Concrete ballast

[rbh1515]

I have been meaning to ask this for a while...and someone buying a new Com-Pac asked me about it, so here we go.  I was surprised when I found out that my HDC has concrete ballast.  I thought when I ordered it that it had lead ballast.  I suppose that they use concrete because it is much cheaper.  Do they seal over the concrete with fiberglass or anything.  Is there anything I should be inspecting over the years.  It's kind of hard to see down into the bilge on my HDC.
Rob

[alsantini]

Hi Rob. I think they have been using concrete forever.  A friend had an old 19 and said he never did anything about it.  It is totally encapsulated in fiberglass.  Hopefully, someone with "real" knowledge will chime in.  Sail on....    Al

[Gerry]

My 1981 CP 16 has concrete.  Never a problem.

[JTMeissner]

Not sure about the HDC, but older ComPacs may have issues.  Not sure if the old boats were fully encapsulated, don't believe my MK-1 CP-16 was, but overall, concrete seems to be a typical ballast across many different manufacturers so in general, not a big concern.

That being said, there are times it become a problem.  If your boat has sitting water in the bilge for an extended period of time, a winter freeze may cause issues.  If water has the ability to creep along between the concrete and fiberglass, freeze, expand, melt, and repeat, there are ways for intrusion to occur.  Get enough water low enough and a good freeze may burst through the fiberglass along the sides of the keel.

Another outcome, which is what I believe happened to mine, is the water got in, froze, thawed, but instead of bursting the fiberglass, the expansion and loose concrete forced the ballast to rise and it was no longer flush with the hull bottom.  A PO then just edged the raised concrete with some more along each side.

In this picture, you can make out the original concrete in the middle and then the side additions (which didn't adhere well), making a solid concrete surface across the bottom.  Towards the stern you can see the blocks of concrete I had removed previously, they were just loose chunks sitting in the bilge.


Chiseled out the additional side concrete, and you can see how the middle was above the "grade" of the fiberglass:


I've since taken most all the rest out, down to the bottom of the keel, mixed in some lead, and remixed new concrete.  It's not terribly difficult, but not a simple task if you don't have the deck removed.  I'm waiting about a month for the concrete to mostly cure before I work over the top surface.  Not sure if I'll layer fiberglass mat or just go with a resin seal.  


Lead, removed metal pieces, and a "non-mix" concrete in the bottom front.


Regular concrete mix to even out the keel, then topped with a non-shrink high-strength concrete grout.


Then after a few days of damp curing I let it begin to dry out:


So, not without some issues that can flare up.  But, keep the bilge reasonably dry, never let water sit and freeze, and I think there will not be a problem.  A boat that sits in NE for ten years being neglected is how you end up like this.

-Justin

[rogerschwake]

  A 27 owned me for about 7 years and in that time water found its way into the concrete ballast . Living in the upper  Midwest that water froze and did the poor boat no good at all. It caused some real bad boat pox on the keel. When I went to sell, it cost me big time to repair this before the surveyor would OK the repair. We ran 2 vacuum pumps plumbed to the bottom of the keel for 2 weeks to dry it out. Then dug out the pox areas and filled them and wrapped the keel with 2 layers of fiberglass cloth  and epoxy. Followed by new bottom paint. Also found where the water was getting in, in the bilge and fixing that and painting there also. If your looking at a boat that's be in a area that freezes  check the keel over real close.

ROGER

[Potcake boy]

To my knowledge only external keels are lead. I would guess that's because of the obvious problem of pouring molten lead into a fiberglass shell. Not certain why Com-Pac has always used internal ballast keels but typically external lead keels are high aspect fin type which equals deep draft. I've had a few Com-Pacs and the concrete seems to work just fine but I've never left one in the water year round. Not science, just my observations.

Ron