Source for replacement chainplates?

[pbryant]

Does anyone have a source for Ariel chainplates for the shrouds? I'd much prefer bronze, but will settle for stainless: which I'll have to replace frequently (explained below).

I'm hoping to not have to buy raw stock and have them machined. But if I do, I'll upgrade to 1/4 inch thick (3/16 is specified) C954 alloy aluminium bronze, unless someone here voices concerns. I'd like to seal the chainplates at the deck to prevent water intrusion, and applying sealant to stainless steel deprives it of oxygen, reactivates it, and causes rapid corrosion in a salt water environment. (Of course, there's always titanium: $$$.)

Here is an excerpt from an excellent post at http://www.cruisersforum.com/forums/f126/stainless-vs-titanium-chainplates-85335.html that describes the issue with applying sealant to stainless steel:


"As we trace the chainplate through the boat however we hit the first major problem, called the 'blind section, it is the area where the chainplate is penetrating the hull [deck] and is not visible from above or below without removing the chainplate from the boat. Right at the point where the plate enters the cut out to pass through the hull [deck], standard installation guidelines call for bedding the chainplate into the hull [deck] with 4200 or 5200. Immediately we have created a gasket or ring that while water resistant is likely to eventually fail, even if microscopically and allow some water penetration. Once this water has penetrated the salt crystals immediately start to work corroding away the steel."

I've read several posts here describing applying sealant to stainless through-deck chainplates, or mounting stainless external chainplates to the hull sides (where the side against the hull is inevitably deprived of oxygen). That bothers me a lot. Stainless steel + water + salt - oxygen = rapid corrosion. The post cited above describes the process much more thoroughly. My current stainless chainplates look nice and shiny where they are in free airflow, but are rusting at the through-deck seals and bulkhead-facing surfaces below deck (every place I can't normally see - in obeyance with Murphy's Law of Marine Corrosion). If I use stainless, I'll have to plan on replacing them once a year. Bronze (or titanium) doesn't have that problem.

[ebb]

copper penny's worth:
Years ago I bought 1/4" silicon bronze plate from Metal Service Center in Windsor CA.
707.838.8088, numbers may have changed. Recently a Triton owner got some bronze
from them...it ain't cheap.
I had it cut to width I thought I wanted: 1 3/4".

[I moved littlegull's plates to the outside of the hull, and made them twice as long.]

If you have your originals still installed, and want to keep them there, you'll notice it has
three bolts in the stubby plywood knees that hold the lowers. The top bolt goes through
nothing at the top of the bulkheads.
My pieces were rotten on top. Essentially the short bronze plate had one working fastener
for each plate. Not only that, but the rigging's tension on the plate is at an angle. Problem.
I think a much longer plate is needed to add a real third bolt at least 2" down from the top
of the plywood.
Since original chainplate knees are only tabbed to the hull, I sistered in another piece,
doubling the thickness. Created more substantial tabbing to the hull, and some over head
in the V-berth.

You may have some balsa core deterioration in the deck. Depending on the extent, it might
be corrected by digging it out and replacing with epoxy and chopped strand or......?

A third decent fastening will also more likely immobilize the chainplate and keep it from ever
moving in its thrudeck position, making it easier to caulk.
Whether you choose butyl or 5200 is a personal choice. Permanent 5200 will eventually
oxidize and shrink and become cracked. (Then what do you do?) While butyl may become
problematic, it's quite possible that the CompassMarine Bed-It butyl will outlast the life of
your boat, it is outrageously tenacious, won't harden, won't degrade in sunlight.

Also believe that the cover plates around thrudeck chainplates often seen on older boats
is good insurance against leakage through the deck at the chainplates. These 'beautyplates'
have their own screws. Maintenance can be done by recaulking these covers when needed.

Aluminum bronze is very strong stuff. Have no experience with it.
My silicon bronze plate, which has grain since it is not cast, is also pretty strong stuff.
Found it relatively easy to jig saw, shape, drill holes, round edges, smooth and shine with
normal blades & files, and papers. Tapered, rounded, edged on a combo table sander.
Al oxide disk and belt.

www.tnfasteners.com/ to find bronze bolts and fasteners, Including tre`cool strut bolts!
Also known as Top Notch Fasteners. They have the best selection anywhere.

MaineSail CompassMarine has an encyclopedic photo essay on installing metal fittings on
our fiberglass boats. Worth a looksee.

Have fun!:D

[pbryant]

Thanks Ebb! It's always good to hear from you!

Since I don't like the idea of applying sealant to stainless, I got quotes for a machine shop to fabricate C954 bronze plates, and out of curiosity, another to fabricate them from titanium. The cost of materials plus labor for C954 bronze is about $100 per plate. The quote from Allied Titanium to fabricate the plates from 6mm (0.236 inch) Grade 5 (Ti-6Al-4V) titanium is $163 per plate. I'm rather astonished that the titanium came in that cheap. Titanium of that thickness is 3 times as strong (tensile strength) as 1/4 inch bronze or 3/16 inch 316 stainless -- and it is inert in seawater -- it will never corrode.

I'd have to go with titanium bolts as well, but still, the strength and longevity of titanium is very attractive. It'll be nice to never have to replace the chainplates, even though the price eats deeply into my beer budget.

I'll have to go out to the boat and have another look at the bulkhead fastenings. I believe I saw three good fastenings through each bulkhead. When I replace the chainplates, I may keep the current stainless plates - that are corroded but still serviceable - and use them as backing plates at the bulkheads. Since the holes are on symmetrical 2 inch centers, I can invert them and use the 4th pin hole as another fastening through the bulkheads.

[ebb]

Original Pearson chainplates were bronze.
Yours must be a dreaded former owner.
You may discover the s.s. plates are longer and
had new holes drilled. May have too many holes.
The original bronze ones were like 6 or 8'' long!!

When you replace with your $600+ chainplates,
you do know why they rusted:
sodium chloride crevice and pitting corrosion.
s.s. means super sick.

Don't really know what alloy the old metal is...
why not find out how far you can toss them!:rolleyes:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Titanium also has a passive oxide film. Wonder if
you deprive it of oxygen at the bury in the deck,
that might produce a similar problem?

[Fritz]

I purchased 7 new ss chainplates from Chainplates Express in Texas - http://chainplatesexpress.com/

They did a great job. However, they do not make 3/16" thick. I ordered 1/4" thick and paid about $560.00 for them. I sent them my old ones and they made the new ones exactly as requested. Good Luck!

[pbryant]

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Titanium also has a passive oxide film. Wonder if
you deprive it of oxygen at the bury in the deck,
that might produce a similar problem?

Like Stainless, titanium does depend on an oxide film. The sources I have found state that its oxide film is superior to stainless:


The oxide film formed on titanium is more protective than that on stainless steel, and it often performs well in media that cause pitting and crevice corrosion in the latter (e.g., seawater, wet chlorine, organic chlorides). (http://www.corrosion-doctors.org/MatSelect/corrtitanium.htm)

It requires very little oxygen to form a film: about 50 parts per million (air is over 200,000 parts per million).

It's used almost exclusively today for metallic medical implants, and we're rather corrosive on the inside. I consider bronze the next-runner-up for corrosion resistance. It corrodes, but very slowly. My bronze rudder shaft lasted 52 years in seawater.

[ebb]

Titanium, still will come to you in an alloy form.
And these days you better know its pedigree.
You'll have to ask the supplier if a bar of titanium
will be happy planted and under constant and
intermittent tension in a fiberglass/composite
at the bury line. (Maybe Sponberg or Kasten can
be asked or Ballenger Spars ??)

Certainly those obviously 304 ss plates performed
textbook corrosion. Don't know the T. metallurgy
or whether bar is extruded or rolled into shape.
Maybe it would be better, for instance, to be in
u-shaped threaded form like some modern 'chain-
plates' or deckplates are. Of course I have no idea.
Just saying that this material might be better
engineered than copying old bronze and iron tradition.

T. might be stronger, but maybe too hard to be
installed at the unfair angle to the riggings tension
on the Ariel....like the more malleable bronze or 300
series chainplates.

The ones you want to replace may not only been
not correct for the installation but also stressed by
unfair tension in the body of the plate
-- especially unprotected at the deck where you have no control --
and at the toggle connect.
IE the metal gets worked!

[pbryant]

I've gotten a quote from Allied Titanium that is comparable to aluminum bronze. I've ordered a set of chainplates fabricated from Class 5 titanium. It's nearly twice as strong in tension as 316 stainless, and I don't have to worry about accelerated corrosion caused by sealants.

Here's a good write-up on sea water service applications of titanium: http://www.uniti-titanium.com/wp-content/uploads/2013/04/Henson-white-paper-seawater.pdf.

[ebb]

Capt: Interesting video Titanium vs S.S. by one Jack Chrysler
filmed by Allied Titanium as an intro to the company.
Looked at some of their products, none of which do they keep in stock.
The video is 8 years old.

Did you wake them up?

Did Jack, who says he's a sitting board member
ever replace any of the rusty stainless on his boat?
Before and After?

Does all their stuff come out of China?

just asking


Read some of that titanium and seawater paper....amazing!

[pbryant]

copper penny's worth:
Years ago I bought 1/4" silicon bronze plate from Metal Service Center in Windsor CA.
707.838.8088, numbers may have changed. Recently a Triton owner got some bronze
from them...it ain't cheap.
I had it cut to width I thought I wanted: 1 3/4".

[I moved littlegull's plates to the outside of the hull, and made them twice as long.]

If you have your originals still installed, and want to keep them there, you'll notice it has
three bolts in the stubby plywood knees that hold the lowers. The top bolt goes through
nothing at the top of the bulkheads.
My pieces were rotten on top. Essentially the short bronze plate had one working fastener
for each plate. Not only that, but the rigging's tension on the plate is at an angle. Problem.
I think a much longer plate is needed to add a real third bolt at least 2" down from the top
of the plywood.
Since original chainplate knees are only tabbed to the hull, I sistered in another piece,
doubling the thickness. Created more substantial tabbing to the hull, and some over head
in the V-berth.

You may have some balsa core deterioration in the deck. Depending on the extent, it might
be corrected by digging it out and replacing with epoxy and chopped strand or......?

A third decent fastening will also more likely immobilize the chainplate and keep it from ever
moving in its thrudeck position, making it easier to caulk.
Whether you choose butyl or 5200 is a personal choice. Permanent 5200 will eventually
oxidize and shrink and become cracked. (Then what do you do?) While butyl may become
problematic, it's quite possible that the CompassMarine Bed-It butyl will outlast the life of
your boat, it is outrageously tenacious, won't harden, won't degrade in sunlight.

Also believe that the cover plates around thrudeck chainplates often seen on older boats
is good insurance against leakage through the deck at the chainplates. These 'beautyplates'
have their own screws. Maintenance can be done by recaulking these covers when needed.

Aluminum bronze is very strong stuff. Have no experience with it.
My silicon bronze plate, which has grain since it is not cast, is also pretty strong stuff.
Found it relatively easy to jig saw, shape, drill holes, round edges, smooth and shine with
normal blades & files, and papers. Tapered, rounded, edged on a combo table sander.
Al oxide disk and belt.

www.tnfasteners.com/ to find bronze bolts and fasteners, Including tre`cool strut bolts!
Also known as Top Notch Fasteners. They have the best selection anywhere.

MaineSail CompassMarine has an encyclopedic photo essay on installing metal fittings on
our fiberglass boats. Worth a looksee.

Have fun!:D

One other use for the buytl tape you reference: I had an annoying leak both port and starboard that would produce about a cup of water per hour when heeled underway. I never found the exact source, but I theorized it was leaks in the hull/deck joint or the rub rail screws. So during haul out, I removed the rub rails, lined the joint with buytl tape to the width of slightly greater than the rub rails, applied the tape to the screws like shown on the CompassMarine site, reinstalled the rub rails, and after tightening the fasteners twice, cut away the excess butyl that oozed out the sides with an extacto knife. I've sailed 300 miles now without a drop of water in the cabin!

[ebb]

pbryant's tip is fabulous!

MaineSail's uber-expensive Bed-It butyl tape would be a great choice here for rebedding
the half-round s.s 'rubrail'. However, Bed-It is so aggressive that I said once it is useless
for anything you ever want to take apart again. Nobody wants to take the s.s rail off
again! Called it "the 5200 of butyl tapes." Would be great in this app. Pity the next guy.

The rail is hollow, should be filled and squeezed tight before the screws are tightened
if using original holes. The Bed-It is 1/2" wide, 1/16" thick, cost $25 for 50ft incl
shipping from Hamilton Marine. 3M has some similar stuff called Black-Buzzardpoop, or
something, at a similar insane price.

Imco, both are superior adhesives, (because that's what these bedding compounds are)
but may not get soft enough to work with easily.
Imco you will not be able to use Bed-It as a casual gasket for threaded fasteners.
The stuff will grab the thread and actual stiffen up so hard you will be unable to turn
the screws, in or out! Experience.


Normal butyl can get too soft. Keep it in an icechest at the boat.
Tremco is a name brand for a really good normal engineered butyl tape. Made for metal
fabricators. It's real sticky too, but in a friendly way! It cost about 1/5 the price for
twice as much. Imco it will work just as well captured under the 1/2 round trim.
If it doesn't, you can take it apart without an act of congress.

Wrapping the screw in butyl is also a capitol idea!!! On a pleasant day the butyl will
be pliable enuf to get squeeze-out with hand pressure, and resetting the screws in
the old holes will go easy and seat waterproof if the screwhead is wrapped in butyl.

Since the stuff never gets hard, you'll know it's always working for you.
Clean-up is an absolute breeze.

[Hull376]

I may have mentioned this before, but I used the cheaper butyl tape on my port lights 5 or 6 years ago after dealing with years of leaks from other products. You can still make nail indents into the butyl where its squeezed between the acrylic and the exterior aluminum frames. No leaks since then, and it will be easy to replace the acrylic when the current ports get crazed and cloudy. Whoever thought silly cone sealant was a good option for this application must be employed by the manufacturers! Boy was it hard to remove silicone before reinstalling with the butyl tape.

[ebb]

Is a thread that also talks about bedding fixtures and failures.

CONTAMINATED GELCOAT*
One of its evils is that silicone can 'throw' an oil that soaks into porous gelcoat
to which nothing ever sticks there again, not even fresh silicone. The oil soaks
into the gelcoat... it's not merely a surface thing. Like the medical profession,
they have given the oil a name: silane. But have no idea what it's doing there!

ButylTape is Really Beautiful

Even so, in my opinion, you go through the motions of cleaning the evil stuff
off with isopropyl alcohol applied with a spray bottle, then, maybe the oil is
now floating on the wet surface of the solvent, use wads of papertowel to grab
and soak up the alcohol without rubbing it in... until dry.

Couple times more to be sure. Spray. 'Grab' the wet stuff off with handfuls of
paper towel. Don't wipe as that may force the oil right back into the surface.
Lightly tooth, scuff, abrade. Remove dust with air or dry brush...

AND I'll bet butyl tape will stick to the surface better than anything else. If
you've chamfered the thru-holes... it'll form a cohesive mass compressed within
the joint surfaces, and alltogether create a good waterproof seal. There is no
known solvent that will suck silicon oil out from contaminated gelcoat. Suggest
a method like this -- which may or may not work -- short of grinding it all off.

Before sanding or scotchbrite, it's possible to check how clean a surface is with
another spraybottle with clean freshwater. Spray it on the prepped surface.
If it sheets and the water runs free, doesn't bead up, it's ready**.
This probably will work, not only for bedding and caulking, but to get a primer
to stick when painting. Of course, if the surface is badly contaminated, you may
never get water-run-free.
Sanding for tooth, after blotted solvent cleaning, may again pull out oil from a
polluted gelcoat... Go lightly.
**If I get water-run-free, I'd skip abrading and go on to the next step.

No caulk/sealant/adhesive will adhere to an oil degraded surface any better than
any other...no matter what it costs.

Pricey permanent bonding tube rubbers, polyurethane & p.sulfide, cure and get
dry. Arguably not dry, but after they evaporate solvents give up their gooeyness
and their tack. Initial bond may be excellent but the now lifeless passive rubber
will harden with age. They do not like high temperature and fail under metal
fittings like stanchion bases and develop leaks. EPDM, the black rubber used
for exposed channels and sealing strips on vehicle windscreens & doors and
butyl tape are considered weather resistant rubbers. P.urethane & p.sulfide
have other attributes -- but UV & heat resistance are not high on the list.

Removable butyl tape, the way it is, it is already cured.
Always wet, arguably not wet, but it always stays sticky, unaffected by UV, and
arguably does not fail. High end crosslinked butyl tape now comes in two
recognizable forms. Tremco 440 100% solids, no solvent, 158F, fairly priced
professional grade b.t. that will allow reasonable disassembly.

Not Always Butyful
3M Weatherban (black) and MaineSails Bed-It (gray) are overpriced mega
aggressive butyl tapes. Imco they do not allow easy removal or take-apart. The
rubber cannot get onto fastener threads, into fastener holes, or chamfers as the
material when turned will stretch and suddenly stiffen, locking the fastening from
further movement, in or out of an assembly. Screws & nuts will suddenly lock,
stop turning. Surfaces resist prying apart so aggressively, they are virtually
impossible to separate. These products should come with a warning.

Imco these super aggressive butyltapes (like 5200 polyurethane) have limited
use on a boat.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*For others discussing the silicone problem, see the forum
Cleaning Silicone Contaminated Parts -- Finishing
www.finishing.com (sorry, you have to type that into google search)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

"Good luck is a residue of preparation." Jack Youngblood