What is my encapsulated ballast set in?

[xxxxx]

Hi folks,

My boat is an Alberg 30, which has an encapsulated iron keel.

I have exposed my ballast. The iron ballast is centered in the keel cavity / keep aperture.

Between the fiberglass keel walls and the iron ballast, there is some sort of aggregate / masonry / cementitious material.

It is also used aft of where the ballast ends to fill the remaining keel void, as shown in the photo.

It is damp right now from water (and oil) which leaked from the bilge, and it is fairly soft. For example, you can dig into it with a screwdriver if you use enough effort.

To me it seems like maybe a clay/sand mix.

At it's lowest point, the material is about 1" below the top of the iron, and I'd like to fill it up flush prior to closing it off with new fibreglass.

Does anyone know what it might be?

If I can't determine with certainty what it is, what might I use to bring the level flush with the ballast? I was considering either foam or sand mix cement.

(To deal with any trapped water, I've drilled a hole at the bottom of the keel for a garboard drain.)

[coopec43]

Have you looked at these threads?


https://www.google.com/search?ei=LOS...TvuCUAQ4dUDCAs

[xxxxx]

Originally Posted by coopec43

Have you looked at these threads?


https://www.google.com/search?ei=LOS...TvuCUAQ4dUDCAs

Yeah I've actually been searching for a while before asking. Also tried contacting the A30 group.

There is one post which mentions it might be vermiculite. I'm hoping someone knows with certainty. I've come across a lot of vermiculite in my days--none of it looked like what's around my ballast. That doesn't mean it's not, though.

And if I can't determine what it is, hopefully more knowledgeable people than I can suggest an alternative.

[Orion Jim]

Try using a hole saw to get a core sample. They come in various depths and diameters. Leave guesswork to the experts.

[xxxxx]

Quick update for future google searches who find themselves in the same predicament.

I was unable to determine with certainty what the material was.


I've decided to chisel and scrape it all out and replace it. Using a 36" long section of flat tool steel 1/8" thick x 1-1/2" wide, I was able to get all the way down along the ballast to the bottom of the keel cavity.

Then flushed with water. Then pickled with phosphoric acid applied all the way down using a garden sprayer. You can get Phosphoric Acid at your local hydroponic shop. Get the 75% stuff and dilute it down as desired (I've done multiple passes with 20%).

Then, dry with methyl hydrate (because it's cheap), and then dry with acetone (because it's more effective).


Then coat the iron, and back-fill with something. Not sure what yet.

[Frankly]

The specialty in the bag concrete people make special high strength mixes for pouring concrete counter tops. Fixed some outside bar tops several years back not even a hint of a crack.


Frankly

[xxxxx]

Originally Posted by Frankly

The specialty in the bag concrete people make special high strength mixes for pouring concrete counter tops. Fixed some outside bar tops several years back not even a hint of a crack.


Frankly

Thanks for the suggestion Frankly. That concrete is reinforced with chopped fiber. Super strong, resistant to cracking, etc.