chainplate moving

[brianbarone]

Hi, I have a cascade 36 with old chainplates that are bedded to the hull and glassed over. These things are very difficult to get to and remove, since they are in the lay up of the hull and Cascade suggested that It might be best to cut them off at deck level, glass over them, and move the new chainplates next to them. This had been done successfully in the past with other boats.

My question is first, should I move the new lower chainplates to a wider footing, move them all a little to the stern (I have an adjustable spreader angle since they are attached with Pins), or what. A friend advised if anything to move the uppers back, and widen the lowers which seems to make sense.

The second question is that since the chainplates will be attached directly to the hull, can I attach them inside the boat (its not really a traditional looking boat and I would like to avoid the look of long external chainplates),m or is it best and easiest to just go outside the hull. If so, can I paint the stainless white, or will that accelerate corrosion? I dont have bulkheads that are placed in quite the right place for a direct attachment via an inboard lead.

Thanks,
Brian

[Ian McColgin]

Why are you doing this?

If there is something wrong with the existing chainplates, whatever it is may well affect the hull integrity. Were I a rigger in your boatyard, I'd not answer the question about how until I knew the why.

If you really must go with new chainplates you should go external. The chainplates need to be through-bolted to a nice long ss strip anyway, so there will be something outside the hull. That might as well be the chainplate itself, and save yourself cutting a hole in the deck.

Do you have access on the inside?

I don't know your boat, but there's plenty of production boats where the chainplate comes in through an athwartships slot and is bolted and/or buried in a bulkhead rather than the hull. However done, there may be a ceiling or bit of cabin furniture in your way. Sometimes it's impossible to get a continuous ss strip for the bolts to land in. It can be a bit discontinuous but the more unitary it it, the better load sharing you'll have.

You of course need to know if the hull is cored at that point. If it is, this instantly becomes a more complex job as you'll need to over-bore the bolt holes and makse some non-crushable bushing, which could be as simple as a bit of structural wood.

Anyway, there may be more here than your question reveals.

G'luck

Ian

[brianbarone]

Hi,

Thanks for the quick reply. I would like to replace them, because the chainplates are 35 years old, and are almost completely glassed over so I cannot inspect them. I have also found crevice corrosion in other SS bits of the boat (bobstay attachment tang looked crystallized through repeated loading and almost eaten through at the clevis pin hole) and so I don't trust them anymore. There is a bit of rusty water that seeped from one of them as well. We will be crossing the pacific in a years time and I don't want to have to worry about them

The original plates are somewhat strange. They are attached up against the inside of the hull (not attached to a bulkhead) the plates are ss with litttle rounds of metal welded to them to act as "teeth" facing inboard, presulably to help the glass layers that were mounded over top of them to keep a hold of them. I have chipped the glass from around a few of these "teeth" thinking that I might expose the bolts and take them off to find out that they are not bolts, but short sections of smooth round ss bar welded to the buried plates (weird I know). This is defintely the case, since the bar stock wasn't really corroded at all and is definitely not a bolt rusted away to round. There are also no boltheads outside the hull or any other indication of through bolting either.

So anyway, these suckers are well and glassed in, in some cases in really hard to reach areas (aint it always), and so other owners of the same boat have cut them off flush and replaced them. The manufacturer of the boat is still in business and I e-mailed tham and this is what they suggested also. Other boats are reportedly sailing around the world with them in the exact same configuration and have no problms, but you don't have problems till you have problems, and when me and the wife are getting knocked around in 30 foot seas, I really want one less thing to focus on stressing about.

The rest of the boat is built quite strong, with a massive beam running its way all around the boat at the hull to deck joint. Some of the other cascades had their rigging attached to the toerail, which was through bolted to this big beam. Seems the chainplates are the weak link on the design.

As far as the moving them inboard, I think you are probably right, It should be easier stronger and less leaky to just bolt em on outside. Any pointing advantage I was hoping for can probably be gotten through running the jib sheet lead to a track inboard and just leading the #3 jib inside the shrouds.

Movement necessary fore or aft would probably be just be enough to clear the old plates. The hull is solid glass, and cascade 36s were designed for circumnavigation, so the hull lay up is reported to be quite thick and strong. So then, the question is which way can they be moved without mucking with the rig loads in a bad way?

Sorry this was such a long one. I hope I am not missing something

Thanks,
Brian

[Ian McColgin]

The bobstay attachment may be suffering from air/water induced electrolysis, just as the copper anti-fouling paint, copper sheathing and many metal boats go faster at the waterline. SS is not very active and has a far longer life than copper. You can test this yourself with a sensitive meter clipped to two ends of a copper bar. Keep one end dry and the other wet in salt water, but move the bar up and down. You'll get a bit of voltage.

Anyway, boats move around enough that I can't see how moving everything aft in order, as close to original as possible, will do any harm, unless you already tune to a foreward rake and want to take that out.

I take it that whatever is happening with rusty water can be fully drained and made to not cause more water intrusion and hull delamination.

G'luck.

Ian