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#21
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Did you know this?;
"Simple Simon" wrote in message ... One gets rid of wooden junk after that many years. It should have been replaced with an aluminum spar long ago. Wooden spars, like standing rigging don't last forever. To be safe replace wooden spars every ten to fifteen years. |
#22
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Simple Simon wrote:
and My responses to his Comments interspersed. As required "matt colie" wrote in message ... Please do tell us -Oh (self ascribed) Great One A. How can a mortal human determine that tubular spreader that has been adequate to the purpose for eleven seasons is about to buckle in a long column type failure when the conditions had lightened in the last two hours? Are you sure the spreader tube was the cause? I doubt it myself. Not being there I'm just guessing but I'd find it hard to believe there could be enough stress on the spreader to break it if there were not something else that let loose first. =Most of the rig was still aboard, we were able to recover the upper mast, the genoa, head and back stays from the shallow water as we had tied a cushion to a spinnaker halyard. Nothing was broken or loose. The failed spreader was a picture of classic long column buckling failure. Why it chose then, we could not determine. B. How (thirty-plus years ago - no portable ultrasonic inspection available) does one assess the soundness of a twenty year old formaldehyde-resorcinol joint that was closely examined as the owner had sanded and varnished the spar three weeks before that day?? One gets rid of wooden junk after that many years. It should have been replaced with an aluminum spar long ago. Wooden spars, like standing rigging don't last forever. To be safe replace wooden spars every ten to fifteen years. =There are a whole lot of people that disagree with you here. If this is actually your opinion, I suggest very strongly that you not voice it in the hearing of any of the conservators of classic boats and yachts. There are a goodly number of built-up section masts that are still in service and I know for a fact that the owner’s don’t share your opinion about this. I’m going to have a thirty five year old mast in my shop this winter so the owner can refinish it. Even the early larger glass boat were often delivered with wood spars as extruded section of adequate size were not yet available. C. How does a common citizen determine that there is an invisible crack at the bottom of a finishing mark that has caused fatigue embrittlement to an otherwise nice looking 316 stainless strap? There are dyes available for this purpose. =Dye penetrants are very difficult to evaluate on surfaces that are not smooth. Penetrants will not reliably indicate a discontinuity as small as the instigator probably was (based on the surviving parts) How does a dye detect an embrittlement. This is a change of the materials physical properties and was only detected by microscopic evaluation and microprobing the local hardness of the sectioned and polished parts. This boat's chainplates were later inspected by a professor of metallurgy in his lab at a near-by well known university. I quote “We didn’t stand a chance.” The professor had been on the helm at the time and was the person injured. You should have checked them more closely before they failed. Maybe if you had removed them and sent them to the same lab prior to the time they failed you could have gotten the news in time to do something about it before the failure. =The analysis that finally gave the definitive answer was destructive. (No - eddy current was not conclusive either.) The cost of the analysis (if billed at the labs standard rates) would have been in excess of 1000$us in 1975 dollars, but as it was the helmsman’s lab.... (Hey - the guy got his arm busted - he wanted to know why.) You are not totally to blame because the chainplates were not made thick enough to begin with or they would not have fatigued and failed. That should be a little consolation to you.My chainplates are 3/16" thick and 1-3/4" wide. They are as strong as the day they were installed. You could lift the whole boat with them. S.Simon =Most of the 3 and 400 series stainlesses are relatively fatigue prone. That is why standing rigging has a limited life. =Have you removed said chainplates for proper inspection? =This was a 40 foot boat, and the chainplates were 3/8 thick and about 2" wide. The replacements were made with a polished surface even though this makes them more susceptible to face wear by the turnbuckles. Matt Colie - See prior sig |
#23
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Ganz, I can't see your post on my newsreader,
so I answer to this post instead, after reading your post on google: This is not meant as criticism, but why did you call the coastguard ? Was that necessary ? A few month back I was on a boat that lost the mast and we decided that we had to cut it loose to avoid damage to the hull. But I wonder if we could have salvaged the rig. Had we cut all but the wires, halyards and sheets except for the aft stay, the boat would have been blown to leeward of the rigging and it might have been safe to start the engine and pull the rigging in to sheltered water where it might have been possible to drop the anchor and get some of the gear onboard. Since the sails were damaged, the mast broken and most or all of the standing rigging would have to be changed anyway, I don't think we could have saved a lot of money, but anyway, I wonder if it would have been possible. And ... an experience like that really makes you remember always to keep a well dimensioned wirecutter onboard. |
#24
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Umm not sure what you mean by some of this...
oh.. having some newsreader problems... ok. 1st... I wasn't on the boat, but calling the CG was prudent, given that the boat was in a major shipping channel. The CG likes to know these things so that they can 1) alert inbound and outbound traffic 2) come and help if necessary, but mainly stand on in case things get worse.. e.g., mast penetrating the hull. Personally, I'm glad that the skipper cut everything loose, rather than try to retrieve it. The stuff wouldn't have been worth much and it would have been dangerous, given the conditions. "Aniculapeter" wrote in message k... Ganz, I can't see your post on my newsreader, so I answer to this post instead, after reading your post on google: This is not meant as criticism, but why did you call the coastguard ? Was that necessary ? A few month back I was on a boat that lost the mast and we decided that we had to cut it loose to avoid damage to the hull. But I wonder if we could have salvaged the rig. Had we cut all but the wires, halyards and sheets except for the aft stay, the boat would have been blown to leeward of the rigging and it might have been safe to start the engine and pull the rigging in to sheltered water where it might have been possible to drop the anchor and get some of the gear onboard. Since the sails were damaged, the mast broken and most or all of the standing rigging would have to be changed anyway, I don't think we could have saved a lot of money, but anyway, I wonder if it would have been possible. And ... an experience like that really makes you remember always to keep a well dimensioned wirecutter onboard. |