J/30 Class Association

Leaking Keel Bolts

Posted By: JBiermann

Leaking Keel Bolts - 09/05/13 09:15 PM

Hi All,

As if there weren't enough projects to keep me busy, it seems Im taking on the extra water in my bilge through the bolts. From what I understand, the fix to this is dropping the keel when I pull her in a couple months and re-bed and re-bolt the keel. In the mean time I got some waterproof epoxy putty I was planning to press in along the nut and washer to stop/slow the leak (I'm getting maybe 2" in 24 hours?). Should I be worrying about anything structural? Should I re-torque the bolts (and if so what are the torque settings)? Has anyone dealt with this before? Thanks

-Josh and Marly
Posted By: Cap'n Vic

Re: Leaking Keel Bolts - 09/06/13 12:49 AM

some of the owners fixed the leaking keel bolts by grinding off a couple of inches of gel coat each side of the keel joint ... applying west epoxy and two layers of light weight matt basically sealing the joint from the outside ... then borrow a set of templates to make it work.

it depends on whether you believe this boat is a life time investment.

You would not believe the shape of some of these keels if you striped them down to the base lead and looked at voids, holes, gouges, and repairs over the last 30+ years.

when the boat is pulled see how bad the joint looks, it may just be one small spot that is causing the leak.

rebeding the keel can be an engineering job.
Posted By: Conundrum

Re: Leaking Keel Bolts - 09/06/13 02:16 PM

I have keel repairs in progress. Grinding away glass to repair cracks in keel joint revealed a large space between bilge and lead. The light area is space filled with glass and I presume resin. I found this space interesting and measured my depth to assure it is correct. Vic is correct about the voids from original construction. They are many. Also along the core and keelson joint. Repairs will make her better than new. My repairs are the result of grounding, not leaking
Good luck
I can't add the pic here. ,(Iphone). I'll send it to Bill to add
[Linked Image]

[Linked Image]

Attached File
keel1.jpg  (2860 downloads)
Attached File
keel2.jpg  (2304 downloads)
Posted By: JBiermann

Re: Leaking Keel Bolts - 09/06/13 03:53 PM

Alright,

I guess the first step is to figure out where and how extensive the crack is that's letting in the water. The surveyor told me that the J has a two part keel and I did notice a hairline crack the seemed to extend from one side, across the leading edge of the keel and along the other side about 18 inches back about halfway down the keel which the surveyor said was just a stress area where the two halves of the keel meet. Would this be a likely spot where water could be finding it's way in?
Posted By: Mark

Re: Leaking Keel Bolts - 09/06/13 04:58 PM

My keel repair work looks remarkably similar to Conundrum. Fixing the junction at the tail of the sump to hull connection because of a grounding. I've ground mine down quite a bit more though. I'm recoring around the keel and planning a full fairing job.

There is a 1/8 to 3/16 inch of material between the bottom of the stump and the top of the lead. The filling in the sandwich. A few voids and some areas of separation between the "filling and the bread." I'm sure this could let quite a bit seep into the sump if the "band-aid" around the sump to lead joint has loosened and produced "keel-smile."

I really don't see a reason to drop and rebed the keel. The sump and bolts are very strong for the size and weight of the keel. Overbuilt like many other parts of the boat. I'd strip the joint down to the molded sump and lead and do a G-Flex keel-smile repair. retork the bolts to spec when that done. That's what I'm doing anyway.

The sump was molded into the hull in the original layup. It is in two parts just like the hull. the outer "skin of the sump is nothing more than mat and two layers of woven roving. This is laid over the inside of hull laminate skin on both sides with hull core on top of it. Most of the sump thickness comes from when they tabbed the sump in over the inner skin when the hull halves were put together. The sump is 7/8th thick on the sides and 1.25" thick on the bottom. Half that is probably more than enough (my opinion but I am not a marine architect). There are plenty of boats floating with much less sump thickness and more lead.

Anyway, the crack you're seeing is from the joint at the outer skin of the sump where the two halves come together. There can be voids at the joint. It's not structural if that's all it is. When I stripped the gelcoat of my bottom I found a void at the center line hull joint running all the way from the front of the sump to the bow. Void as in air.
Posted By: Rhapsody #348

Re: Leaking Keel Bolts - 09/06/13 06:13 PM

Mark,

Are you recoring around the keel from the outside, or are you cutting the floor and doing it from inside? This is the last of the below the waterline areas I need to finish recoring on Rhapsody. Similar to the other posts, the aft keel joint to the hull has been stressed by past groundings and was only patched. It really needs the permanent fix. I intend to cut the area out and reglass this winter similar to the Conundrum.
Posted By: Mark

Re: Leaking Keel Bolts - 09/07/13 05:22 PM

Bill

I had damage at the tail and a bad repair that went through to the inside. I recorded and rebuilt the aft part, from the last stringer back on the inside. I don't think this was necessary, but I did get rid of the vermiculite this way, all of the nasty stuff is gone. Also my floor was squishy, all of the balsa core was bad.

The rest of the recoring around the keel is proceeding from the outside. Relatively speaking, the inide structure is massive compared to the outer skin around the keel. The inner tabbing is about a half inch thick and extends about 18" to either side. Then there'd be stringers to rebuild. About enough inside that the core and outer skin aren't structurally necessary.

The outer skin around the keel has three layers of roving for about 6" out, two layers out to about 12", and one layer beyond that. Much easier to rebuild the outside than the inner structure, even fighting gravity.

I'll post some pics of dissected pieces in my blog.
Posted By: JBiermann

Re: Leaking Keel Bolts - 09/08/13 02:16 PM

For the rest of the season I'm thinking that i'll suck the bilge dry with a shop vac and put some epoxy putty around the bolts to try and slow/stop the water. Should I re-torque the bolts before I do that for piece of mind? Or should I just let it be for now on all accounts and rig up an auto bilge? Thanks!
Posted By: Mark

Re: Leaking Keel Bolts - 09/08/13 05:55 PM

I don't see any reason not to check the torque on the bolts. Only tighten, don't loosen.

I would not seal them with epoxy. They are wet with sea water. Sea water minus oxygen can do bad things to metal, even stainless.

I'd get a good bilge pump and keep her plugged into shore power or get a solar panel.
Posted By: JBiermann

Re: Leaking Keel Bolts - 09/08/13 08:52 PM

That's something I hadn't considered but currently the bolts are submerged under a layer of seawater anyway as my bilge pump still leaves an inch or so on the bottom when the impeller runs dry... is access to the air beneficial to that situation somehow? I guess an auto-bilge might be the way to go.
Posted By: Mark

Re: Leaking Keel Bolts - 09/08/13 10:34 PM

Sealing wet keel bols just seems like a bad idea to me.
Posted By: JBiermann

Re: Leaking Keel Bolts - 09/18/13 12:18 AM

So there has been a disturbing discovery, keel bolts might not be to blame after all. There is a steady trickle of water coming from the seam at the very rear of the bilge cavity under the floor about where the hoses stick through (see picture). Any idea where the fault may be? Best way to fix it? I used some of the epoxy putty to seal the seam but water is still flowing around the sides, enough to trip my autoswitch about every 15 mins. Anybody seen this before?

[Linked Image]

-Josh

Attached File
bilge leak rear.JPG  (1204 downloads)
Posted By: Phil

Re: Leaking Keel Bolts - 09/18/13 12:43 AM

Check your stuffing box.
Posted By: JBiermann

Re: Leaking Keel Bolts - 09/18/13 12:55 AM

stuffing box is all set, I've tightened it up. I can see the water running in from that joint in the photo, where do those hoses run/ whats on the other side of that seam?
Posted By: Cap'n Vic

Re: Leaking Keel Bolts - 09/18/13 01:17 AM

only through hull on starboard side back there is water intake for engine, but you may want to check also the transom through hulls as they have a tendency to crack at 30 years. although only the exhaust is low enough to maybe leak at mooring. but there is a ~6 in. piece of hose with two hose clamps to check as well on the exhaust. If I remember correctly if it is leaking it will not drain down directly below the engine but through the starboard quarter berth or below that false floor you see directly under the engine.
Posted By: JBiermann

Re: Leaking Keel Bolts - 09/18/13 02:10 AM

engine intake through hull is dry, compartments under aft berths are also bone dry, engine compartment is dry as well and the stern compartment next to the transom and hoses, including the exhaust, also intact and dry. I'm thinking there must be fiberglass damage from previous groundings, somehow water is getting in along the keel and following the fiberglass up into the space behind the bilge where I cant access without pulling up the floor (unless someone has some info on this?) My plan is to pack all the seams behind the bilge with epoxy putty and assess when we pull her next month.

Posted By: Mark

Re: Leaking Keel Bolts - 09/19/13 02:04 PM

Packing those seams is just going to create a dam with a lake behind it. There's about 100 pounds of vermiculite back there under the floor. When I tore it out I found that some of the inner hull skin under the verm was porus, allowed water to leak into the balsa core. It's not a good place for a lake. Let the water drain into the sump and pump it out.
Posted By: JBiermann

Re: Leaking Keel Bolts - 09/19/13 02:09 PM

What is the purpose of the vermiculite? What is the best way to remove the wooden floor, im guessing drilling out the bungs, removing the screws and carefully preying it up?
Posted By: Mark

Re: Leaking Keel Bolts - 09/19/13 06:07 PM

Josh,

I posted some pics for you in the photo forum:

http://j30.us/ubbthreads/ubbthreads.php/galleries/15207.html#Post15207

The verm supports the floor like the joists in your house. It was used instead of traditional stringers or "floors" because the floor is a molded part of the liner. It was set in all at once, squished onto globs of verm under the floor. The verm form fit into place.

The floor is a fiberglass laminate with a 1/4" balsa core. The floor was molded together with the liner (galley, cooler, settes, engine pan, etc.) all at once. Then all set in and tabbed where they could reach. It's under your teak and holly.

The verm aft of the keel sits in a low spot that can collect water. Your water is flowing through there from somewhere.
Posted By: NaturalHigh

Re: Leaking Keel Bolts - 09/25/13 02:29 AM

I had a steady leak like this and was coming through the prop strut mount. You can't see it because it gets under the liner right away and makes its way to the bilge. I suspect this is your problem.
Posted By: JBiermann

Re: Leaking Keel Bolts - 09/25/13 11:07 PM

Thanks, I'll look into it. What did you have to do to fix it?

-Josh
Posted By: NaturalHigh

Re: Leaking Keel Bolts - 09/26/13 01:11 AM

I actually through drilled the bolts to the inside, and glassed over the strut base. In hindsight I may have gotten away with just bedding them well, fairing, and a good epoxy primer, but I don't regret my decision.
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