water damage on bulkhead

[John]

Attached are some photos of water damage on the bulkhead of my C36 MK II. Originally I had thought that the water was entering from the chainplate attached to the bulkhead. I reset all the chainplates, but the water damage continued. It's possible that I didn't do it right, but as you can see from the photo, some of the water stains are above where the chainplate passes through the deck. NOTE: The bulkhead is on the port side of the boat, alongside the mast and runs from right next to the mast all the way to the hull - thus passing under the (higher) cabin top and the (lower) deck, which is of course where the chainplate passes through. In other words, if it were only leaking from the chainplate, the water would have to run uphill on the bulkhead. I know water does funny things, but I don't think this is likely.
So I'm trying to figure out where the water is entering. The mast is keel stepped. Is it possible that it's entering around the mast? If so, would I have to pull the mast to fix this? Another possibility is the tutning blocks just behind and alongside the mast (see photo).
One final point: Originally I was going to pull and replace the bulkhead, but now I'm thinking of just routing out the dry rot, which is about a half inch deep and confined to the bottom and putting a piece of teak like a baseboard to cover it. Comments?

 

[Roger Long]

Are you sure it is rotted and not just discolored?

Rot is strange stuff. It moves with incredible speed, up to 3/8" per day, when conditions are right but mostly lies dormant. This is why is usually shows up where conditions are always changing. As the wood goes from wet to dry and back again, it moves through the moisture levels where the rot can flourish.

Dig out anything you can get easily with fingernails or dull tools. Then dry it getting it as hot as you can with a heat gun (be careful). Seal and cover. If you can stop more water getting in, the bulkhead will last as long as you have the boat. It's not like cancer where a few left over cells will flourish back into a problem. There will still be rot spores there but, if you can control the moisture conditions, they'll just stay dormant.

Be careful sealing that you don't create a situation where moisture is held in the wood promoting futher rot.

Just because it is black and wet doesn't mean it is rotting. If you can stop the water, you may be able to just leave it and consider the darkening part of graceful aging.

 

[Scott T-Bird]

I am not sure where you are showing the dry rot damage to be. Is the photo in the upper left turned sideways? What is shown in the bottom left?

I would bet that you are leaking water through the blocks. You could be getting some in from the mast and the chainplate as well.

I have the same problem on my port side chainplate ... over the years, there had been significant leakage thru the chainplate opening on the deck. It is the source of soft decks and dry rot in my bulkhead. I, too considered replacing the bulkhead. But I won't do it until I take the mast down again, which should be next winter. I have significant dry rot at the bottom corner of the plywood bulkead (which I have scoured out), just behind the teak trim. The main body of my bulkhead has some water stain, but no apparent structural damage. The bottom edge of my bulkhead is pretty much shot though, so I secured it to the fiberglass backing with some larger stainless steel bolts and oversized washers. It has solidified the construction but I consider it only a temporary fix. Obviously, my bulkheads are not tabbed into the fiberglass.

I have not removed the top plates to bed them properly and have tried to keep the leakage out by caulking the edges and making sure it is tight (at one point a couple of years ago I was horrified to notice that the plates were actually loose). I still get some leakage occasionally and I fear how much damage it continues to do. My decks need repair for sure already.

If you simply cover the dry rot with trim, and don't fix the leaking, you will only aggrevate the dry rot.

 

[John]

First, yes, the top left photo should be turned 90 degrees clockways. Second, yes I'm sure there is ro down at the bottom - that is unless the bottom is made from balsa wood. (I can push a knife about 1/2" into it.) The upper streaks are just water stains.

I'm gathering from what Scott said that I probably should pull the mast, remove the block it runs through & seal under it as well as under the blocks if I want to be sure that all leaks have been sealed. I'm thinking I can dig out the rot on the bottom of the bulkhead, maybe put some copper green in there after drying it, fit in a dutchman, and then put something over it for cosmetics. How does that sound?

 

[Scott T-Bird]

Why remove the mast?

Do you have a keel-stepped mast?

The blocks I would suspect first are the ones that are mounted to the deck. I would be surprised if the mast plate isn't bedded well, but even if it does need to be bedded, is it like a donut and can't you lift it up without removing the mast? If you do have leaking around the mast, I would have suspected the boot first, then the plate, but either way, I would only remove the mast for a last resort effort at finding all sources of the leaking.

I think the plywood bulkhead is most likely going to rot where the water puddles and leaves the wood saturated. The location where it occurred on our boat was at the bottom corner tucked away where the moisture could go un-noticed. Everything else is as solid as brand new, even if there is some water streaking.

I have a deck-stepped mast and intend to remove it next season anyway, that is why I have done a temporary fix for another season. I don't feel secure enough to disconnect the shrouds on the port side to re-bed the deck plate. If the mast was keel-stepped, I would think that a temporary support could be fashioned with halyards while you re-bed the deck plate. But it doesn't sound like that is the source of your leaking water anyway since you seem to indicate that it is coming from a location higher up in the coach roof.

BTW, my deck stepped mast is another source of leaking because I have all my wires coming down from the mast and running through the center of the foot. I always heard that this could be a problem, but it hadn't been a noticable problem for me until I removed my mast a few years ago and added some wiring which made it necessary to drill the hole out a little bigger. Now the water coming down the inside of my mast after a rain storm ends up on the captive fiberglass floor between the salloon and the fore cabin (where the head and a vanity is located) and it has made me realize how much it is a problem. The water also runs along the cabin liner and finds its way into the light fixture over the vanity!That is another job that I will be tackling next winter!

My boat is still a leaky boat and it is very frustrating trying to identify all the sources!

 

[Jim]

Are you sure the water is coming in the chainplates. It could be coming in from any penetration and making it way down the core and exiting the chainplate. I have the same problem starting on my boat C-36. I have seen many C-36 with this problem.

You have to understand that the quality of chainplates and deck penetrations are sub pair in my opinion. They have started addressing this issue on newer boats. For example Catalina added backing plates for deck amounted hardware.

Please post any thing you find that might be causing the problem I would re-caulk and end seal every deck penetration. The bulkhead problem you have is not acceptable. Call Catalina and report it.

 

[Stephen K]

John,
In addition to the other advice... if the head is on the forward side of this bulkhead, I would also check for a possible hatch, vent or portlight leak in that area. If so, water can run down the bulkhead and "seep" up along the bottom of the bulkhead. The damage will be seen on the "salon side" as the "head side" of the bulkhead is usually covered with a laminate surface.

 

[Jim]

Stephen is right. Also check that the shower caulk has not failed on the floor trim.

I think it is coming in the chainplate.... Nothing is going to stop it..

 

[Jim]

Ask the experts at the C 36 association

http://www.c36ia.com/?q=node/456

 

[John]

First: I have posted to the C36 Ass'n. but that list is nowhere near as active as this one.

I hadn't thought of a possible leak from the other side of the bulkhead, but that is possible. I fact, now that Stephen mentions it, I have noticed some dampness in the cabinet along side the hull in the head - just by that bulkhead. But again, the top of that area is the underside of the deck, and some of the water streaks are considerably higher than that.

As for the collar around the (keel-stepped) mast: On second thought, I think Scott is right that I should be able to lift that up without pulling the mast.

Jim (also a C36 MKII owner) mentions other areas where this model boat leaks. As I said on my original post, I now suspect around the mast and/or the turning blocks right by the mast. From Jim's experience, does he or any others know if this is a common problem to these boats?

Scott also mentions leaking through a (deck stepped) mast. I have another problem that I will have to address: This boat has in-mast roller furling. As those familiar with this system know, this means a ling slit up the mast into which the sail furls. Inherently, there is no way to prevent water - either rain or sea spray - from entering through this. I understand that later models have changed, but an absolutely idiotic part of this design is that there is nothing blocking this water from running all the way down the inside of the mast into the bilge.
My plan is to remove the furling mechanism and fit and caulk in place a piece of styrofoam inside the mast below this mechanism and then drill a small weep-hole just above it. This, however, has nothing to do with the bulkhead dampness since this water can only go directly to the bilge.

 

[Scott T-Bird]

I would suspect those dck mounted blocks for sure ...

Here is a picture of our interior. You can see the water stain alongside and below the chainplate on the port side. We have a solid teak vertical board just behind the stbd bulkhead and directly under the mast. I thought that it may act as a compression post, but when I tightened the rigging a few years ago, the bulkhead on the port side bowed just enough so that the door would not latch in the closed position.

You can't see the door in the photo because it is closed to the head (which is just behind the stbd bulkhead. It is a nice design that allows the folding door to close off the head, or close off the passageway from the salon to the gangway to the bow berth. The vanity is on the port side. When water leaks in through the hole in the mast shoe, it ends up in the vanity sink and on the fiberglass floor just behind the opening.

The port side bulkhead bowed because the bottom edge of the bulkhead lost its integrity and the screws that fasten it to the fiberglass behind it no longer held the wood solidly to the backing. I solved that problem by removing the trim and securing it with oversized bolts and washers. This picture shows the trim before it was removed and so you can't see the dry rot along the bottom edge. The worst of it was in the corner right at the end of the backrest. I can now tighten the rigging and the bulkhead is solidified so there is not compression in the coach roof causing a distortion to the bulkhead.

How do you like my speaker boxes? I didn't want to mount speakers in the bulkhead so I made the boxes and mounted them. I think they look a little big and clunky, though. I am not sure that I like them. The wood is ash so it is quite a bit lighter than the teak plywood and they seem to stand out too much. I used 3/4 inch wood so the boxes are also pretty heavy. If I were to lighten this rig for racing, the speakers would probably have to go!