All it takes is a nice PM. No one here is trying to make wars, all we want to do is try to understand better. Learn from each other. Its far from a pi55ing contest.
This thread started from a person having a hunch that shot peening hard fixings could be of benefit.

However.....i-m not not shy when it comes to a pissing contest in engineering.... so shoot away cowboy !

 

[vyv_cox]

As has been said, rigging failure due to fatigue is not common but it certainly does happen. The one I am most familiar with is on some older designs of T-ball fittings in which the bend between the ball entry and the swaged shank was made at an angle too acute and resulted in the T-ball being offset from the swage. An example was shown in YM about two years ago. I have also seen fatigue failures in perforated types of bottle screws that had abrupt changes of section. There is a nice example of fatigue failure in a mast tang on my website.

These are all examples of poor design leading to fatigue failure. You could shot-peen them for hours but it would not extend their life by a lot. Whereas with a well-designed component like the one shown above the likelihood of fatigue failure is so low that it is most unlikely, without the need for peening. My understanding is that peening contributes well under 10% to the fatigue life of most materials, although I have no expertise in titanium.

 

[smeaks]

As has been said, rigging failure due to fatigue is not common but it certainly does happen. The one I am most familiar with is on some older designs of T-ball fittings in which the bend between the ball entry and the swaged shank was made at an angle too acute and resulted in the T-ball being offset from the swage. An example was shown in YM about two years ago. I have also seen fatigue failures in perforated types of bottle screws that had abrupt changes of section. There is a nice example of fatigue failure in a mast tang on my website.

These are all examples of poor design leading to fatigue failure. You could shot-peen them for hours but it would not extend their life by a lot. Whereas with a well-designed component like the one shown above the likelihood of fatigue failure is so low that it is most unlikely, without the need for peening. My understanding is that peening contributes well under 10% to the fatigue life of most materials, although I have no expertise in titanium.

The fatigue life of a component is dependant upon the loading of the material and the tensile/compressive nature of the static stresses within the component at unloaded rest. A lightly loaded component will fail after many cycles as the load increases the cycle life will reduce and as the load approaches the UTS of the material the component will fail within one cycle.

Many materials benefit huge gains in cycle life from peening. Automotive steel springs have been proved to have cycle improvements of x1000 to infinite depending upon the load.

As little Sam explained the whole manufacturing process and design has to be considered to maximise cycle life. What is cutting edge F1 tech today will end up in your mondo in ten years. In aerospace engine components were peened as belt and braces contingency but now as alloys become more exotic and weight decreased it is an integral design component.

A very good point made was that the wire corrosion is a limiting factor before the failure of the bottle screws etc... Or is that the swagged connectors cracking and releasing the wire?

Also a well made and designed component will hopefully outlast the rigging but with the need for profit maximisation by manufacturers of yachts may lead to the provision of less than top grade gear which is then left to gorillas like me armed with screw drivers and shifting spanners. If a relatively cheap process like shotpeening can add life and user confidence to such components it makes sense to consider it.

 

[vyv_cox]

The x1000 is for very specific cases. Nobody is going to get anywhere near that for rig components. For shafts and similar components that I have worked with the 10% figure is more realistic.

 

[wotayottie]

Because if you read the thread, we are not talking about "ordinary sailing".

We are talking about taking boat components to a new level. Well at least i am, and the OP, by the sounds of him too.

The OP drives a Moody 27 - a splendid boat but hardly sailing to a "new level". And you arent saying much anyway - you seem to have some sort of secret squirrel complex.

For ordinary sailing boats of the sort we own on this forum, the issue of fratigue of rigging screws doesnt exist. If it did, we wouldnt be looking at titanium or even the sort of high grade stainless steels that would reduce risk. Instead we would simply be putting bigger versions of existing fittings on the boats and making sure they were properly articulated.

On another subject, have Ferrari got their wind tunnel working properly yet?

 

[Little Sam]

Hi Wotatotty
We are not talking about what the OP "Drives". We are not talking about what you drive or what anyone else on this forum drives.
We are talking about what you could well be using in the future. So please dont take the pi55 out of people that work hard to make your life easier.

Or would you rather haul your big massive weigh a ton boat bits around ! The use of super light super strong shot peened components on Boats has already begun. Whether you like that or not or indeed fancy throwing your weigh a ton combine harvester at it is irrelevant, that's the way it is !

 

[puddock]

Hi Wotatotty
...

Or would you rather haul your big massive weigh a ton boat bits around ! The use of super light super strong shot peened components on Boats has already begun. Whether you like that or not or indeed fancy throwing your weigh a ton combine harvester at it is irrelevant, that's the way it is !

You really are an arrogant, self opiniated prat aren't you Little Pecker?

 

[Little Sam]

You really are an arrogant, self opiniated prat aren't you Little Pecker?

Hi Puddock.

It takes a real man to insult over the web, however i reckon you love me alot seen as you specifically take time out to post about me. And only me ! I love you too.
Do tell us about life in Peterhead ? it must be very exciting all those drunks and pharmacies that have forgotten the antidepressant stocks.

Oh and its "Opinionated", Dear Puddock.

 

[puddock]

Hi Puddock.

It takes a real man to insult over the web, however i reckon you love me alot seen as you specifically take time out to post about me. And only me ! I love you too.
Do tell us about life in Peterhead ? it must be very exciting all those drunks and pharmacies that have forgotten the antidepressant stocks.

Oh and its "Opinionated", Dear Puddock.

Sorry, don't have much info on life in Peterhead, as I merely park the boat there.
As for "it takes a real man to insult over the web" , believe me, it would not be my preferred option as I would much prefer the opportunity for a more hands on approach. Likewise, I am sure that if you were having the above discussion with Wotayotty in real life, you would (I'd hope) reply in a slightly less insulting manner to him.
That aside, I don't know the REAL you and for all I know you are probably a perfectly reasonable and sociable person to be around, so I wont get into a p*55ing contest with you.
I was probably influenced by my (likely highly inaccurate) presumption of you being a desk bound engineer and my inbuilt distrust (from personal 'field' experience) of them ie :- Most I have met could tell me the square root of an egg but wouldn't have a clue how to make an ommelette.

Anyway, fair winds and remember I love you

Take care