Mysterious bilge water


New Member
I put my new to me J24 in the water on Wednesday. It's Friday afternoon. The bilge was about half full. It did rain pretty hard, so at first I wasn't to concerned. But then I tasted the water and it was brackish. So I suspected there was a leak from below mixed with some rain water.

There is a drain hole in the back of the bilge on the starboard side. That's the source of the very slow leak. Where does that drain hole come from?

Pics attached


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I don't offhand know what you have there or what's happening. But I'm a bit curious. My boat is quite early, '78, and had the vermiculite-cement filled keel stub and bilge. When that stuff was removed, the keel sump was mostly filled with a resin mix. I'm not really knowledgeable about how the later boats were built. I suppose I've seen them, but don't remember. But I think I'm looking at a keel sump that's not filled with anything, is that correct? Top of the photo is forward, and you've got a hole a couple of inches down at the rear stbd corner? Hmmm. Could it somehow connect to the bilge under the sink or berth on the starboard side? If you stick a wire in there, how far can you make it go?

How do you know that the water came in slowly, and through that hole? If it's seawater getting in there, there would be some obvious problem with the keel from an exterior examination. It shouldn't have been hard to see. There may have been some dried seawater in the sump leaving salt to combine with water from some other source. Maybe it's rainwater. It could have come down the mast; even through the halyard openings. Bail it out before a forecasted week of nice weather and see what happens.

My early boat used to leak like mad at the toerails... the hull / deck joint. When it was built they did not use (maybe didn't exist yet) polyurethane adhesive caulks. It was just bedding compound, which is something like talc in linseed oil. One winter when it was sitting in a boatyard 2-1/2 hours away it took on 75 gallons. (!) Re-doing that was one of the most rewarding things I did on the boat.

What's your boat number; when was it built?

Final thought: Maybe that hole just allows any water accumulating under the floor aft of the keel to make it's way to the sump. I'm thinking that's most likely. I think at the bottom of your photo there's a bit of a bulkhead that might otherwise prevent that from happening.


New Member
Hi Vince,

You are correct, in that it is the bilge and the bow is towards the front of the picture. The hole in the rear seems to be a limber? hole for draining from somewhere.

I think I might Infact stick a wire up there to see if I can ascertain where it leads. I'm fairly certain the water is coming in through that hole and no the keel bolts themselves.

The boat is 2515, it's a 1981? I have no idea if it use to have vermiculite or not, seems to be near the transition period?

The hull was in immaculate shape when I launched it, several people happens to look it over, that being said I wasn't concentrating on hair line cracks near the keel, I probably should have.

I have about 1cm of water in there each day I come back. I can see a drip from that hole run down into the bilge periodically. The water tastes brackish. There is slightly more on rainy days, but I just sealed off the mast yesterday, so that hopefully won't be the case anymore.

Interesting about the fresh water dissolving salts, you aren't the first person to mention that. I got the boat from the Great Lakes, bit I can't say for sure that it was always in fresh water.

I'll try and figure out where the hole goes and post back here.

My best guess at this. Point is that there is a hair line crack between the keel and the keel box and water is squeezing in.


Well I'd say it does sound like it's seawater. If it's been living on the Great Lakes, I don't think it would be brackish. Sorry to hear that. I don't really have other thoughts. But I'll show you what our bilge looks like 20 yrs after the vermiculite was removed, keel floors (lateral stiffeners) were installed, and the sump filled. It looks like your photo is of the center section of the keel only. I'm guessing it was originally that way. I agree that your boat is probably in the approximate time-frame when stopped using the vermiculite cement, but I don't know exactly. Your boat hull number should include a month and year of build.
Keel and bilge.jpg


New Member
Thanks Vince,

I would like to replace my cabin sole in a similar fashion with a wood floor supported by the lateral wood/fiberglass stiffeners. Is there as rule I would break in doing so? I might as well while I diagnose and fix this issue.


Reading the rules, I believe so according to section D 2.2 (a). But I feel sure that it would be fine, if that makes any sense. Like our initial interchange.

At least 2000 of the 5000+ boats built had the vermiculite problem, and many of them have been repaired. So measurers and others expect to see plywood cabin soles on old boats. D2.2 (h) makes mention of modifications made during the vermiculite repair. The measurer spent no time questioning or examining the repair that I did. has an article on pg. 15 that describes that repair. The writer talks about 3 'floor frames', but I was supplied with 2 in the kit I bought from TPI. I installed them in '96, but went back and re-did the fiberglass tabbing bonding them to the hull, and then added a third one that I fabricated in 2004. The new one is in the foreground of the photo attached. I made it of 10 or 12 layers of 12 oz. cloth. There should be other articles, but I don't recall where they are, and I haven't re-read all those archived magazines.

I am kind of surprised that your sump doesn't appear to be filled with resin. With the end of the keel bolts down in the sump though, that's an impossibility.

The old magazines in the archive are pretty useful, even if some of the info has been superseded.

Still, you should be familiar with the rules, available here:

This keel floor in the foreground later got 4 overlapping layers of glass cloth tabbing epoxied to the hull, like the one under the vacuum hose.



Active Member
Question about removing the vermiculite, how far down does it go? I never have seen anyone show pictures on how deep to dig out, or how far sideways under the floor does it go. Also, does it go past the ice-chest/step area? Curious since I will have to chisel mine out at some point and don't want to go too far. Is there a way to tell so I don't go through the hull? Do I just want to get rid of the material that is cracked and just make sure there is a stable foundation since a few inches of epoxy will be set on top? Thanks in advance.


It fills the sump, which is the interior of the keel stub which protrudes from the hull. The keel bolts up to that. So if you were to look at the keel when the boat is out of the water, the top ~6-1/2 inches of what you're looking at is the fiberglass keel stub. So, it's about that deep on the inside.

I think that my vermiculite removal was very successful. I don't know what I had for instructions at the time (1996), but I had some, I feel sure.

Keep in mind, you're hearing from just one amateur here, not some pro. I've learned a lot about boatbuilding and repair over the years though, and I don't think I'd do anything differently with this job, other than do a better, more precise job of glassing-in the keel stiffeners at the outset.

The vermiculite mix extended to the berths on each side, and back to about just under the companionway opening. My floor was cut out a bit aft of that. We chiseled it out with an electric hammer drill with a chisel bit. If you do it at a low angle, you know when you contact the hull on the inside. You'll probably do a little damage that needs some repairs, but it's easy to do. The stuff extending out past the keel area was not replaced with anything; only the sump was filled. I think that was the 'standard', at least at the time. You may not really need to get all of it out beyond the keel area, but what remains wouldn't be doing any good. You DO need to install "keel floors", floor supports, or whatever they might be called, to spread the load of the keel out into the hull. The original idea of filling the keel and lower part of the hull with the vermiculite cement was to turn the entire assembly in to a monolith.

If you plan to race the boat, you might contact a class measurer to find out the latest approved method for doing this fix. But you may not want to find out.
There's some indication (here on Sailing Anarchy: J24 sump...epoxy or polyester resin filler? that there might be some updated more "official" way of doing it, but I don't know. I don't find it at the US or International Class websites. There's a lot of discussion on that Anarchy thread, but I personally think what some are discussing is overkill in a big way. This isn't rocket surgery, you know :)

Good luck. But go sailing, and work on speed. The faster you go, the easier the tactics and strategy are.


Active Member
Man, I really appreciate the in+depth reply, the most I have ever had about the questions I posed. A fine dram in your honor is tasting a lot better as we speak. Cheers!


Active Member
A couple of interesting take aways from reading all of the sourced articles (thanks again for sourcing them) and others I could dredge up on the inter-webs: 1) Vermiculite is a material, just like epoxy, I am not convinced that vermiculite was able to handle the lateral loads of the keel when healing, thus water getting into the sump in the first place. Since the J archives articles are from the late 80's, I don't think they had a good grasp on what 21st century epoxy/resin can handle in terms of load, flex or shrinkage. It doesn't appear that those who performed a "verm job" with resin/epoxy only, and no lateral supports, have any leaking or water entering the bilge (not that that is the only reason water enters the bilge). You are spreading the epoxy wide enough across the floor of the boat and into the sump, and thick enough ( with chop/strand/filler) to reduce flexing and lateral movement of the keel bolts, so I'm not convinced stringers are necessary, as evidenced by those who do not have any. I agree that additional support of any build can be beneficial (using 2X6 studs versus 2X4), and the best argument for using stringers would be to support the new wood floor.
I don't know what modern > #45xx model J's have in place of this, but it would be interesting to know if they are adding stringers in that section to provide lateral support for the keel. If not, then either the lateral load displacement is not as much as they thought or the newer materials in construction are far superior and provide a solid base to attach the keel to.
2) Replacing the cabin floor with wood, if stringers are added, why isn't anyone just using the old floor and epoxy'ing the edge back in? I get it that using screws is easier to attach a wood floor versus mixing up more epoxy/gel-coat/whatever, but it would sort of restore the boats original features.
Just some thoughts.


New Member
I bought a borescope to check out that limber hole in the back of the bilge. Turns out it's sealed off and only about 1" deep. The leak is definitely coming from within that hole.

I'm considering trying an epoxy putty to stop the slow leak until the fall when I can investigate out of the water.

I'm more and more convinced there is a small crack in the back of the bilge.


New Member
I took the boat out of the water last week to give the bottom a cleaning and reapply some VC-17.

First note. The VC-17 performed well for me in salt water in Nova Scotia. I had a couple spots of barnicles, but in both cases the VC-17 failed there and the gel coat was exposed. So I plan to re-prime and sand those areas to get better adhesion.

As far as the bilge leak goes. I scoped the limber hole a month or so ago and it's blocked 2" back by fiberglass. So I used underwater epoxy weld and sealed the hole off. That stopped the intrusion of water in the short term.

When cleaning the bottom of the hull I noticed 2 water blisters on the port side at the hull keel joint.

I started investigating and eventually ground away most of the fiberglass around the hull keel joint and replaced it a a crack had developed and water was cause delamination in those 2 spots. I got to good fiberglass pretty quick, so that's good.

Also on the port side there were crack in the keel where water had frozen between the fiberglass and the lead. I also took the time to remove that damage and reglass it.

Finally when I was finishing the sanding and fairing job I noticed the trailing edge of the keel at the very top was weeping ever so slightly. I wiped it dry and it wept again. I found my mystery bilge leak! I think? Go I ground out the crack in the keel up into the hull and used epoxy and 406 silica to repair.

I'm sure my keel is slightly thicker than the minimum now, but I'm okay with that.

Just a little more sanding to do and she'll be ready to splash again.


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I guess you're talkin' to me. Very proud of my bilge :)

The floor just screws down onto the athwartships supports ("keel floors") you see, like in the April 28 photo with the vacuum hose. Those supports. It's not glued. I pulled the teak floor out numerous times, to re-varnish it, to paint the bilge, etc. That's one item where it's good that it's 'reversible'. No need to make it permanent.


New Member
Awesome!! Thank you for the information. I'm in the process of purchasing a J/24.
It has some little things I'd like to do and then spend as much time sailing / racing and enjoying time on the water.


New Member
I'm in Connecticut. Hopefully out of Niantic Bay Yacht Club. They have a small, 5 or 6 boat fleet there that races Wednesday nights. There is a strong PHRF fleet in the area for weekend racing as well.