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Chain plate a go-go


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#1 El Mariachi

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Posted 05 November 2010 - 04:05 AM

Just pulled into San Jose del Cabo's marina with the new owner of our '84 Irwin 52. 'Twas blowing 28 on the nose today on the west side, and we popped the upper 5" of the port aft lower chain plate (attaches behind the lower spreader). Bitchin, given that only 2 inches of it is exposed, above the cap rail. And this was without the sails up. Anyways the new owner wants to band aid it somehow and carry on to La Paz, about 150 miles up the Sea of Cortez. Where it can get real fugly. And real fast. I, on the other hand, have told him that I'm not gonna do that leg, and suggested to him that he should pull the boat out right next door at the new yard and fly in some rigging rok-starz to x-ray the other 7 chain plates and check for additional shitty-ness---(even though the boat was given a clean bill of health last June by the surveyor)....despite the fact that they've been encapsulated in fiberglass and saltwater for the past 26 years. My biggest fear is that the other plates are also on their last legs, and it won't take much to drop the stick. Like dominos. I don't wanna get hurt, the Nurse and the Nursetta don't want me to get hurt and I definitely don't want the new owner to get hurt or punch the hull with the stick------or worse.

Anyways Kidz, I need some ideas of which course of action to steer the new owner to---without scaring the financial dogshit out of him, killing his dream of sailing forever or pushing him off the cliff of suicide 'cuz he bit off more boat than he could chew and is pretty much both depressed and flat broke this evening. It's really pretty f'ng sad to see this happen to him right now, so I'm gonna try my damnest to help him out.


Gracias,

E.M.

#2 Ncik

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Posted 05 November 2010 - 05:08 AM

Test load it? Dunno how but atleast you'll know if they're sound. Maybe some kind of jig on the deck and pull it to over max load...grasping at straws here though...

Inspection and/or replacement is the safe answer.

#3 Moonduster

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Posted 05 November 2010 - 07:26 AM

I wouldn't attempt the trip to La Paz with the boat in that condition.

Go to Puerta Vallarta and have the rig pulled. Then, remove all the chain plates and get detailed measurements of the materials required to make new chain plates. It's quite likely that they are all made from the same basic material - probably 2" x 1/2" stainless stock.

I'd get that material in the USA - not Mexico. The problem here is that if you get lousy stainless, you'll just be screwed again in no time.

Once you have the material, chop it into appropriate lengths and stick it in a suitcase and fly back to Mexico. Find a good metal shop and have them fabricate the chainplates.

It's not an inexpensive job. I'd guess you're going to pay about a grand to have the mast pulled and re-stepped plus another $500 or so per chain plate by the time you're done. But then, I haven't been in Mexico for 4 years now ...

What ever you do - don't go to La Paz - that upwind trip easily has the potential to cost you the rig. Even Mazatlan, a long reach on port, isn't a good idea with a missing port-side aft lower.

Good luck!

#4 WarBird

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Posted 05 November 2010 - 11:54 AM

Quick and dirty is new chainplates outside the rail. Of course verify the backing structure, use toggles to make up the length difference, do one at a time and the rig stays up.

#5 gkny

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Posted 05 November 2010 - 12:40 PM

LaPaz used to be much more cruiser friendly and cheaper than PV. Why not motor to LaPaz. Can't halyard be attached to the toe rail or backing plates be added to provide some temporary support? I would talk to some of the local cruisers or get on one of the cruising nets to ask what yards are good.

#6 bammiller

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Posted 05 November 2010 - 01:29 PM

You think he is depressed because 1 chain plate pulled out; wait until the mast goes over the side. Things happen for reason, and my thought is if 1 chain plate failed the others aren't far behind. And the insurance company will probably not pay the claim, citing preventative maintenance.

I am curious about how a chain plate will only pull partially out of the deck.

Bam Miller

#7 SailRacer

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Posted 05 November 2010 - 01:45 PM

Working on one at a time might make the new owner feel better as the rig is not down and boat could be moved if needed. Chances are the one that came out was 'flexing' the most due to windage of the radar and seaway encountered.

IMHO Get halyards into position and start making plans on making new chainplates from US stock - Good luck
Sail safe!

#8 Innocent Bystander

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Posted 05 November 2010 - 01:58 PM

Any chance of getting a look at chainplate attachment without destroying the interior? From some yachtworld photos, it looks like the 3 chainplates/side go through the caprail and into the bulwarK. I would assume they tie into a knee or other structure below deck. By "Popping the top 5 inches" are you saying the chainplate fractured 5" from the top or about 3 inches below deck (and right in the modle of the bulwark)?

I have to agree with the others. Break one. Change all. You can do it with the rig up if you do them one or two at a time.

#9 FastRobert

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Posted 05 November 2010 - 02:41 PM

If you decide on the PV routing,....... a few options and contacts:

1) PV Sailing - the local North Sails loft and rigging 329-295-4065 mex, Attn Mike

2) SYS Rigging and Yacht services -322-145-8194, Attn Jorge

Best Wishes.

#10 longy

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Posted 05 November 2010 - 04:12 PM

Pictures! Many builders would layer two thin pieces of ss plate together to make up thickness needed, led to crevice corrosion between the two. Look into the clevis pin hole, you can see the joint if yours are sandwich construction. Corrosion of the ss plate as it passes thru deck level is also common. Also check bolts for corrosion.
I replaced all chainplates on a Shannon 50 ketch a couple of years ago, after finding a failing chainplate. All had cracks, all had corroded bolts, some had the holes thru the knees elongating. This was causes by use of fully threaded bolts, the thread actually cut thru the knees. Should have smooth bolt shank entirely thru knees. New chainplates were made from solid stock, all new (correct length) bolts, bolt hole pattern offset as needed to skip old worn holes.
The hardest part of the job was getting access to all the chainplates & pulling them up out of the deck.
In your situation: aft lowers undergo more shock loading than all the other chainplates as mast pumps. I would remove & inspect the other aft lower chainplate. Inspect the others as much as possible in situ. Bright lighting will show any cracking as it will have rust inside. If entire surface is dirty, clean it off with a scotch brite pad. The rust down in the crack will remain & be visible. I would leave the stick up, do chainplates in pairs. The added cost & damage possible to rig lying on ground far outweigh the additional time required by doing two at a time. You also need the halyards/winches to get the plates out of the deck.

#11 El Mariachi

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Posted 05 November 2010 - 04:30 PM

Hey Guyz, thanx for getting back on this so quick. I'm gonna post some pics in a bit of this train-wreck-in-the-making. Trust me, you'll love the failed c/plate----looks like a g-damn half eaten Butterfinger from ancient Egyptian times........

#12 El Mariachi

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Posted 05 November 2010 - 07:57 PM

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#13 El Mariachi

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Posted 05 November 2010 - 07:59 PM

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#14 El Mariachi

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Posted 05 November 2010 - 08:11 PM

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#15 Major Tom

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Posted 05 November 2010 - 08:21 PM

Looking at the value of what is still standing I wouldn't take a chance. Best to do as recommended above and replace all the chain plates. Don't be penny wise and pound foolish.

#16 WarBird

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Posted 05 November 2010 - 08:25 PM

Isn't there somethin' bout buried stainless always rusts with moisture present and no air??? (This is a real question)

#17 longy

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Posted 05 November 2010 - 08:41 PM

Exactly - you've got anoxic corrosion where the chainplate goes thru the glass deck. Since the plate had already failed/cracked completely across before leaving the deck (there is NO bright metal showing in pics) I have no faith in the other plates. Do some careful measuring - it might be possible to cut away the teak around the chainplate about 1" all around and see where the failure occured. Put in a teak dutchman to fill hole later. Good timing on the sale!

#18 WarBird

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Posted 05 November 2010 - 09:12 PM

Gunwhale mounted chainplates won't have that problem, are easy to install given proper backing and won't really impact the sheeting angle (already wide). The job looks expensive but really shouldn't be to bad as new plates will be real near the structure the old ones were mounted in (that seems to be the bulwarks by the pictures).

#19 TheFlash

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Posted 05 November 2010 - 09:18 PM

Isn't there somethin' bout buried stainless always rusts with moisture present and no air??? (This is a real question)


Yep - IIRC, stainless requires the presence of oxygen to create an oxide layer on it's surface, which prevents further oxidation. Let it sit in stagnant water, it'll corrode.

#20 Timo42

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Posted 05 November 2010 - 10:21 PM

Online metals has the stainless, have them cut it to length and all the yard will have to do is round off the corners and drill the holes.

#21 Ishmael

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Posted 05 November 2010 - 11:07 PM

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That black bit of teak doesn't look promising...I'd be nervous.

Not my $, but I'd do them all as soon as possible.

#22 El Mariachi

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Posted 06 November 2010 - 12:16 AM





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That black bit of teak doesn't look promising...I'd be nervous.

Not my $, but I'd do them all as soon as possible.


Yup, agreed. And it only took me 14 fricken hours to finally convince him of that.

Now then, that said, here's his latest plan-----Gene Gammon sent him some pics of another I52 that had the same problems. His idea/solution? let off the turnbuckles, Sawzall off the tops of all 8 chain plates, make eight new ones that will go on the outside of the hull (after chopping the dogshit out of both the rub rails and cap rails), mark the holes of the new ones and drill straight thru the hull and the existing ones, put on 8 appropriate sized backing plates on the inside of the hull at all 8 areas, and then bolt the hell out the whole shebang. I'm still not too sure about this entire procedure myself, but I'd love to hear your thoughts. Oh yeah, fwiw, the work will be done by the boat yard next door. At least they have a sister yard in San Diego, so they can't be all that bad. I hope. And they bill at just $70.00 US per hour----plus materials. Regardless, this sailing adventure is now officially over. Back to Hell-A tomorrow afternoon.........

#23 El Mariachi

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Posted 06 November 2010 - 12:41 AM

An here's some lite reading for any of you interested in invisible chain plates.........



http://www.irwinyach...Chainplates.pdf

#24 WarBird

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Posted 06 November 2010 - 02:57 PM






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That black bit of teak doesn't look promising...I'd be nervous.

Not my $, but I'd do them all as soon as possible.


Yup, agreed. And it only took me 14 fricken hours to finally convince him of that.

Now then, that said, here's his latest plan-----Gene Gammon sent him some pics of another I52 that had the same problems. His idea/solution? let off the turnbuckles, Sawzall off the tops of all 8 chain plates, make eight new ones that will go on the outside of the hull (after chopping the dogshit out of both the rub rails and cap rails), mark the holes of the new ones and drill straight thru the hull and the existing ones, put on 8 appropriate sized backing plates on the inside of the hull at all 8 areas, and then bolt the hell out the whole shebang. I'm still not too sure about this entire procedure myself, but I'd love to hear your thoughts. Oh yeah, fwiw, the work will be done by the boat yard next door. At least they have a sister yard in San Diego, so they can't be all that bad. I hope. And they bill at just $70.00 US per hour----plus materials. Regardless, this sailing adventure is now officially over. Back to Hell-A tomorrow afternoon.........


Just curious. Is there a problem burying the old chainplates or will the moisture be cooked out and sealed? Will rust continue and swell/fracture the mount area? Is that a 1 year, 10 year or 50 year problem? Guessing the old chainplates aren't being removed(those that don't break).

#25 rob d

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Posted 08 November 2010 - 11:44 AM

Interesting article on the x-rays. I did a bit of non destructive testing on industrial stainless welds to be used at a petrochemical plant. Technically it was Gamma, not that it matters. Bring your lead undies. My first day the guy I was working with handed me a box with a protector cup made of lead and said "Your choice-lead poisoning or gamma"! That "box" it comes is is very heavy! (For the shielding properties) no dropping on the boat. Sure would be much more interesting work than 10km of pipe welds.

#26 memopad

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Posted 08 November 2010 - 12:39 PM

Gamma radiation has higher energy than that of x-rays. Medical devices (CT, x-ray, mammo, etc) produce x-rays using x-ray tubes. Zap some electricity into the tube and blast some electrons out the other end sort of thing. Gamma radiation is usually the result of radiactive decay and is also used medically (nuclear medicine for example). Because of its higher energy special detectors are used (gamma cameras). Both gamma and x-ray are ionizion radiation meaning they interact with tissues of the body, so you shield yourself from both.

So anyway, what you used in your industrial testing was almost certainly x-ray machinery, not gamma.

#27 BalticBandit

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Posted 08 November 2010 - 06:48 PM

Gamma radiation has higher energy than that of x-rays. Medical devices (CT, x-ray, mammo, etc) produce x-rays using x-ray tubes. Zap some electricity into the tube and blast some electrons out the other end sort of thing. Gamma radiation is usually the result of radiactive decay and is also used medically (nuclear medicine for example). Because of its higher energy special detectors are used (gamma cameras). Both gamma and x-ray are ionizion radiation meaning they interact with tissues of the body, so you shield yourself from both.

So anyway, what you used in your industrial testing was almost certainly x-ray machinery, not gamma.

Umm, 'gamma radiation' and 'x-rays' are both high energy photons... historically there has been some differentiation between the two based on the energy levels and means of production but that is no longer true.

#28 memopad

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Posted 09 November 2010 - 02:57 AM


Gamma radiation has higher energy than that of x-rays. Medical devices (CT, x-ray, mammo, etc) produce x-rays using x-ray tubes. Zap some electricity into the tube and blast some electrons out the other end sort of thing. Gamma radiation is usually the result of radiactive decay and is also used medically (nuclear medicine for example). Because of its higher energy special detectors are used (gamma cameras). Both gamma and x-ray are ionizion radiation meaning they interact with tissues of the body, so you shield yourself from both.

So anyway, what you used in your industrial testing was almost certainly x-ray machinery, not gamma.

Umm, 'gamma radiation' and 'x-rays' are both high energy photons... historically there has been some differentiation between the two based on the energy levels and means of production but that is no longer true.


Its all relative eh? Typical gamma energies as i was taught are above 100kev, x-ray generally below 90kev. So by "high" energy i meant higher. I suppose its all semantics, but in the medical field there are gamma cameras, and they are completely different beasts than x-ray equipment.

#29 rob d

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Posted 10 November 2010 - 10:18 AM

Iridium Isotope (pill) deployed down the inside of the tube by a manual cable and handle-like an exploded window winder. Used a Tungsten shield on the tip so we didn't get too much of a dose. Still needed the health dept. tags checked monthly though. Used to be a Cobalt Isotope but Iridium has the shorter half life. No electricity required. Good for remote sites and other than the weight of the transport chamber, quite small and portable.




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