SailNet Community banner

21 - 35 of 35 Posts

·
Registered
Joined
·
994 Posts
It won't dry out. Take it from the sailors who have spent countless hours ripping out their core. When you make the first cut water will pour out.

Check my blog for pics and comments on this exact subject. Check the links at the bottom of the blog, they contain info I have gathered for this same exact subject. Escpecially the "rattle and hum" blog(goto first post).

Mango Madness J30 #185 rebuild
 

·
Thanks Courtney.
Joined
·
3,954 Posts
If it is bigger than one square foot... it generally needs to come out. Also, it depends on the area and what kind of loads it is under. The side deck may have greater loads on it if it is near the chain plates or has to support the chain plates or the genoa track...
After much looking for a mystery leak, I found it. One of the screws that went up thru the coach roof and secured the teak grab rail on the roof had been leaking and running down the headliner. After removing the headliner I discovered the leak and found a section of delamination with wet core that is 2ft. fore and aft by 1 ft. wide. I sealed around the hole externally and re-secured the grabrail adding a BIG SS washer inside. When I tightened the screw/washer it literally squeezed water out thru the glass on the inside. (Not around the hole, THRU the glass.) It is clear that the water is not sealed inside, ala glass jar, as the glass seems to be porus. Any thoughts?
 

·
Super Moderator
Joined
·
6,803 Posts
Can you show us a picture of the porous glass around this screw? I would more likely guess that it squeezed out from behind the fender washer and not through the fiberglass? Old Tartan deck skins are usually quite thick.

This is a fairly standard piece of balsa cored deck laminate. The drill is a 5/16" bit so as you can see these skins are certainly thick enough to not be porous. I would not believe your Tartan is constructed much differently.
 

·
Thanks Courtney.
Joined
·
3,954 Posts
No, it was difinatly coming thru the glass. (inside) I was quite surprised to see it. I backed off the screw a bit and re-tighted. Same result of water coming thru small pores in the interior glass. Water drops appeared on the inside surface of the coach roof in 10 or so areas around the screw (covering maybe 6" x 6")when the core was compressed by tightening the screw.
 

·
Registered
Joined
·
207 Posts
If you are actually able to squeeze water through the glass skin, I would be more concerned about the integrity of the lamination. I am in the process of repairing several large areas of wet core and delaminated core on a 1972 Pearson 30. Some of the araeas I am working on the core was fine, not delaminated but just soaking wet, other areas must have been wet for a very long time and the balsa core was like mush , like maybe rotted oatmeal and in these areas the skin laminations themselves had succombed to the constant soaking and had begun to become pourous and soft, the entire structural integrity of the laminations had failed. SO if you can squeeze water through the skin lamination I would say that you not only have to replace the core but the skin lamination itself is justy as big an issue. SO drying out the core(if even possible) still leaves you with suspect laminates. My recomendation?..Get out the grinder and cut off the offending area of skin, scrape (or pour out) the rotted, mushy core and replace the core properly and relaminate a new skin. I have just finnished the aft port side of the cockpit seat by going from underneath, it is hard working upside down from under the seat but the outer skin is perserved. I will do the ame on the starboard side. These areas let water in via the travelor mounting screws. The other area is the cockpit sole,aft of the center of it where the fuel fill is located, about the aft two feet of the cockpit sole and around the rudder post. This I will do from the top side as, for one thing, there is hardly room enough below the sole to do this kind of work. I removed the fuel tank but it still is very tight squeeze. Also, the outter skin(topside) has flexed so much due to the rooted core that the laminations are beginning to fail so cutting that out and relaminating a new outer skin is the only sensible thing to do IMHO. Also, It will go alot quicker working from the top, as well as much easier. The whole deck will get re-finnished (painted) when all these repairs are complete.
 

·
Thanks Courtney.
Joined
·
3,954 Posts
That is kinda what I was thinking. The exterior surface is intact and has no problem at all. The issues are only visible fromt the inside. Core does seem spongy (mush) with the water coming thru interior laminate. Area is 2' x 1' of te interior coach roof. Very easy access now that the headliner is out.

Can someone point me to a discussion "how to" do the core replacement, materials to use, directions, etc...? I've not done glass work before, but happy to start.
 

·
Super Moderator
Joined
·
6,803 Posts
No, it was difinatly coming thru the glass. (inside) I was quite surprised to see it. I backed off the screw a bit and re-tighted. Same result of water coming thru small pores in the interior glass. Water drops appeared on the inside surface of the coach roof in 10 or so areas around the screw (covering maybe 6" x 6")when the core was compressed by tightening the screw.
'

While I've never heard of it or seen it you may have osmotic blistering going on between your deck skins. Now that's WET!!!

I would drill a test core, in a known dry area, to get a look a the thickness of the skin laminate. If it is anywhere near the thickness of the previous photo then my guess is that your deck is so wet that it's blistering from being water soaked. Perhaps the added heat from the sun on the deck has accelerated the process??
 

·
Super Moderator
Joined
·
6,803 Posts
That is kinda what I was thinking. The exterior surface is intact and has no problem at all. The issues are only visible fromt the inside. Core does seem spongy (mush) with the water coming thru interior laminate. Area is 2' x 1' of te interior coach roof. Very easy access now that the headliner is out.

Can someone point me to a discussion "how to" do the core replacement, materials to use, directions, etc...? I've not done glass work before, but happy to start.
Before you rush into things buy yourself a moisture meter so you know exactly what and where you are dealing with. You can buy one for under $200.00 delivered from Electrophysics in Canada. This expense will, in the long run, save you money.

Read this for more info.

Understanding The Moisture Meter (LINK)
 

·
Registered
Joined
·
108 Posts
Core drying takes a long long time. My old boat had wet core problems, it was on the hard for over a year. I did some of the work and a contractor did some of the work. It cost a fortune and took lots of time and hard work. Between a very knowlegdable surveyor, myself and the contractor, we came up with a solution that should let the boat be sailed coastal only for a very long time; no blue water passages.
 

·
Telstar 28
Joined
·
993 Posts
There have been several threads on re-coring a deck over the last two years. Be aware that doing so from the bottom up is significantly more prone to failure and voids than doing so from the top down, since gravity is against you. The only way to reduce the chances of a bottom up repair is to vacuum bag the repair area...

The actual core material you use will probably be up to what the current deck layup consists of. If you have a balsa cored deck, you should generally replace it with balsa... if it is foam cored...replace it with foam... etc.. The same goes for the glass laminating schedule... First place to look is West Systems Epoxy site... they've got a great resource online for doing such repairs.

Personally, I've never heard or seen fiberglass being so porous that water was able to weep through it at a rate fast enough to observe—even under pressure. I'd take a chunk of the laminate out using a hole saw and see if the GRP there is resin-starved, which is about the only way you're going to get big enough holes for water to weep through at that kind of rate IMHO.

That is kinda what I was thinking. The exterior surface is intact and has no problem at all. The issues are only visible fromt the inside. Core does seem spongy (mush) with the water coming thru interior laminate. Area is 2' x 1' of te interior coach roof. Very easy access now that the headliner is out.

Can someone point me to a discussion "how to" do the core replacement, materials to use, directions, etc...? I've not done glass work before, but happy to start.
 

·
Registered
Joined
·
198 Posts
Discussion Starter · #31 ·
So after spending the winter some 800 miles from my boat, we are finally back together. I driled some core samples in the area in question. Moisture, yes. Running water, not even close. The fiberglass came out as dry powder, the wood came out as normal, but wet, drill shavings. Glass and core are firmly attached, and it is virtually impossible to pick apart the core. I am using heat lamps on the surrounding deck, and things appear to be drying out nicely. I plan to drill more core samples and repeat as needed.

It would naturally follow that there is a time period between origin of a leak and complete destruction. The problem would be that this sort of thing isn't noticed until the deck is squishy, whereupon it's too late. As for me, it'll be a complete rebedding, regular checks with the moisture meter, and early action of future problems. She's an old boat, she doesn't have to be pretty.

Thanks to all for your input. Fair winds!
 

·
Irrationally Exuberant
Joined
·
1,421 Posts
Hey, thanks for coming back with the followup report! Too many dangling stories out here. :)
 

·
Registered
Joined
·
4 Posts
Sorry to hear about the deck problem. I have a similar problem on a 1973 Tartan 41. This is about 5th on my list of major repairs prioritized by safety at sea issues such as keeping the rig up. Pease let me know your plan of attack and what materials and information you have gathered. From what I have learned so far, the best way to proceed is to remove all the hardware, peal back the top layer of glass and remove and replace the core. I would like to do just the "soft spots" but I am afraid that the once I get into it the "spots" will expand to include most if not all the deck area. I also am thinking of experimenting with attacking the problem from underneath the deck..... ???
 

·
Registered
Joined
·
4 Posts
Hi, Just read your recent post and I am glad to hear the core was is decent shape. I do not think I will be as lucky. Soft spots feel pretty spongy and are next to such things like deck prisms, cleats and tank openings. I think it will be a project.
 

·
Tartan 27' owner
Joined
·
5,241 Posts
I went through a side deck re-core project last spring:
2013, May 2nd. Re-core work party. | Odalisque

Looking at some of the photos from my "project" I can see that we probably had leaks originating in the ports and a stanchion post where the bolt pulled through.

I've still got a bunch of work to do though to say it is finished...
 
21 - 35 of 35 Posts
Top