chainplates

[robwilk37]

I once removed/replaced the glassed-in chains on a buddies boat. a real head scratcher til we realized they where T-shaped at the bottom. tons of gritty and dusty work, lots of cabinetry demo, all in all a miserable job. we replaced them with externals. that was 20 years ago.

today I wouldn't hesitate to replace with composite chainplates. if you've got the demo done then most of the "prep" work will also be done. composite chains eliminate corrosion concerns, eliminate deck leaks, aren't terribly difficult to fab up, can be hugely over built for little extra money (safety factors of 10 or more) and do a better job of distributing load paths. for me, the last thing I want on my mind when the weather turns is whats holding up the stick.

of course the universal caveat is you can do all the work yourself and take your time to do it right. if you've got to hire a composites fabricator to knock them out then you better have Larrys money.

my .02

[HappyMdRSailor]

Originally Posted by Jim Cate

Yes, but with external plates one can visually detect developing cracks before they reach failure level.

But, for many designs, having the chainplates outboard will have detrimental effects on windward performance, increase chafe issues, and look kinda agricultural (IMO).
Cheers,

Jim

HA!

Jim... You mean like on a Moooooorgan?

I actually think that experience driving a team of oxen would be a direct crossover for these babies...

(I crack me up... again...)

Originally Posted by Cheechako

I would remove the core from the inside and build up solid glass where the chainplates are.

+1

Originally Posted by a64pilot

Even if it weren't for the water intrusion issue, how tight can you tighten the bolts before the laminate begins to crush if there is a core?

Originally Posted by sardinebreath

Thanks for all that, guys. Never occurred to me to just replace the core in that area with solid glass. Seems like that would avoid both potential water intrusion and compressing the hull/core when tightening. Read somewhere that chainplate bolts should optimally be tightened to around 20% of breaking strength. That would be some scary compression on a cored hull.

No doubt huh?

Something to be said about the difference in a few 1/2-5/8" fasteners vs 8-10 5/16" though... Albeit... chainplates resembling civil war iron cladding might not be the most aesthetic...

There is the enhanced radar profile though...

Originally Posted by robwilk37

I once removed/replaced the glassed-in chains on a buddies boat. a real head scratcher til we realized they where T-shaped at the bottom. tons of gritty and dusty work, lots of cabinetry demo, all in all a miserable job. we replaced them with externals. that was 20 years ago.

today I wouldn't hesitate to replace with composite chainplates. if you've got the demo done then most of the "prep" work will also be done. composite chains eliminate corrosion concerns, eliminate deck leaks, aren't terribly difficult to fab up, can be hugely over built for little extra money (safety factors of 10 or more) and do a better job of distributing load paths. for me, the last thing I want on my mind when the weather turns is whats holding up the stick.

of course the universal caveat is you can do all the work yourself and take your time to do it right. if you've got to hire a composites fabricator to knock them out then you better have Larrys money.

my .02

Man....
I think composite chainplates are going to be a HUGE game changer in the very near future...

[Stumble]

The one issue with composite chainplates is that the designs I have seen can not be retrofitted. The roving needs to be laminated inside the hull layers to make them a structual part of the boat. Not that in new builds they should be the standard even now.

[Terra Nova]

Originally Posted by sardinebreath

How problematic is throughbolting...through an airex cored hull?...

You just don't! You must make hard spots for through-bolting.

[robwilk37]

not at all. the laminate over the pin is pretty straight forward, then having the surface area to fan-out the tails inside and out, or both sides of a bulkhead is where you need to pay attention. knowing the shear strength of your resin (epoxy) is a good idea. of course you see a lot of new builds, especially cats and race boats incorporating them, but my point was if you've done the demo necessary to extract imbedded chains you've likely exposed and grinder profiled a big enough area already to accommodate composite chains. several guys available on line to spec out a procedure and scantlings. no need for carbon either, e-glass would fine.

finishing up the new cabin top and moving on to my own composite chains project in a couple of months, item 207 on a list of 800 'to-dos'