leaking hatch

[chergui]

My forehatch was leaking through the screw holes so I took it off to inspect and repair. The main hatch frame sits on the deck and screws are driven up into it from the bottom, through the hatch carlins and plywood deck and into main frame to fasten it to the deck. The frame was bedded, but not very well I suppose. Lots of dirt underneath and very little sealant to prevent water from getting underneath (it lifted off with ease). I guess it had just worn away over time and water was making it's way down. It wasn't leaking like a seive but I noticed it in the spring once and have kept the canvas cover for it on since, still.. was surpised it was as wet as it was.

The hatch frame is teak and it appears there is no rot. The carlins seem to be fir but I'm not too sure. A lot of rusty water came out when I took out one of the bronze screws. I was sure there was some rot but after poking and prodding, I couldn't find any evidence of it. How can you tell when wood is in an initial state of decay in a screw hole that you can't see but you know may have been wet for a while? Or if it's not obvious, do you assume it's ok and just let it dry and fix the problem. The deck was also a concern but it seems there was enough sealant in there to protect it.

Wondering what should I use to re-bed the hatch frame with. I read Bob's bedding post (http://www.woodenboat-ubb.com/cgi-bin/UBB/ultimatebb.cgi?ubb=get_topic&f=1&t=011799&p=). Is that Vulcum 116 polyurethane sealant appropriate or would a polysulfide be better? How often do you typically re-bed things anyway?

I'm planning on filling the screw holes with epoxy and redrilling them before reinstalling the screws as I'm not sure if this was done before.

[Adamant]

I'm no expert but I think I'd use polysulfide instead of polyurethane. I'd also epoxy dowels in the screw holes.

[Bob Cleek]

(I always wonder why people who try to answer a question start by saying, "I'm no expert, but..." I'm not going to tell you I'm no expert... But if you KNOW you aren't an expert, STFU! LOL) You need to remove the hatch coaming by taking out all the screws. Let the wood dry (i.e. no wet wood). If there is no soft wood, soak the wood well with CPES, paying particular attention to getting it into the screw holes as best you can. Bed the hatch coaming with BEDDING COMPOUND (Dolphinite is popular and good), not a poly-anything... PLEASE. (Remember how easily your hatch came off...) That should solve the problem for a good long time.

[ 09-30-2005, 02:21 PM: Message edited by: Bob Cleek ]

[Adamant]

Wow.I had no idea cpes was needed on teak. I thought teaks rot resistance was such that it didn't need plastic to survive.
As for what to use; myself I would call 3M product information center 1-888-364-3577 and ask for technical assistance. They may be able to help you determine which polysomething would best suit your needs even if you don't use their product. Modern compounds have been developed to suitspecific needs and I am not an expert but they are.
By what you described your teakdidn't fail, you're bedding compound failed. If superglop had been used to set the hatch instead of bedding compound you wouldent have had a leak.
I don't mean to humiliate Bob, he seems to be very knoledgable about some things. I have read many of his posts and did have quite a bit of respect for his opinions. Too bad you can't know it all.

[chergui]

Thank you both for your comments. Stewards "Boatbuilding Manual" says to use either polysulfide or polyeurethane. If you read 10 different things, they all suggest using something different. The CPES is for the deck and the fir carlin so I think it's a good idea. I've never used it before. I'm going to try the bedding compound because the poly-whatever didn't work all that great last time.

[Bob Cleek]

The CPES will stabilize any "soft wood" in the screw holes, which may or may not (likely not) have any decay issues. It is also the only worthwhile sealer for finishing teak with varnish. The bright finish will last many times longer.

There are a number of reasons not to use plastic goop on a wooden boat. Two of the most significant are 1) it is extremely tenacious and disassembly at any later date will likely damage the surrounding wood and 2) it often will not form a suitable bond with wood, particularly in a damp environment. Standard bedding compound (e.g. Dolphinite) is far easier to work with. (Cleans up with a kerosene or paint thinner soaked rag.) It is also much less expensive. It will remain flexible and will stick to the wood properly. Most importantly, it will allow disassembly easily if the need arises, as it usually does... if not when you own the boat, then when a later owner does. Also, when wood joints move, as they always do, the polysulfide compounds, if they are sticking, are stretched and often break their bond, resulting in more leaks. Traditional bedding compounds which remain "uncured" will move and "reseal" when the wood works.

Will plastic based compounds prevent leaks? Certainly, for a little while or even for a long while. Are they the "right" way to do it? NO! If it is worth doing, it is worth doing right.

[kc8pql]

One more little hint. No matter what you bed with, don't crank the screws down super tight. You'll squeeze out the compound, which sounds like what happened the first time. It can't work if it's not there. For things like hatches that don't take a lot of live load, I like Dolphinite. For things like stantion bases that do, I use polywhatever.

[pcford]

Da Cleeksta is back!....and he say:
(I always wonder why people who try to answer a question start by saying, "I'm no expert, but..." I'm not going to tell you I'm no expert... But if you KNOW you aren't an expert, STFU! LOL) I guess I never got a chance to understand what makes you an expert. Please share that with us.

[Adamant]

Thank you for not giving me another STFU! LOL.
If opinions didn't differ life wouldn't be very interesting.

[pcford]

Thank you for not giving me another STFU! LOL.
If opinions didn't differ life wouldn't be very interesting. Newbies don't bother me. Why should they? We all had to start somewhere. People that loudly proclaim themselves experts and give advice which is sometimes at best dubious does vex one.

[Peter Malcolm Jardine]

Take your arguments on expertise to the bilge. ;)

[Stiletto]

Now, that's an expert opinion! tongue.gif

[Jay Greer]

Aside from all the smoke and mirrors along with verbage and abbreviations. I have to agree that drying out the wood is the the first order of the day. Gawd, I hope that the plywood has not gone soft in the endgrain! Sealing the endgrain, once dry with CPES is a given. Teak is another thing. I never worry about sealing teak, unless it is to prevent oil based bedding compound from drying out. There was no mention as to how the corners of the hatch frame are joined. But, in many cases it is wise to add cedar stopwaters in way of the joint, especially if they are, God forbid mitered! I prefer varnish to seal teak that is to be bedded. In addition to the oil based bedding compound, a string of candle wicking soaked in linseed oil will make a tighter and more forgiving seal under the frame if it lands on the subdeck.

[Adamant]

I agree that most woods could benifit from CPES (especially plywood from plywood trees) but I prefer modern sealants. Their bad rap comes from improper application. Older methods of repair also work well but I prefer the systems developed after WW2. I use electeicity not oil lamps.

[Al Kahawl]

Ifa ya plan ta ewze da same holz I tink ya shud put sum sawdust er sumtin in da poxee.

[chergui]

Hi Jay. The plywood end grain was soft last weekend because it was wet. That's why I wasn't sure if rot was an issue or not. Checked it yesterday and it's dry and hard now after breathing for a week.

I think the joint is called a half lap. One of the laps has lifted up though because a snap for the canvas cover was screwed in and it has cracked one side of the frame. Looks like no pilot hole for the screw was made. I plan on fixing that before refastening the frame to the deck.

Interesting comment about the underside of the hatch frame being varnished. It is, and I had wondered why until now.

Jon