Author Topic: Aloha 28 Keel leaking calthemite like substance  (Read 329 times)

Now I Sea

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Aloha 28 Keel leaking calthemite like substance
« on: May 23, 2019, 06:49:22 PM »
Hi everyone, thank you for allowing me to take part in the group. 

Looking at a mid 70's Aloha 28.  Very concerned with whats going on inside the incapsulated keel. Boat came out of salt water many years ago and has been sitting in cradle with water weeping out through a drain hole filled with silicone.  Tapped the keel, all sounds constantly solid.  Although there are a few pounds worth of white deposit looking like something out of a cave under the drip.  I checked the fluid coming out with litmus paper and read a ph of 8-8.5, so mildly acidic.  My theory is the concrete is dissolving in the Keel. My main concern is the resin is too and the acid is caused by hydrolysis reaction in the epoxy resin :(.  Has anyone encountered this exact issue?  I have read on here the lead ballast is filled in with concrete, is this so?  How would you go about fixing this issue?  If you felt the keel is still sound and wanted to stop the hydrolysis reaction, is there any magic potion you can pour in there  ;D ?  Any thoughts or ideas are much appreciated. The boat also needs extensive work so a costly approach will not be worth it.

Jackrabbit

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Re: Aloha 28 Keel leaking calthemite like substance
« Reply #1 on: May 24, 2019, 07:28:41 AM »
PH above 7 is basic, not acidic.  Concrete is basic, so its possible that this is just the result of water coming into contact with the concrete packer, and is not necessarily the result of dissolution.  Not sure where the epoxy resin would be in your keel, as the builder would likely have used polyester.  Epoxy is fairly inert, so wouldn't be "hydrolysing".  Some boats, like the Alberg 30, were filled with iron tailings and bedded in concrete filler, rather than lead, in which case you would see rusty water weeping out.  Not sure whether this is the case for the Aloha, but in any event, the biggest concern here would be a water-logged keel freezing and expanding in winter, causing cracking of the fiberglass envelope.  Concrete is hygroscopic, so once wet in an encapsulated keel would likely never dry out.  This is a fairly common problem for any encapsulated keel with water infiltration, and unless there are visible signs of damage to the skin, I wouldn't worry about it - boat's probably been like that for years and still works, so just enjoy her.

bluenoser

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  • 1981 Aloha 8.2 "Whisper" Hull #50
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Re: Aloha 28 Keel leaking calthemite like substance
« Reply #2 on: May 24, 2019, 05:03:52 PM »
I had the same issue with my 8.2 about ten years ago. I found I had some voids within the encapsulation and water was reacting with the steel and concrete and oozing the substance you describe out through a few small fractures in the fibreglass (which I assume were caused by trapped water freezing). I sounded the voids with a small hammer and drilled a hole at the bottom, then one at the top. The water was allowed to drain over the fall/winter and in the spring I injected epoxy into the bottom hole until it came out the top. After the injection cured I fared the drill holes.
For good measure, I then added a brass garboard plug about 2" from the bottom of the keel and every fall, once on the hard, I remove the plug to allow any seepage to drain. I have had no issues and so staining since.
Hope that might help.
Work is for people who don't go sailing.

Now I Sea

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Re: Aloha 28 Keel leaking calthemite like substance
« Reply #3 on: June 16, 2019, 10:34:19 AM »
Hey Thanks guys! 

Jackrabbit your right on, I just assumed acidic because thats the only kind of litmus paper I'd seen. Found some in the tool box, but ya, for measuring bases  ;D

Sounds like a good idea Bluenoser!