Chain plate leak

[djones]

Hi All,
I'm starting to see some water leakage at two of my shroud attachment plates inside the boat. The plates look like they are attached to the deck with four bolts, and the plate is grabbed underneath by a ball and socket arrangement.

Has anyone dissassembled and rebedded one of these yet? I don't see how the ball can disconnect from the bottom of the chainplate. Maybe the whole assembly has to come up through the deck after loosening the cylindrical turbuckle mounted inside the boat near the lower hull attachment point?

Thanks for the help!
Don Jones, #13 "Onatop"
Oak Island/Southport, NC

[william vanwagoner]

I had this problem about two years ago, and made the following set of notes. The chain plate that comes through in the shower compartment was leaking. I asked for help on the C350 email list but received no replies, which I took as good news as leaky chain plates must not be a big problem on the C350. I called Warren Pandy at Catalina Yachts and asked him about it prior to tackling the job. Upon examination, my biggest concern was how to restrain the tie rod from rotating when tightening the large nuts at the base. Warren indicated that when they assembled the boats, they did not seem to have trouble keeping the tie rod from twisting. Furthermore, Warren pointed out that there is no wooden core in the deck where hardware such as this is located which is great news and a testament to the detail taken in the design of our boats as there is no worry about a rotting deck core. With these words of wisdom, I did the following (keep in mind the chain plate that was leaking in my case was the one on the port side that holds the main shrouds.):

1. I attached the spinnaker halyard to the forward shroud chain plate and tightened it a bit to help support the port side of the mast.

2. I loosened the port side upper and lower main stays until they could be removed from the chain plate counting the number of turns as I went.

3. I loosened the bolts holding the chain plate on the deck

4. I removed the plastic access plate on the shower stall wall and removed two large nuts, a lock washer, and a flat washer, and an aluminum block milled to a custom shape to rest on the bracket so that the washers and nuts are perpendicular to the tie rod.
5. Very Important! - you must hang on to the aluminum block, it is not stuck to the bracket, and in my case fell down into the abyss between the shower stall wall and the hull. I had to use a coat hanger to coax the block back up to where I could get it out of the access hole. This added at least a half hour to the job, and had I not been able to retrieve it, would have delayed things for days or weeks while waiting for a new custom aluminum block from Catalina.

6. Clean all of the old adhesive from the chain plate tie rod assembly and the bolts. I should note that the chain plate assembly is an interesting unit. The tie rod is threaded at the bottom end which goes through the aluminum block, a flat washer, a lock washer, and finally two nuts. All of this holds the bottom of the tie rod to a metal bracket glassed to the side of the hull. There is a ball joint at the top end of the tie rod, which sits in a cup shaped piece of stainless steel visible from below deck (the deck was at least two inches thick at this point). This cup is welded to the bottom of the part of the chain plate you can see above deck. This forever captures the ball joint linking the tie rod to the chain plate.

7. I used 3M 4200 adhesive to form a strong flexible bond but one that could be removed if the job needs to be repeated in the future (unlike 5200). I placed tape around the outline of the chain plate both above and below decks, I should mention there is a thin plate that partially covers the underside at the headliner which is held in place by the nuts holding the chain plate bolts. The tape keeps the adhesive from spreading out over the deck on the outside and the headliner on the inside.

8. I then glopped the adhesive on the deck, on the sides of the hole where the ball joint cup goes, and below on the headliner, and re-inserted the chain plate assembly through the hole remembering to slide the headliner plate over the tie rod end before the tie rod goes into the hole at the back of the shower stall.

9. Then I inserted the four bolts holding the chain plate to the deck. I tightened the hex nut, acorn nut, and lock washer mix on each but only a little more than finger tight.

10. Then inside the hole behind the shower stall, I put on the aluminum block, the flat washer, the lock washer, and the two large nuts, being careful not to drop anything this time. (I cheated and stuffed a few micro fiber towels in cavity below the hole to catch anything that I might drop this time). Then I made sure the aluminum block was situated correctly before snugging the two large nuts hand tight.

11. I left everything hand tight and left the boat for about twelve hours letting the adhesive set up a bit. Upon returning to the boat, I tightened the four chain plate bolts. Then I managed to get a wrench inside the hole behind the shower stall and tightened the top nut while holding the tie rod by hand to resist twisting. Then did the same with the bottom nut which I believe is there to lock the upper nut in place. (I checked the other nuts at the base of the other tie rods and found one that was loose, so this is a good thing to check periodically).

12. I re-attached the shrouds and tightened them the same number of turns it took to loosen them. Checking with my rig tensioning gauge, things were not quite in balance, so I wound up removing all of the cotter pins on all of the shrouds and proceeded to tune the rig to get uniform tension while periodically sighting up the mast to make sure it stayed straight.

13. I took the boat out sailing and did a bit of fine tuning replacing all of the cotter pins upon return to the dock. All of this took place the weekend prior to Easter (2009), and so far no leaks (March 2011). In hindsight, I probably should have loosened all of the shrouds since this job necessitated re-tuning the rig anyway.

[djones]

Thank you for this detailed information Bill!

One last question... On the lower tie rods that go from the underside of the deck down to the hull attachment point, is yours a one piece solid rod all the way? I have what appears to be a cylindrical turnbuckle-type device on each tie rod. This is on the section inside the boat. They are positioned below the inner hull liner, so can't easily be seen, except for the one in the head beside the holding tank. Do you have these adjustment cylinders, and if so, did you have to mess with them at all?

Thanks,
Don Jones

[william vanwagoner]

As I recall there are both types. The one I worked on was the main shroud chain plate which has the solid rod. I recall seeing the adjustable. i.e. turnbuckle, on the forward shroud which I have not taken apart. I assume the ball and socket is similar but the turnbuckle might make it easier. I would mark the location of the turnbuckle relative to both upper and lower tie rods before loosening so that you can get the same tension between deck and hull connection point when putting it back together. It may also be possible to leave the turnbuckles in place and removing the hull mounting point but you will need to look at it to ne sure. In any case, be very careful not to let parts fall down into the hull. However you do it, I expect the details on how the chain plate attaches to the deck is the same as the long tie rod setup. You have me curious about this now and will take a look at the turnbuckle chain plate setup on my boat this weekend. If you tackle this project, I would suggest writing up a set of notes on what you learn about the turnbuckle type chainplate and post it here for future reference

[william vanwagoner]

I took a look at my boat this weekend, and there are turnbuckles on the forward shroud chain plates (port and starboard) with solid tie rods on the main and aft chain plates. It looks like the turnbuckles will need to be undone (so marking the pre-loosening point is probably very important) as the turnbuckles themselves will not fiit through the various holes in cabinet pieces etc. However, it looks like the turnbuckle only serves to link the upper tie rod section to lower tie rod section, so the remainder of the job is probably the same as the solid tie rods. I would be very careful to make sure the bottom tie rod and assoicated bolts and washers etc. at the end do not fall into the hull as you remove the turnbuckle.

Good luck!

[djones]

Thanks Bill. I looked closer at our boat as well. It is rigged the same way as yours, with the internal turnbuckles only on the forward shrouds. The chainplate that is leaking has the turnbuckle, so will probably attack that very soon. I may just rebed all of them while the rig is loose.

Thanks again.
Don

[C350ia]

Did this repair on mine a while back. Just a couple of things I might add. Main and forward shrouds were leaking. Make sure you turn the main chain plate the right direction when you reinstall. Sun was going down on me and I got in a hurry, wanting the caulk to set overnight. When I got up the next morning I discovered I had installed it backwards. Had to take it up, clean off the caulk and reinstall.

I couldn't get the socket to go on the forward shroud nut so I removed the bolts on deck one at a time, cleaned the caulk out as best I could then squirted caulk in the hole and reinstalled the bolts. So far I haven't had any leaks from either one.

[william vanwagoner]

See my previous post below with pointers on this job. As I recall the entire assembly, tie rod and all, is pulled up through the deck. Not a real hard job but don't let any parts fall down between the hull and liner.