Hull/deck Leaks

[thwilson]

My 1986 Catalina 30 has some leaks where the hull connects to the deck. I've tightened the bolts in those areas which helps, but still have a leaking issue.
Is there some sort of sealant I could use to apply in those areas?
Thanks,
Tom Wilson
Bainbridge Island, WA

 

[FastOlson]

Are you describing leaks from rain or from sea water hitting the hull when you are heeled over?
Suggest you contact Catalina Yachts and find out exactly how you deck is joined to the hull molding.

 

[ggrizzard]

Your leaks may come from items attached to the deck, such as stanchions, tracks,
anchor windless or bow roller. They may also come from the bow pulpit,
forestay chain plate or the chain locker.
If so, I recommend butyl tape as a re-bedding sealant. It's available here on the SBO store.
There are several 'flavors' of the stuff out there, but the one from this site is the best.
It is also the sealant used on my 43 yr old, 30 ft. sloop by the old Hunter Marine to seal the
hull/deck joint, which has never leaked.

 

[stickinthemud57]

3M Marine Sealant is the go-to product for this sort of thing.

In my experience, sealing leaks is a trial-and-error process. Often you seal what you think are the problem areas only to find you still have a leak.

Here is a link to a thread in which Crazy Dave Condon shows a way to pressurize the cabin, enabling you to find the leak points using soapy water, like you do for a tire leak.

It occurs to me that reversing the blower might aid in the sealing process by helping pull the sealant into the leaky area. Just a thought.

 

[jssailem]

With all the rain you have ben having this winter. It is no wonder water has found the areas weakened by age and taken advantage.

The usual suspects are the many fittings we put through the deck, or the ports we use to look out of our boats.

Carefully examine the boat leaks to identify their likely source. Then plug the leak from the out side.

The least likely source would be the hull to deck joint. It is also the most difficult to fix. Fix all of the deck hardware and openings first. They are tedious but easy.

 

[stickinthemud57]

Fix all of the deck hardware and openings first. They are tedious but easy.

Like the guy who lost his wallet up the block searches under the streetlight "Because the light is better"

I agree with jssailem's approach, and would agree that they are the most likely and most easily addressed points of failure.

 

[Joe]

This might seem a radical solution, but you could apply the sealant (I think 5200 is the accepted hull/deck joint adhesive) from the outside. This means, of course, removing the rub rail. A daunting task. Years ago I was reading "20 small boats you can sail around the world" and the guy that circumnavigated his Cat 27 did that as part of his boat prep. I guess you could try it without removing the rub rail, too, but a complete redo seems to have a greater possibility of solving the problem.

 

[Ward H]

While I agree there are many places on a deck which need to be properly sealed to prevent leaks, if there is damage to the rub rail and holder, water can seep under the holder and enter through loose screws and open holes in the hull deck joint.

This is a timely thread as I removed damaged sections of the aluminum rub rail holder yesterday on my C30. This was damage from the PO.
The deck to hull joint is the Shoe Box type joint. The deck over laps the hull. It appears to have an adhesive/sealant between the joint.
Mechanically the joint is held together with the screws that mount the rub rail holder. The holes for these screws of completely thru the joint. In the area of the two louvered salon cabinets and forward of the bulkhead the rub rail holder is thru bolted.

Normally I have almost no water in my bilge but since I removed the old brittle rub rail back in January I've had several inches of water in the bilge monthly. Yesterday I found several loose screws in the areas of the damage rub rail holder and two of the thru bolts had slight rust on the threads. There were many old holes under the holder that were open. Maybe temporary screws were used to hold the joint tight while the adhesive/sealant set?
This all indicates to me that by removing the vinyl rub rail rain was able to get thru the loose screws failed sealant and run down the inside of the hull to the bilge.

Today I'll be trying to squeeze some 3M 5200 up into edge of the joint before putting on the new rub rail holder. I'll be using either 3M4200 or Sikiflex 291 in each screw hole before I put the new screws in.

 

[Project_Mayhem]

As @jsailem mentioned, it's more likely to be a deck fitting in another area letting water in and then it finally seeps into the cabin around the hulll/deck joint. Hull/Deck joints are one of the only places that 5200 should be used. Not all builders used it there so it can't hurt do do some research to find out what Catalina used. Silicone is a no go with the rare exception of specific types for surface mount plexi window replacement. As for your deck fittings, it's recommended to remove them, clean out the old sealant and rebed it with Bed-It butyl tape. In some cases it's more appropriate to use 4200 but that's a discussion for another time. I'd be happy to share the tips I learned during my rebedding project.

 

[Crazy Dave Condon]

Use to be a Catalina dealer too and Frank Butler use to ask me what to do on small boats.
Catalina used both 5200 on the hull to deck joint but at times butyl tape too. Contact Skip at the Catalina plant in largo, fl. California plant closed years ago.
First, post photos if there is any damage to pthe rub rail to eliminate any damage. Secondly, look for deckside and rub rail leaks which is an old trick of marine yards use but doesn’t tell the public

Topside leaks are hard to find. First tape over any forward hatches. Then tape plastic over the companionway putting a small slit in the plastic. Place the nozzle of leaf blower into the slit and tape around it too.
Have another person standby with a bucket of soapy water and brush. Turn on blower and start brushing everything on top of the deck to include the rub rail. Where you see air bubbling out is a potential leak.
Hope this helps

 

[DArcy]

I am not familiar with the Catalina 30 hull to deck joint. If it was sealed with 5200 as Dave says it should still be sound. The sealant on my boat dried up and became brittle. This is now a known problem with the Islander Freeport 36. Fortunately it is not a technically challenging repair, just very labour intensive. If you are interested on how I made the repair have a look at this link

Resealing the Hull to Deck Joint

I've had this boat for a year now. I knew there were some rain leaks but I didn't know where. The previous owner thought the large saloon windows leaked and he had this crack seal stuff he would apply now and then. I've never seen that stuff work so I started removing and rebedding the windows...

forums.sailboatowners.com

My boat was very definitely leaking at the hull to deck joint. I was aboard during a particularly heavy rain storm and saw the water dripping down along the hull at the back of a locker. The repair resolved the leaks. During the repair I did find some damage (and a previous questionable repair) that made the issue worse, but the sealant was very brittle so it didn't take much damage to precipitate a leak.

 

[thwilson]

Are you describing leaks from rain or from sea water hitting the hull when you are heeled over?
Suggest you contact Catalina Yachts and find out exactly how you deck is joined to the hull molding.

My leak issue is due to Seattle rain.

 

[jssailem]

Seattle rain.

There are a couple of answers.

• Buy a tarp and cover the area leaking
• tape green garbage bags over the leak source
• find one of those fancy lake front boat garages. Tall roof needed
• sail south for the winter, Baha ha ha, avoiding the persistent drizzle/frizzle/rain/ice/snow exposure.
• hope the thick layer of winter moss will soak up the surface rain.

Fielders choice.
(see how I slipped in a Mariners seasonal reference in there).

 

[JamesG161]

I used a 5 gallon bucket of water with Red Easter Egg dye in it. No staining type.

Put some white paper towels in suspected areas first.

Pour Dyed Water over the deck area.

Found my leak fast.

Jim...

 

[Crazy Dave Condon]

@jssailem

got a good laugh