Island Packet Chainplate Replacement

[model 10]

Our full keel rounds up so sharply, it's easy to get the genoa in the water. It's not a knock down by any means though.

[a64pilot]

Originally Posted by Kenomac

Just curious... how come your boat doesn't round up into the wind when you get slammed? Is that due to the full keel? We've been clobbered a few times with fifty knot gusts with full sails up, and our boat rounds up.

She did and I turned into the wind as well and let loose the sheet as much as I dared, once she stood back up the noise from the Genoa was terrible, I was sure it would be shredded, however it survived.
When she went over the Rocna came off the bow but of course was still connected at is tail, it swung around and slammed into the hull and the bang was so loud, I was sure I had lost a chainplate.
It was at night, with zero moon, so really dark. I now tie the anchors roll bars to the railing.
It was a very sudden, sustained gust. She didn't go to 90 degrees of course I'd guess more like 60, but we were standing on the walls of the cockpit, not the floor. She did round up, just gust was so sudden it didn't tight away.
I assume it's like diving an airplane, I can take you out and put you into a 30 degree dive, and first time you will swear we are heading straight down, cause all you can see is ground, but of course we are not.

[a64pilot]

An IP has so much cut away in the front of the keel it's not as full a keel as many.

[SecondBase]

Island Packets enjoy a reputation for high build quality--hard to hear about this Achilles heel. I eyed several longingly at the boat shows.

Glad you figured out a plan to get it back to Bristol condition and good luck [emoji256] with it.

[buckoneil]

Hey Y'all,
This past winter we purchased a 1989 IP 35, hull 007, one owner. He was a good sailor and took really good care of her. The surveyor strongly suggested we replace the standing rigging because it was original. We decided to replace the chainplates at the same time. The yard doing the work fabricated the new plates to match the old ones. I had them save the old plates for me. The first thing was the old plates were just fine. And I was surprised how flimsy they were. They are made of !/4 or 5/16 x 1 flat bar, and look scary light to me. I have some experience with metals and fabrication and wish the yard had let me know the condition of the plates, I would have just put them back in or replaced them with something sturdier. Supposedly, the basic problem is the alloy used for the plates before 1996. It cost a lot to replace those plates. I think I should have asked to see the old ones before having new ones fabbed and installed.

[missourisailor]

hey Buckoneil,
I see that you are from NC. Did you have the chain plates done in NC and if so where?

[missourisailor]

Originally Posted by Frankly

In my opinion most of the load in the original IP design is carried by the cross angle welded and located just under the gunnel. On a pure external bolted chain plate the hull side takes the entire load.

This is exactly what Bill B. from IP told me. The hull was not designed to accept external chain plates. Also, even if you were able to drill through and bolt new plates to the old, unless the old ones were still intact, you are not gaining anything.

Also, IP spent may $$$ trying to figure out a way to determine the condition of the plates without removing them. X-ray, bore-scope, ultra-sound, thermal imaging...etc
No method was found that would give 100% reliable results.

I did ask Bill B. how may IP's that he knew of, has had the repair done?
Many dozen.

How many were bad?
He would not give me a number but did say that there have been a few.

[buzzstar]

Thank you, thank you. I have long advocated titanium chain plate replacements on other forums/groups, and have always been smacked down even for the suggestion.

[buzzstar]

Originally Posted by UNCIVILIZED

[COLOR=black]
Also, if it’s not prying too much, it’d be good to know where you’re having the Ti ones made, & what their cost is. Including a cost comparison for new stainless ones (polished or otherwise).With specifics on what particular metals are being used, or were quoted for.

If any knows for sure, is passivating -by polishing or other means- just as important for Ti as it is for 316? So if it is done by any means, please include the cost, separately if possible, but in any event in the total if you (A64) choose to provide it. Thanks.

[a64pilot]

You know I think if I remember correctly the eight chainplates from Allied Titanium was about $3K give or take, and in SS from Garhauer it was about $2K give or take.
Total labor and all materials except chainplates is $9K. The Ti wasn't much more, now they told me they could polish the exposed pieces inexpensively, but I wanted then bead blasted. I wanted them to look different from SS chainplates.

I do not believe there is any prep required for Ti, no passivating or heat treat etc. just water jet cut and weld together. I assume the holes were machined as a water jet can't be that accurate and won't cut a smooth hole.
In truth I have not seen them, I had them shipped straight to Mack Sails for them to inspect and make sure they were correct.
What we did was Mack Sails was replacing the chainplates in an IP 38 so they asked the owner if it was OK to ship an old one to have duplicated 8 times, I had it shipped to Allied Titanium and they gave me a quote.
I hope this starts something as in more IPs will have them replaced with Ti.

[CaptRory]

OK, As an IP owner that has been through this, I am going to weight in. First "encapsulated" means? The three IP chainplates are made of 304 stainless, all welded to a horizontal cross member and glassed into the hull. Picture glass strands coming up from 3 feet of hull, around the over and around the cross members at each tang and back down into the hull. It is a very robust installation. The problem was, prior to '97 models, there was no way for water that made it through the bedding to escape, hence setting up anaerobic oxidation. The fix is to take the furniture out, exposing the hull and grinding out the glass, releasing the old assembly and replacing it with a new 316 stainless assembly. This is more resistance to corrosion but also more brittle so they are constructed of a larger dimension. Post '97 models and those that are properly replaced have drain holes that allow any water out of the pocket, so if you fail to maintain your bedding, your cheerios will get wet and you will know you have a problem. Mine lasted 23 years and I expect the new ones to last forever.

[CaptRory]

Some more pics. I should add...an old boat that has been well maintained, that is regular rebidding will not have a problem.

[Frankly]

A hundred years from now I see some old dude standing there holding a titanium tang in his hand. "Great chain plates but the yacht must have been a POS."

[Frankly]

Capt Rory,

Picture looks like the port lower. What was the condition of the rest. I have long believed that the weld temperature/ talent is one of the variables. That picture shows the failure right above the angle weld. Weld decay in SS is well understood and is one of the reason for the switch to 316L.

Know you are happy to have that issue behind you.

[Stumble]

Originally Posted by buzzstar

If any knows for sure, is passivating -by polishing or other means- just as important for Ti as it is for 316? So if it is done by any means, please include the cost, separately if possible, but in any event in the total if you (A64) choose to provide it. Thanks.

Buzz,

I am not an engineer but I was the corporate attorney for a Ti fabricator and sold titanium a number of years ago to the marine world.

Titanium does not need to be polished, passivated, or prepared in any way prior to use. It can be, but it is a purely aesthetic choice and I never recommended it. It is (was) an expensive option that adds nothing mechanically or from a corrosion standpoint to the part.

Technically you could pull millstock titanium and put it directly into service, but it would look like crap, so I recommended a bead blasted or sandblasted finish to give it a uniform appearance. Again it isn't necessary but it looks a lot better for not much price difference. Like aluminium Ti can be galvanized, and it can be done to add color at the same time, but again is a purely cosmetic issue.