2002 Mk II Hatch

Robert Mann · February 03, 2019, 04:01:07 PM

I have been a victim of a small intermittent leak from the front left side of the main salon hatch. This a Lewmar 20.25" approx square hatch. On removing the inner trim I found the problem is more than a minor leak. The inner trim has enough of a channel around it to hold water and cause some rot in the core as it creates a pretty reasonable seal against the ceiling. The good news is the hatch is bedded in Butyl tape so it will be easy to remove and re-bed. Fixing the core, not so simple, so any tips on this would be appreciated.

This leak has been there for a long time, and appears to be from the hatch bedding and only shows up after the channel gets sufficient water in the channel to leak over the inner lip. The lip into the hatch recess in about 1.25" deep so seals up to the aluminum frame.

If you have a Mk II, I would remove the inner trim, by removing the screen clips (flip the little caps off with a pocket knife) and check that you do not have a hidden leak.

As Ron says, just a thought!

Ross Fisher · February 04, 2019, 03:26:29 AM

Pictures would help.

Jim Hardesty · February 04, 2019, 04:47:40 AM

QuoteIf you have a Mk II, I would remove the inner trim, by removing the screen clips (flip the little caps off with a pocket knife) and check that you do not have a hidden leak.

Never had a problem with that hatch leaking but, I'll add that to my spring to-do list.
As for your repair. Open it up and let it dry out and see just what problem you have.

Jim

Dale Stone · February 04, 2019, 01:13:33 PM

Thanks Robert, I'll add this to my list. I just finished a reply and noticed I got logged out.
Other prone areas for core moisture are:
> Chain plates
> Piano hinge attachment, cockpit seat to deck.
> seahood, envelope cover of the slide hatch

I redid the chain plates, completely redid them as I am very unimpressed with the original install. Also the deck aft the port winch due to the tiny loose wood screws holding the piano hinge on. I did a long explanation of that hinge repair and lost it because I was logged out without knowing. I can detail the repair and chain plate redo if you are interested.

The main message though is wet cores do not dry out. You have to cut them out and replace.

Good luck!

Robert Mann · February 04, 2019, 06:32:02 PM

Thanks Dale, I think my biggest issue is going to be exposing the core to be removed. I want to do it from underneath to keep the deck intact and not wrecking the color and non-skid match. I am not sure yet how to match the ceiling finish and color, once I have got the rot out. I'm now a little paranoid as I didn't see this leak for a long while and the core is wet and rotten, so I am now deciding if I want to start a massive re-bedding project, after completing the hatch project.

Noah · February 04, 2019, 07:20:36 PM

I would make the core repair(s) from working up on deck. Much easier than working inside overhead. You can get the non skid pattern and gelcoat color to match from either Catalina or other vendors. Pretty common pattern to stamp after repair. Example:

https://youtu.be/aoOtHe4g9m0
Good luck.

Dale Stone · February 05, 2019, 05:58:42 AM

Hi Robert,
I understand your dilemma. Do you know the extent of the wet core? A moisture meter may help but reading them can be tricky.
Repairing from the top side and bottom side has their pros and cons. If the wet core is close and contained to hatch openning, then digging it from the side may be an option.

Noah · February 05, 2019, 09:19:08 AM

Caveat: I am not an expert in wet deck core removal, but from what I've read/watched; a mosture meter will only get you "so far" wth regards to accuracy/location and the only true way to find the extent of the damage is to drill some exploratory holes.

Robert Mann · February 05, 2019, 11:09:06 AM

I think digging it out is not really an option, as it will be difficult to make sure all the failed core is out. I think that from doing some probing the worst spot is about 8+" deep, so from either the topsides or from underneath I'm looking at removing about a 10" "L" shaped piece around the hatch frame corner.

I have Butyl tape to re-bed the hatch but I am concerned about sealing up the screws that hold the hatch to the deck. These are stainless self tappers not through bolts so I need to figure out how to seal the rotating screw as opposed to a stationary bolt such as is used through a cleat etc.

Noah · February 05, 2019, 11:58:54 AM

For deck penetrations I would use the drill holes oversize and fill with epoxy then redrill pilots into the epoxy, so that whatever fasteners used (bolts or self tappers) don't touch the core material. Sikaflex or 3M 4000/4200 should work on sealing self tappers. Butyl for bolts.

hwd · February 06, 2019, 06:27:53 AM

I'd like to check to see if my boat has a similar problem. Please explain how I remove the inside plastic hatch liner
thanks

Robert Mann · February 06, 2019, 08:53:55 AM

The little catches that hold the bug screen in place, when it's fitted, are held on by through screws. These screws also hold the trim ring in place. There are 8 of these catches. Take a pocket knife or similar tool and gently pry of the domed cover over the catch and the screw is then exposed. This works on the Lewmar hatch on the MkII boats.

Roc · February 07, 2019, 04:00:42 AM

My plastic trim seems to be also held in place by the caulk that most likely squeezed out when CY installed the hatches. Taking the screws out still leaves the trim securely in place. I've wanted to remove them to give them a coat of white paint (they yellowed), but never did it because I'm afraid they would crack. I suspect they probably are brittle due to age. So, I've left them alone. No leaks at the moment.

hwd · February 07, 2019, 06:55:32 AM

Robert,
Thanks for the information on how to remove the interior hatch trim. Sorry to hear about the water problem with your deck core. I'd be very interested to hear how you decide to fix it.
Harry

Robert Mann · February 07, 2019, 06:56:19 PM

Roc, mine was sealed with Butyl tape from the factory, and it's still pliable nearly 17 years on. Might be yours is bedded the same way? The ring was a fairly snug fit in the hatch opening. I used a flat scraper to gently get mine down.

Harry, after talking with Catalina i am going to try and dig the core out and pump in a filler of some kind after I dry it out. CY suggests Arjay 5121, but I can't find that in affordable quantity, <5 galls, I'm thinking of resin with a thickening agent and micro balloons and pumping it in with caulking tubes, but I'm not self convinced yet. I need to get the core out first and really find the extent of the damage.