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Water intrusion into balsa core
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localboy



Joined: 30 Sep 2006
Posts: 4169
City/Region: Lake Stevens via Honolulu
State or Province: WA
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: 'Au Kai (Ocean Traveler)
Photos: 'AU KAI
PostPosted: Sat Jun 16, 2018 3:19 pm    Post subject: Reply with quote

Drill, undercut and re-fill with epoxy now. It's only gonna get worse...
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Snider



Joined: 21 Jun 2013
Posts: 167
City/Region: Charleston
State or Province: SC
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Kestrel Dawn
Photos: Kestrel Dawn
PostPosted: Mon Jun 18, 2018 9:37 am    Post subject: Thinking Reply with quote

I'm still mulling this over. I'm thinking glassing in something to screw the starboard hold down strip into may be a little overkill. What I think would be the easiest fix would be to just drill out the holes in the deck, undercut them and fill it with epoxy and then just screw the starboard strip down into the new epoxy plug.
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22ft Cruiser
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thataway



Joined: 02 Nov 2003
Posts: 16943
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Mon Jun 18, 2018 12:35 pm    Post subject: Reply with quote

Either method will work. Be sure that the batten which you glass in or screw into plugs, is thick enough for the screws to get a good hold. I almost always use epoxy to glass in new items, since it has superior adhesion over polyester, in a secondary bond.

(I have been dealing with core water intrusion on the "new" 25, around the inspection ports and the "Steps" into the cockpit. Pulled the steps, and the 3/8" balsa core was complete dry in some places, in others it was saturated as deep as 3"--and this was water migration up! The sealants C Dory used in 2007 (and many earlier years just didn't do the job. I am going to use Loctite PL for Marine use--similar formula and specs to 3m 4000 (but cheaper). So much for just redoing the seams!

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Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
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Snider



Joined: 21 Jun 2013
Posts: 167
City/Region: Charleston
State or Province: SC
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Kestrel Dawn
Photos: Kestrel Dawn
PostPosted: Mon Jun 18, 2018 3:12 pm    Post subject: Thanks Reply with quote

Thanks Bob,

They are a labor of love. Hopefully we can do some of the organized cruises. That Cumberland river one looks fun.
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Snider



Joined: 21 Jun 2013
Posts: 167
City/Region: Charleston
State or Province: SC
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Kestrel Dawn
Photos: Kestrel Dawn
PostPosted: Thu Aug 30, 2018 8:12 pm    Post subject: Finally Reply with quote

So I finally tackled this job today. Hows your new 25 coming Bob, we're dreaming of one after hopefully getting many years out of our 22, lol.

The plan was just to do the port side first as I'd ran the tank almost empty but after getting going I just removed both tanks. There were/are 26 screws through the cockpit sole, 8 for the two battery hold downs, 14 for the forward and midship starboard strips that hold the tanks in place, and 4 at the aft end of each tank that holds the tie down strap.

On the starboard side one of the forward star-board strip screws had an elongated hole through the deck. Look like someone tried to remove the screw and put it back in at an angle so it would bite onto something and tighten. It just made a larger hole for water intrusion. I was able to stick a screw driver down in there and move it a good inch or so forward and aft and felt no balsa. So tomorrow I'm going to overdrill the hole and poke around in there to see what I can find, then eventually use either penetrating epoxy or thinned epoxy to fill it.

Now I have to find the best way to go back with these. Tentatively the plan is to overdrill all of the holes and fill with thickened epoxy, then use the wood screws (best screw choice?) and some sealant adhesive (3m 4200?) for the star-board strips that border the tank. For the metal strap that holds the aft tie down I'm thinking of eliminating those screws through the deck and glassing a block down to the cockpit, or just up on the transom to screw into. In "This Old Boat" by Casey he recommends laying some cloth over and under the block, other wise he says it will eventually pop off, any thoughts on this versus just sitting the block in thickened epoxy?

For the battery hold down I'll also glass some block down to screw those into. That will eliminate 12 screws.

I've considered glassing down the star-board strip that sit toward the centerline and are oriented for and aft so I could eliminate those screws but if I laid cloth over them it would create a little lip around the edge of the bottom of the tank and I don't want to do that. I've also considered just eliminating that forward partition and just strapping the tank down to the forward starboard strip as seen in that 90's C-Dory 22 on the for sale page. Lots of decisions to make in the morning, plus I need to take a hair dryer to the holes and make sure it's dry in there. I prob got a little water intrusion while I was cleaning the area.

I've also thought about putting a thin piece of rubber or neoprene under the tanks for cushion but I don't have a lot of clearance above the tank. I need to find some store where I can get something like that, any ideas?

I also decided to replace all of my fuel lines from the tanks to the filter, and I need to find a new decal for my fuel tank selector as the old one is faded but the lines were hooked up wrong anyway. Port drew from the starboard tank and vice versa. Sorry for the rambling, just thinking out loud.

Last thing, I was surprised to find 25gal tanks, the owners manual says 20 gal tanks.









One tank removed




Cleaning up the tanks



Just about ready for the install

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thataway



Joined: 02 Nov 2003
Posts: 16943
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Thu Aug 30, 2018 9:22 pm    Post subject: Reply with quote

Screw choice: I use pan head SS sheet metal screws--the wood screws are tapered and not much thread at the upper part of the shank. Occasionally I'll use flat head screws, but usually with footman loops, or other fasteners which have a beveled edge that the flat head sits flush to.

I would be sure all areas are filled with thickened epoxy--not just thin or penetrating epoxy. At this stage you should be able to sound out, with a plastic screwdriver handle (phenolic hammer is the classical surveyor's tool, but the screwdriver handle works as well.) Where there is the delimitation or wet core, you want to remove all of that. Not sure how much that will be--until you have sounded and drilled, etc.

I would glass over what ever were the cleats which held the tanks in place. That way there are no screws necessary. Starboard does not glue well. I have been trying some with "G Flee, and under cutting in a "Y" shape with a Fein type of saw. Seems to be working well. I also flame harden the Starboard with a propane torch.

You can glass in blocks--better than just epoxy under--but I have some blocks which are epoxied to the sides of the hull, and some which are glassed over. Both seem to be doing equally well at this point.

You can buy or make fiberglass "L" brackets You could use Starboard as a form--just put a little wax or teflon on the surface to be sure that the epoxy or polyester resin does not stick. Mold up what you need. If you use glass cloth and mat it will set up fairly quickly--then you can epoxy this to the floor, and have a permanent bracket for the facing boards.

I use heat guns (2 heats/fan speeds)--my wife draws the line at using her hair dryers. Just be sure you open it up enough. If there are large areas then get some core material, and put that in.

Anything you can glass in to screw to, is going to be better than the Balsa Core!

Thank you for asking about my projects--the boat is as ready as it is going to be in the summer of 18! Ready to roll to the Rivers. The side steps came out well, and no evidence of water intrusion. I am not so pleased with the Loctite PL Marine, which was touted to be the same as 3M 4000. I did some of the area where the seal around the removable floor section (fuel tank access) and around the steps turned yellow, and the adhesion to the fiberglass is not as good as I wanted. This area is covered by the Deckadence vinyl loop carpet, and with all of the rain we have had, when I pulled up the Deckadence carpet, There was some moisture trapped in the forward edge of the cockpit. I like the Deckadence; it looks better than the fiberglass cockpit floor. All of the dirt goes thru the vinyl loops, and it is all cleaned up in one short period of time. I pulled the Deckadence, and washed it from both sides, to get any dirt or debris out. After it and the deck was dry, the carpet was re-installed.
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Snider



Joined: 21 Jun 2013
Posts: 167
City/Region: Charleston
State or Province: SC
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Kestrel Dawn
Photos: Kestrel Dawn
PostPosted: Fri Aug 31, 2018 10:01 am    Post subject: Wet holes Reply with quote

If I get wet holes say in a 5 inch area around the mounting holes do I just drill say ľ holes throughout the area and fill with epoxy? Then paint it with something? I just drilled the mounting holes with a Ĺ bit and 5 of the 7 were wet. If you cut a square out of the top skin to replace a piece of core I guess you just glass it back down and fair it with gel coat or paint it? Thanks for the help.

Iím hesitant to explore the area forward of the tank. I hate to not be able to match the rest holes with the cockpit and they be visable. Prob needs to be done though.
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Snider



Joined: 21 Jun 2013
Posts: 167
City/Region: Charleston
State or Province: SC
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Kestrel Dawn
Photos: Kestrel Dawn
PostPosted: Fri Aug 31, 2018 10:03 am    Post subject: Re: Wet holes Reply with quote

If I get wet holes say in a 5 inch area around the mounting holes do I just drill say ľ holes throughout the area and fill with epoxy? Then paint it with something? I just drilled the mounting holes with a Ĺ bit and 5 of the 7 were wet. If you cut a square out of the top skin to replace a piece of core I guess you just glass it back down and fair it with gel coat or paint it? Thanks for the help.

Iím hesitant to explore the area forward of the tank. I hate to not be able to match the test holes with the cockpit and they be visable. Prob needs to be done though.


Last edited by Snider on Fri Aug 31, 2018 10:04 am; edited 1 time in total
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Snider



Joined: 21 Jun 2013
Posts: 167
City/Region: Charleston
State or Province: SC
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Kestrel Dawn
Photos: Kestrel Dawn
PostPosted: Fri Aug 31, 2018 10:26 am    Post subject: Not to bad Reply with quote

So it's not as bad as I thought. Looks like now I just rout out the bad balsa and fill with thickened epoxy? Any tips on finishing it so that it looks like the hopes were never there? Even though most will be covered by the tank. Most holes only had about an inch of wet balsa, the exception being the enlarged hole where someone screwed down at an angle.

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hardee



Joined: 30 Oct 2006
Posts: 9982
City/Region: Sequim
State or Province: WA
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: Sleepy-C
Photos: SleepyC
PostPosted: Fri Aug 31, 2018 11:22 am    Post subject: Reply with quote

Brandon, Just looking through your photos. Looks like you are doing a good job. Question? Was there not a bilge pump on that cockpit sole, aft, between the tanks? I didn't look like there was. I think there is a "sump well" or depression there, midship, for locating one. Maybe I just missed it.

Harvey
SleepyC Moon


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Snider



Joined: 21 Jun 2013
Posts: 167
City/Region: Charleston
State or Province: SC
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Kestrel Dawn
Photos: Kestrel Dawn
PostPosted: Fri Aug 31, 2018 11:34 am    Post subject: Hardee Reply with quote

Hey Hardee,
There is a depression there and I plan to install a second bilge pump, either electric or manual. I have a sump to starboard of the companionway door. The rear bulkhead straddles it with half in the cockpit and half under the stove. Thereís a bilge pump in there.

The good news is that the screw holes for the battery hold downs and the port side tank were either dry or had less than a Ĺ inch of wet core around the holes.

The area on the starboard side around that problem screw hole is about 6 inches x about 2 inches in a linear fashion. At this point it may be easier and a better fix to cut the top skin off and just fill the whole area. Iím still working on it though and think I have the most wet stuff out. I may be able to let it dry out and just fill the holes Iíve drilled. I just want it done right.
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Snider



Joined: 21 Jun 2013
Posts: 167
City/Region: Charleston
State or Province: SC
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: Kestrel Dawn
Photos: Kestrel Dawn
PostPosted: Fri Aug 31, 2018 2:22 pm    Post subject: Done for the day Reply with quote

OK I'm done for the day. You can sort of see the outline of the wet core from the screw holes. The outermost holes were dry. I think I have so many holes drilled that I don't need to take the skin off. I filled the dry holes and I think I'll just re-screw the hardware down into the center of the epoxy plug and use 4200 underneath. Do you guys think that's a solid plan? The issue with glassing down the runners is that the forward partition sits and is screwed in aft side of the runner. So to take the tanks out you have to be able to remove that forward runner in order to pull the partition off as one piece. The tank sits up against the screws that hold the partition to the runner and it looks like that partition gives the tank a little forward stability so I want to keep it.

I also found some rubber liner at the Home Depot thats uses to line the bottom of showers, debating whether to put it under the tank for a little abrasion resistance. Thanks for the help and the forum, this place is a great resource. This repair, including 6ft of fuel line will end up costing just over $200


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ssobol



Joined: 27 Oct 2012
Posts: 1759
City/Region: Leesburg
State or Province: VA
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
PostPosted: Fri Aug 31, 2018 3:19 pm    Post subject: Re: Done for the day Reply with quote

Snider wrote:
...

I also found some rubber liner at the Home Depot thats uses to line the bottom of showers, debating whether to put it under the tank for a little abrasion resistance. ...


Mine doesn't have anything under the tanks. If they are securely attached, they shouldn't move so there should be no abrasion.

Look at the bottom of the tanks and the area where they sit to see if there is any evidence of existing abrasion. I don't see any in your pictures. You might be fixing something that isn't broken. However, if you feel more comfortable doing something then go ahead.

Just check that what ever you put under the tanks is gasoline resistant/proof. Don't want anything that will turn in to a gooey mess if gas does happen to get on it.
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capt. meares



Joined: 04 Jul 2013
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City/Region: Tillamook
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C-Dory Year: 1988
C-Dory Model: 22 Cruiser
Vessel Name: Vianey
Photos: Vianey
PostPosted: Sat Sep 01, 2018 12:58 pm    Post subject: Reply with quote

I did the same project 2 years ago. All my gas tank screw holes were dry and well siliconed until I got to the very last one. I found no evidence of silicone (maybe they forgot?) . This one screw hole had rot and moisture as far away as 12".

Dont think just because you do a light exploratory hole and find dry balsa on top, that you are out of the woods. The majority of mush I found was at the bottom, (pooled against the outer hull glass), and the area became smaller the higher up I explored. Similar to a funnel shape.
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thataway



Joined: 02 Nov 2003
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City/Region: Pensacola
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Photos: Thataway
PostPosted: Sat Sep 01, 2018 6:50 pm    Post subject: Reply with quote

In your case, I would just fill the holes and get some paint which js close to the bilge cover, "
Bilge Coat is a product frequently used. The "pattern on the bottom is basically rolled out thickened gel coat. I did replicate that pattern on the cockpit floor rolling it out.
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