Keel concrete advice

[_JP_]

So, (as was somewhat expected...) a small project has turned into a gigantic one. Just didn't want to slap some paint on her with all the rotten wood below, not to mentioned the deck/hull sealant and rubrail was shot as well... so off came the deck, out came the rotten wood, and now she's ready for the rebuild.

I'm questioning the keel design though.... While the central portion of the concrete keel is solid and dry, the top outward sides, where the concrete spills over onto the bottom of the hull, have cracked away and are long gone. I believe this is from the sideways force exerted by the keel. As the keel moves ever so slightly athwartships, the concrete is in tension and therefore splits. Then, we get concrete rubble for ballast.

So to fix, once stringers are installed and glassed in....

Option 1 (original plan):
Clean up all loose concrete and treat with bonding agent. Pour new crack resistant concrete (with acrylic fortifier) on top and beside existing concrete. After curing, cover with glass mat and epoxy. Hope it doesn't crack again.

Option 2:
Chip away concrete until it's below the hull. To mitigate flexing, install (3? 4?) 2x4 braces 90? between stringers (lag bolted and glassed in). Treat with bonding agent. Pour concrete between braces. After curing, cover with glass mat and epoxy. (Although this sounds like an excellent idea, the forward half of the keel wouldn't have these braces since it'd interfere with the portable head and legroom while seated on the bunks.)

Option 3:
Chip out entire ballast and repour. Use steel mesh in upper part of keel where it spills over onto the hull. After curing, cover with glass mat and epoxy. (I will be repairing and painting the hull. Bonus here would be that once empty, I could flip the hull and repair, rather than upside down on the trailer. Also, I would probably add 100 lbs lead at the bottom of the keel.

Option 4:
Cut my losses, give her away for the value of the trailer, and get a boat that's ready to go. It's gorgeous outside dangit, and I'm ready to get out of this house after two months of shelter-in-place!


Your thoughts please!

(I was so disgusted with this concrete issue that I passed on a deal of a Sovereign 18 once I saw that it too had a concrete keel (although the keel was in perfect condition). Looking back, i should've bought it, but was a little frustrated at the time.)

[Tim Gardner]

Go with option 1.  Epoxy grout rather than concrete to fill spaces.  JMHO  TG

[_JP_]

Epoxy grout looks and sounds promising, and I hadn't thought of that. Crack resistant, waterproof, and would look nice.

But cost? 5 lbs is about $50, so it's roughly $10/lb. I was estimating I'd need two bags (100lbs) of concrete to fill what's been removed between the stringers. 100 lbs of epoxy grout would cost approx $1000.


https://www.homedepot.com/s/epoxy%2520grout?NCNI-5

[Hutch]

Hello, JP!  I am in the middle of the same project as you.  I have already removed all the concrete ballast, and I have the hull flipped over to work on repairing the keel.  Take a look at the photos I have posted.  I found that most of the concrete was wet and brittle all the way down to the bottom.  Actually, it was easy to chip away at the top, then it became a little more difficult for a few inches, then it got easier again. 

Anyhow, I have been on pause for a few weeks, as I work on other projects around the house and yard.  Plus, the weather has been rather cold and rainy, so I am not yet ready to epoxy repair all the cracks and chips in the hull.  By the way, I already bought 450lbs of lead ingots and shot, to fill in the bottom.  I will epoxy it all in, so I will have a bilge to collect water in the end. 

By the way, I found 45lbs of scrap wheel weights in the bottom of my keel.

Cheers!

Robert