Rigging question
- Thread starter Bonzai
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Materials that endure constant load cycling ultimately 'get tired' and then can no longer bear loading as when 'new'; in metals the constant load cycling results in 'metal fatigue' or embrittlement (cold working).
If one would take any form of stainless steel, lay it on the ground and not use it, there would be no increase in metal fatigue or other loss of strength for probably 1000s of years.
Your rigger has to protect himself, as if he says 'it looks good' and it fails anytime in the long term future, you will sue him and ultimately win. Such is the 'game of risk' in the litigious USA. The rigger HAS to protect himself, legally.
The same would follow for insurance carriers, as the actuarial numbers show that for a seldom used recreational boats that rig failures begin to show up as casualty loss at 10 years ... then the recommendation (usually 'snuck' into your policy 'fine print' at the time of renewal) from them is to demand "change ALL rigging in all boats AT 10 years" ... because a failed rig sets a 'precedent' both legal and actuarially. Have a policy that states "rigging changeout at 10 years" and you dont and it fails ... YOU pay (and pay for all consequential damages,etc.), they dont. If you hardly use the boat, the rigging still has be changed ... protects the insurance carrier from casualty loss.
Rigging fails typically because of TWO simultaneous failure modes ... fatigue AND chemical corrosion.
Fatigue (micro cracks) 'normally' begins in stainless when the material is loaded beyond ~30% of ultimate tensile strength ... the beginnings of these small micro cracks begin to form, although micro cracks are and can be started in the forming process of the new material. Every load cycle above ~30% increases the ever additive amount of micro-cracks. Typically when there are 1 million load cycles above 30% the part fails, can be quite catastrophically - without warning and at loads that are quite low. On a properly designed rig it will become fatigued typically after 1 'circumnavigation' (1 million load cycles at greater than 30% UTS).
Never ever load 300 series stainless steel beyond 30% of ultimate tensile strength ... and the fatigue 'endurance' becomes towards 'infinite'. That 30% UTS value in stainless is called 'the fatigue endurance value' ... usually determined by ACTUAL cyclical destructive testing on the 'actual' part.
Chemical Corrosion - Those microcracks allow moisture to penetrate into the metal on a macroscopic basis. When the cracks penetrate/propagate deeply into and beyond the surface, that penetrating water quickly loses its excess oxygen and without oxygen in a wet atmosphere the stainless begins to rust (internal to the material). The telltale 'rusting' of chemical (crevice) corrosion is 'rust blooms' on the surface of the material. Rusting of the iron component of stainless steel generates extreme internal pressure ... which in turn, enhances microcracking, which accelerates the chemical corrosion, which enhances the microcracking, etc. etc. etc.
So, ignoring insurance considerations, when do you change rigging?
1. anytime you see a visible crack - signifies 'embrittlement' or fatigue - the 'beginnings' of catastrophic FAILURE.
2. anytime you see any 'zone' on the surface of the stainless that shows 'dulling' or loss of surface 'sheen'. The shiney surface becomes 'dull' - indicator of 'fatigue'.
3. anytime the stainless develops 'rusting' (other than cosmetic surface rust due to 'surface roughness', etc.).
4. anytime the stainless has cracks AND rusting is emanating from the micro-cracks ... and rust seems to be 'pouring' or is being 'pushed' out of the component ... even on a macro-scale view.
5. anytime the component permanently changes dimension (ductile failure)
6. when 'proof loading' to approx 70-80% of ultimate tensile values results in failure (very dangerous to do and I dont recommend for YOU to do this). These are very crude approximate values.
On boats that are actually/frequently sailed, any rig should have an 'up the mast' inspection for fatigue/cracks/'rust' every season.
Any rig should have a mast-off detailed inspection, including 'dye penetrant' and/or 'magnetic' inspection approx. every 5 years.
If you know how (ONLY if you know how and without risk of killing yourself as this is quite 'dangerous') proof loading to validate remaining 'strength'.
If one would take any form of stainless steel, lay it on the ground and not use it, there would be no increase in metal fatigue or other loss of strength for probably 1000s of years.
Your rigger has to protect himself, as if he says 'it looks good' and it fails anytime in the long term future, you will sue him and ultimately win. Such is the 'game of risk' in the litigious USA. The rigger HAS to protect himself, legally.
The same would follow for insurance carriers, as the actuarial numbers show that for a seldom used recreational boats that rig failures begin to show up as casualty loss at 10 years ... then the recommendation (usually 'snuck' into your policy 'fine print' at the time of renewal) from them is to demand "change ALL rigging in all boats AT 10 years" ... because a failed rig sets a 'precedent' both legal and actuarially. Have a policy that states "rigging changeout at 10 years" and you dont and it fails ... YOU pay (and pay for all consequential damages,etc.), they dont. If you hardly use the boat, the rigging still has be changed ... protects the insurance carrier from casualty loss.
Rigging fails typically because of TWO simultaneous failure modes ... fatigue AND chemical corrosion.
Fatigue (micro cracks) 'normally' begins in stainless when the material is loaded beyond ~30% of ultimate tensile strength ... the beginnings of these small micro cracks begin to form, although micro cracks are and can be started in the forming process of the new material. Every load cycle above ~30% increases the ever additive amount of micro-cracks. Typically when there are 1 million load cycles above 30% the part fails, can be quite catastrophically - without warning and at loads that are quite low. On a properly designed rig it will become fatigued typically after 1 'circumnavigation' (1 million load cycles at greater than 30% UTS).
Never ever load 300 series stainless steel beyond 30% of ultimate tensile strength ... and the fatigue 'endurance' becomes towards 'infinite'. That 30% UTS value in stainless is called 'the fatigue endurance value' ... usually determined by ACTUAL cyclical destructive testing on the 'actual' part.
Chemical Corrosion - Those microcracks allow moisture to penetrate into the metal on a macroscopic basis. When the cracks penetrate/propagate deeply into and beyond the surface, that penetrating water quickly loses its excess oxygen and without oxygen in a wet atmosphere the stainless begins to rust (internal to the material). The telltale 'rusting' of chemical (crevice) corrosion is 'rust blooms' on the surface of the material. Rusting of the iron component of stainless steel generates extreme internal pressure ... which in turn, enhances microcracking, which accelerates the chemical corrosion, which enhances the microcracking, etc. etc. etc.
So, ignoring insurance considerations, when do you change rigging?
1. anytime you see a visible crack - signifies 'embrittlement' or fatigue - the 'beginnings' of catastrophic FAILURE.
2. anytime you see any 'zone' on the surface of the stainless that shows 'dulling' or loss of surface 'sheen'. The shiney surface becomes 'dull' - indicator of 'fatigue'.
3. anytime the stainless develops 'rusting' (other than cosmetic surface rust due to 'surface roughness', etc.).
4. anytime the stainless has cracks AND rusting is emanating from the micro-cracks ... and rust seems to be 'pouring' or is being 'pushed' out of the component ... even on a macro-scale view.
5. anytime the component permanently changes dimension (ductile failure)
6. when 'proof loading' to approx 70-80% of ultimate tensile values results in failure (very dangerous to do and I dont recommend for YOU to do this). These are very crude approximate values.
On boats that are actually/frequently sailed, any rig should have an 'up the mast' inspection for fatigue/cracks/'rust' every season.
Any rig should have a mast-off detailed inspection, including 'dye penetrant' and/or 'magnetic' inspection approx. every 5 years.
If you know how (ONLY if you know how and without risk of killing yourself as this is quite 'dangerous') proof loading to validate remaining 'strength'.
Don on rigging
I admit that I did not change out my standing rigging at the 10 year mark. However, I did climb the mast and fully inspect it for any signs of cracks etc. several times over the next couple of years. The big problem with not fully inspecting (i.e. pulling the chain plates etc.) the rigging, you may not know what is happenning below the surface. If a chain plate did fail under any serious loads the whole rig could come down. That would cost a lot more than a standing rigging replacement.
Now, replacement does not guarantee that the rig will not come down but you cannot know how much better it feels once you do replace the rigging. It's really not that expensive!
I admit that I did not change out my standing rigging at the 10 year mark. However, I did climb the mast and fully inspect it for any signs of cracks etc. several times over the next couple of years. The big problem with not fully inspecting (i.e. pulling the chain plates etc.) the rigging, you may not know what is happenning below the surface. If a chain plate did fail under any serious loads the whole rig could come down. That would cost a lot more than a standing rigging replacement.
Now, replacement does not guarantee that the rig will not come down but you cannot know how much better it feels once you do replace the rigging. It's really not that expensive!
While we're on the subject of standing riggng replacement, I have a question (that will probably get both ends of the spectrum for an answer(s)). So here goes:
I own an Island Packet 29 and I want to replace the standing rigging too. So I have four options I'm considering:
1) Replace it size for size with new swaged fittings, wire, etc.
2) Replace it with swageless fittinngs size for size.
3) Replace it with swageless fittings with one size wire (1/4") so that I only need to carry one size wire and parts as spares.
4) Replace it (OK here we go....) with 1/4" Dyneema all the way around. The 1/4" Dyneema is stronger than the 1/4" wire that is the largest size on the boat now.
I have seen Dyneema on a Westsail 32 at the Annapolis Sailboat show several years ago, so I know it has been done, just don't know to what successl.
BTW, I am planning on replacing the lifelines with 1/4" Dyneema.
Thanks,
Bill
TRINITY IP-29-10
I own an Island Packet 29 and I want to replace the standing rigging too. So I have four options I'm considering:
1) Replace it size for size with new swaged fittings, wire, etc.
2) Replace it with swageless fittinngs size for size.
3) Replace it with swageless fittings with one size wire (1/4") so that I only need to carry one size wire and parts as spares.
4) Replace it (OK here we go....) with 1/4" Dyneema all the way around. The 1/4" Dyneema is stronger than the 1/4" wire that is the largest size on the boat now.
I have seen Dyneema on a Westsail 32 at the Annapolis Sailboat show several years ago, so I know it has been done, just don't know to what successl.
BTW, I am planning on replacing the lifelines with 1/4" Dyneema.
Thanks,
Bill
TRINITY IP-29-10
Re: IMHO
Can anyone provide a SWAG at what it would cost to replace the standing rigging on a Hunter 33.5. Reading this post has got me thinking since the boat is 19 years old and I have no idea if the standing rigging has ever been replaced, I may need to look into this. When the boat was surveyed the surveyor stated he was not qualified to inspect standing rigging and did not do it.
Can anyone provide a SWAG at what it would cost to replace the standing rigging on a Hunter 33.5. Reading this post has got me thinking since the boat is 19 years old and I have no idea if the standing rigging has ever been replaced, I may need to look into this. When the boat was surveyed the surveyor stated he was not qualified to inspect standing rigging and did not do it.
Hey Bbowman
As a general rule you should not mess with the wire sizes for the following reason.
If a structure is designed to fail in a certain way so as to, let’s say, not rip the cabin roof off at the chain plates but to just have the fitting fail and suffer a demasting then strengthening any part of the structure could put your boat in a situation where when over stressed the cabin top does come off first and you suffer a demasting and have a big hole in the top to let the water in.
This is engineering stuff and should be left to the engineers so you do not compromise the "fail safe" designs built into the boat.
As a general rule you should not mess with the wire sizes for the following reason.
If a structure is designed to fail in a certain way so as to, let’s say, not rip the cabin roof off at the chain plates but to just have the fitting fail and suffer a demasting then strengthening any part of the structure could put your boat in a situation where when over stressed the cabin top does come off first and you suffer a demasting and have a big hole in the top to let the water in.
This is engineering stuff and should be left to the engineers so you do not compromise the "fail safe" designs built into the boat.
Hey Paul.My rigger only charged $50 to inspect the rig and give me an estimate. He deducted that from any work done, also.
Re: IMHO
Replacing is smart. Don't wait until one wire breaks THEN have to buy all new rigging and a $2,000 mast like I had to. The wire that broke was caroded within the fitting where you COULD NOT SEE it! 10 years salt water, 15 years fresh water is what I have sinced learned is a good time to change out your wire.
Replacing is smart. Don't wait until one wire breaks THEN have to buy all new rigging and a $2,000 mast like I had to. The wire that broke was caroded within the fitting where you COULD NOT SEE it! 10 years salt water, 15 years fresh water is what I have sinced learned is a good time to change out your wire.
Check with Seco South (FL). They have excellent service and pricing.
I would suggest replacing it if you are unsure. Are you going to re-rig the boat yourself?
I would suggest replacing it if you are unsure. Are you going to re-rig the boat yourself?
Some reasonable questions: There is mention of loading the standing rigging to not exceed 30% of breaking strength, that allows only a 3.3 :1 safety factor. That is inadequate where life and property are at risk. How are sizes determined?
Fatigue is a factor when loading exceeds 30% of breaking strength. Fatigue could be taken out of the concern with adequate wire size. Why isn't it standard proceedure?
Fatigue is a factor when loading exceeds 30% of breaking strength. Fatigue could be taken out of the concern with adequate wire size. Why isn't it standard proceedure?
Way to go Ross, external chainplates is the way to go. The upgraded wire is nice touch too. No wonder you say "thirteen years and I'm not even considering replacing it" HoHum...
Rigging is an expensive part of boat construction.
At least for purpose built offshore boats most rigging is at or above 3 to 1 safety factor, some at 4:1 ... and this equates to a boat being theoretically pulled or artificially heeled over by its mast to a 45 degree angle and the theoretical developed load to do this determines the 'wire size'. Rarely do you ever see 'rigging fatigue' in a purpose built offshore boat, but it still happens as a two phase failure - both fatigue and chemical corrosion happening simultaneously.
Just remember that aircraft only have a lifetime of so many take offs and landings, then its to the junk yard because their metal has become 'too tired' to remain 'reliable'. Its also the same reason that you dont see many 40 year old cars driving around ... embrittlement of the 'undercarriage'.
Having the rigging done by a local professional. He was recommended by sailing friends there, name is Ritchie.
We were approaching Jupiter Inlet on Florida's east coast, when a boat that had just left the inlet called Towboat US and reported that his mast had just come down. Seems he had just had the standing rigging repaired and was on a sea-trial. Something about a missing cotter-pin. Ouch! As we passed the inlet, we saw Towboat US escorting the sailboat, with the rigging hanging over the side, as they headed back to the boatyard. I was glad that I wasn't an employee at that yard on that particular day.
RichH, Thank you for your answer.The cost difference between 3/16 and 1/4 inch cable for rigging is small relative to the labor to install. I realize that most builders work to the most likely usage.
I have also heard weight aloft as a reason but the difference in weight is small especially when considered against the added weight of rain wet sails.
I have also heard weight aloft as a reason but the difference in weight is small especially when considered against the added weight of rain wet sails.
There are a lot of good comments/opinions about whether or not to replace the rigging, so I'll leave that subject alone. However, I suspect more rigging fails from the loss of clevis pins and cotter pins than wire or fitting failure. Here's a link to a great article from BoatUS on Inspecting Your Boat's Mast and Rigging.
http://www.boatus.com/seaworthy/rigging/default.asp
This is on the top of my list this Spring.
Ross wrote:
"Some reasonable questions: There is mention of loading the standing rigging to not exceed 30% of breaking strength, that allows only a 3.3 :1 safety factor. That is inadequate where life and property are at risk. How are sizes determined?
Fatigue is a factor when loading exceeds 30% of breaking strength. Fatigue could be taken out of the concern with adequate wire size. Why isn't it standard procedure? "
There are lots of structures out there that you use every day that have a safety factor of only 2, most highway bridges and reinforced concrete buildings come to mind.
The idea of making something so strong it will not fail is not exactly how the topic was discussed during my days at college. You design things so they fail in a predictable fashion of your choosing and don't leave it to Mother Nature to pick your failure mode. The idea of a fuse in an electrical circuit is exactly this type of thinking. I design a weak link in the system so that when it does fail it does so in a designed way and not just goes up in smoke and burns the boat to the waterline.
For a sail boat rig you have to consider the possibility that the rig will tear the top off the boat as a failure mode. Given that the seas will probably be high when this happens that would be what we like to call a 'less desirable mode of failure'. Better to have the links at the chain plates fail first and loose the rig than to lose the rig and have it take the cabin top with it IMHO (and others too).
Given all that it may not be possible to design the rig so as to eliminate fatigue failure.
"Some reasonable questions: There is mention of loading the standing rigging to not exceed 30% of breaking strength, that allows only a 3.3 :1 safety factor. That is inadequate where life and property are at risk. How are sizes determined?
Fatigue is a factor when loading exceeds 30% of breaking strength. Fatigue could be taken out of the concern with adequate wire size. Why isn't it standard procedure? "
There are lots of structures out there that you use every day that have a safety factor of only 2, most highway bridges and reinforced concrete buildings come to mind.
The idea of making something so strong it will not fail is not exactly how the topic was discussed during my days at college. You design things so they fail in a predictable fashion of your choosing and don't leave it to Mother Nature to pick your failure mode. The idea of a fuse in an electrical circuit is exactly this type of thinking. I design a weak link in the system so that when it does fail it does so in a designed way and not just goes up in smoke and burns the boat to the waterline.
For a sail boat rig you have to consider the possibility that the rig will tear the top off the boat as a failure mode. Given that the seas will probably be high when this happens that would be what we like to call a 'less desirable mode of failure'. Better to have the links at the chain plates fail first and loose the rig than to lose the rig and have it take the cabin top with it IMHO (and others too).
Given all that it may not be possible to design the rig so as to eliminate fatigue failure.
Had to chime in on this....for anyone not to replace rigging every 10 years is crazy, its be proved time after time that you can’t tell by look at it if rigging is good, and it’s not the riggers it’s the wire and fitting manufactures who tell us to replace every 10 years as they test the product continually and do destruction testing. Can you tell if a piston is going bad by looking at the engine? Rigging is the most important part of any sailboat but gets the least attention. Run your car on the same tires for 10 years and see what happens....Do the right thing, as old rigging is false economy...Check out this article.
http://dixielandmarine.com/yachts/DLrigprob.html
Smooth AND SAFE sailing to you all.
http://dixielandmarine.com/yachts/DLrigprob.html
Smooth AND SAFE sailing to you all.
Its absolutely amazing that in countries with 'an abundance of lawyers problem' that rigging is promoted to be changed out every ten years.
In countries where lawyers/litigation is restrained, such rigging lasts a lot longer and the change out is based on 'science' rather than 'risk and casualty pay out'.
In countries where lawyers/litigation is restrained, such rigging lasts a lot longer and the change out is based on 'science' rather than 'risk and casualty pay out'.
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