Chainplate bolts: OK?

[Stumble]

Originally Posted by Orion Jim

Is there some reason why silicon bronze is not being considered? It would have been my first choice.

Other than being expensive a heavy? Cast bronze which makes up a huge percentage of available bronze is unsuited for tensile applications. At least unless it has been HIPPed and density tested, which really isn't done commercially. Forged bronze is a perfectly reasonable option.

C655 forged bronze is pretty much a size for size replacement for 316 stainless but no 304. It can be MIG welded, and is acceptably ductile to bend to match the hull curve. It also gets a green patina which can be either lovely or ugly depending on your preferences.

Last time I looked C655 was about the same price as G2 titanium. So it may really come down to the machine shop you choose to use.

[UNCIVILIZED]

Originally Posted by wesley

Whoops, yes, I should have been more clear. That's exactly right - there is nothing on the outside of the hull, everything is interior or embedded in the glass.

-W

In that case, you really, really need to start over. Meaning rip out everything, especially the embeded plates. Then rebuild the hull. Followed by redesigning, & building new chainplates & backing plates.

Chainplates encapsulated in fiberglass are notorious for being a bad idea, though many otherwise reputable boats have them. Which about a decade into their service life leaves it to the owners to replace them at massive cost. Island Packets for example.

[wesley]

Originally Posted by UNCIVILIZED

In that case, you really, really need to start over. Meaning rip out everything, especially the embeded plates. Then rebuild the hull. Followed by redesigning, & building new chainplates & backing plates.

Chainplates encapsulated in fiberglass are notorious for being a bad idea, though many otherwise reputable boats have them. Which about a decade into their service life leaves it to the owners to replace them at massive cost. Island Packets for example.

Oh! Well, that sucks.

[Copacabana]

Originally Posted by UNCIVILIZED

In that case, you really, really need to start over. Meaning rip out everything, especially the embeded plates. Then rebuild the hull. Followed by redesigning, & building new chainplates & backing plates.

Chainplates encapsulated in fiberglass are notorious for being a bad idea, though many otherwise reputable boats have them. Which about a decade into their service life leaves it to the owners to replace them at massive cost. Island Packets for example.

It may be possible to leave the plates in the hull as they are, drill the bolt holes through to the outside of the hull and then put external plates on the outside of the hull. In this case I would still add some sort of backing plate on the inside as well.

[UNCIVILIZED]

Originally Posted by Copacabana

It may be possible to leave the plates in the hull as they are, drill the bolt holes through to the outside of the hull and then put external plates on the outside of the hull. In this case I would still add some sort of backing plate on the inside as well.

My concern with the above, or any variation on it, is that as steel corrodes it can increase in volume several fold. Which would play havoc with the laminate on either side of it. Thus my comment about taking the plates out. As even stainless corrodes. So unless they're either bronze, or titanium...
And even then, they form a pocket whereby water may get into the layers of the laminate, sight unseen. Going unnoticed until a truly expensive fix is needed. Such as if a small amount of water in such a pocket froze in the winter time & explanded.

[Copacabana]

Yes, ideally one would cut out the embedded plates and replace/beef up with glass before fixing the external chain plates and backing plates. It shouldn't be too big of a job and will certainly result in a simpler, more easily-inspected rig.

[Suijin]

Originally Posted by Stumble

No idea of current prices, but a few years ago I was quoting G2 Titanium plates pretty regularly. Our prices probably averages about 20% more than 316L plates.

Not so long ago when talking about machining the adage was material is expensive and labor is cheap. It's flipped around the other way.

I suspect the fabrication cost is going to vary widely depending on the shop you go to and their experience working titanium. If you go through a rigging shop that does the work themselves, your costs are going to be significantly higher than if you go to a dedicated machine shop. In fact, the preeminent rigger in Annapolis, who does a ton of work on high-end race boats, will tell you right to your face that if you don't want something specialized there is a machine shop in Baltimore that will do the work far more economically. In other words, YMMV depending on where you are and who you call.

I spoke to the guy who's going to make my chainplates yesterday and asked him about titanium. He has some experience with it, from working on race boats, and confirmed that the fab cost would be considerably higher. But that's just him. He smirked and said "You'll be dead by the time a new set of 316's need replacement." While I'd like to think his estimate of my lifespan is a tad off, he has a good point.

All that said, Stumble do you have contact info for that shop that was making those titanium plates? If they can do the work for 20% more than the cost of what I've been quoted, I'd be all over that. I could send them photos and specs of the plates for a quote, and then ship them the old ones and they'd have at least a month for turnaround.

[Suijin]

Originally Posted by Copacabana

It may be possible to leave the plates in the hull as they are, drill the bolt holes through to the outside of the hull and then put external plates on the outside of the hull. In this case I would still add some sort of backing plate on the inside as well.

I think that would probably end up being more work, more expensive, and a less robust solution in the long run. The glass work involved in restoring the current install on the Nicholson is pretty rudimentary. And the existing design lasted 35 years. It did not deteriorate because of the design, it deteriorated from poor maintenance. If you don't keep the deck seal on your SS chainplates in good repair they are almost certainly going to need replacement before they need it from exceeding their cycle life.

[Copacabana]

Originally Posted by Suijin

I think that would probably end up being more work, more expensive, and a less robust solution in the long run. The glass work involved in restoring the current install on the Nicholson is pretty rudimentary. And the existing design lasted 35 years. It did not deteriorate because of the design, it deteriorated from poor maintenance. If you don't keep the deck seal on your SS chainplates in good repair they are almost certainly going to need replacement before they need it from exceeding their cycle life.

I think the external chainplates would be far more "robust" and it does eliminate the problem of water ingress at the chainplates. The embedded chainplates may have been adequately robust, but if you stop and think about it, the rig is trying to pull those steel plates up through the fiberglass (shearing the laminate). External chainplates are pretty much bulletproof and solve a lot of problems like strength, leaking and problems with inspections. From the OP's photos it seems the shrouds are pretty much outboard anyway, so moving them to external chainplates won't make much of a difference on sheeting angles.

[Suijin]

Originally Posted by Copacabana

I think the external chainplates would be far more "robust" and it does eliminate the problem of water ingress at the chainplates. The embedded chainplates may have been adequately robust, but if you stop and think about it, the rig is trying to pull those steel plates up through the fiberglass (shearing the laminate). External chainplates are pretty much bulletproof and solve a lot of problems like strength, leaking and problems with inspections. From the OP's photos it seems the shrouds are pretty much outboard anyway, so moving them to external chainplates won't make much of a difference on sheeting angles.

1. You have to drill holes through the hull
2. You still need to inspect them as corrosion can start from where they are sealed against the hull.
3. They'll be more expensive than replacing his existing ones, since they are a new design and need to be curved to the hull form
4. You still have to remove and reglass the area where they old ones were, and then deal with the holes in the deck.
5. They will look like sh!t.
6. No need to "stop and think about it". He doesn't need more robust. The old one's lasted 35 years. His problem is not from the forces on them, it was from corrosion.

[Copacabana]

Originally Posted by Suijin

1. You have to drill holes through the hull
2. You still need to inspect them as corrosion can start from where they are sealed against the hull.
3. They'll be more expensive than replacing his existing ones, since they are a new design and need to be curved to the hull form
4. You still have to remove and reglass the area where they old ones were, and then deal with the holes in the deck.
5. They will look like sh!t.
6. No need to "stop and think about it". He doesn't need more robust. The old one's lasted 35 years. His problem is not from the forces on them, it was from corrosion.

1) No big deal. It's a quick job.
2) Much easier to inspect. Nothing hidden. You can easily remove them (one at a time) to see the underside if you think there is some corrosion going on. Not likely without showing signs.
3) They are cheap to make (SS flatbar) and you'll have to make new embedded plates anyway.
4) Yes, but that is going to happen anyway.
5) A matter of opinion I suppose, but I think they look pretty shippy on the right kind of boat.
6) There are many things on ANY boat that can be improved on. Chainplates are a good example.

Anyway, I was just putting out the option for the OP. I'm sure if he buys the boat he'll decide for himself what course to take. I made the comments about external chain plates because that is exactly what I did on my boat and I have no regrets.

[Stumble]

Originally Posted by Suijin

Not so long ago when talking about machining the adage was material is expensive and labor is cheap. It's flipped around the other way.

I suspect the fabrication cost is going to vary widely depending on the shop you go to and their experience working titanium. If you go through a rigging shop that does the work themselves, your costs are going to be significantly higher than if you go to a dedicated machine shop. In fact, the preeminent rigger in Annapolis, who does a ton of work on high-end race boats, will tell you right to your face that if you don't want something specialized there is a machine shop in Baltimore that will do the work far more economically. In other words, YMMV depending on where you are and who you call.

I spoke to the guy who's going to make my chainplates yesterday and asked him about titanium. He has some experience with it, from working on race boats, and confirmed that the fab cost would be considerably higher. But that's just him. He smirked and said "You'll be dead by the time a new set of 316's need replacement." While I'd like to think his estimate of my lifespan is a tad off, he has a good point.

All that said, Stumble do you have contact info for that shop that was making those titanium plates? If they can do the work for 20% more than the cost of what I've been quoted, I'd be all over that. I could send them photos and specs of the plates for a quote, and then ship them the old ones and they'd have at least a month for turnaround.

Allied Titanium is who I worked for, and would recommend though I have no further financial interest with them. They are a titanium fan shop only, and their machinists only do titanium work.

On badly designed chainplate systems I have seen the most replaced in less than five years. So unless you are critically ill it just depends on the design. Encapsulated plates with a deck penetration are almost catagorically a terribly idea, there may be a way to do it well, but I haven't seen it.

[a64pilot]

Allied only makes plates from grade 5 now, which is what I would use anyway. We looked it up at work and assuming 304 was in its half hard state it takes 6/4 or grade 5 Ti to meet its strength, wild card is not knowing heat treat level of the Ti.
I am having a set of chainplates sent to Allied for a quote, I expect based on their other pricing to be twice as expensive as 316L from Garhauer.
However the labor is so expensive to have mine replaced I will likely go that route if it's only twice as expensive.

[Rhapsody-NS27]

First, I agree with cutting them out and replacing. That's an accident waiting to happen.

Originally Posted by a64pilot

Allied only makes plates from grade 5 now, which is what I would use anyway. We looked it up at work and assuming 304 was in its half hard state it takes 6/4 or grade 5 Ti to meet its strength, wild card is not knowing heat treat level of the Ti.
I am having a set of chainplates sent to Allied for a quote, I expect based on their other pricing to be twice as expensive as 316L from Garhauer.
However the labor is so expensive to have mine replaced I will likely go that route if it's only twice as expensive.

I had 9 chainplates made by Garhauer that cost me in the mid $500s. They came out pretty nice and happy with them.

[Stumble]

Originally Posted by a64pilot

Allied only makes plates from grade 5 now, which is what I would use anyway. We looked it up at work and assuming 304 was in its half hard state it takes 6/4 or grade 5 Ti to meet its strength, wild card is not knowing heat treat level of the Ti.
I am having a set of chainplates sent to Allied for a quote, I expect based on their other pricing to be twice as expensive as 316L from Garhauer.
However the labor is so expensive to have mine replaced I will likely go that route if it's only twice as expensive.

Size for size with G5 is obviously going to be a massive increase in UYS, but there isn't much downside. While the UTS with G2 is lower, because you don't need a corrosion allowance the engineers I talked to were fine with it. But if there is any question, certainly G5 eliminates any concerns.

I am pretty sure the standard G5 was ASM 4911, but it has been to long to be sure. I know I never dealt with an order that asked for a specific heat treatment it was exclusively just mill stock, cast, or HIPPed parts.