Fiberglass Repair Advice on an 17' American Fiberglass

[bamidon46]

That's what's inside. It is DENSELY packed and goes well up into the lower part of the hull.

[jimbunyard]

If it was densely packed into the lower part of the hull during construction, and then sealed into the hull with a glass 'floor' to permanently keep water out, it could be there as ballast and it would also add considerable stiffness, as long as it was packed densely enough to preclude any movement whatsoever.

If so, now you're faced with the problem of how to replace it. Depending on the quantity and how you're repairing the boat, you could repair the exterior hull, remove the floor covering the ballast (if there is one), repack the sand and recover it. Good as new!

Or you could invert the hull, mix a relatively thin slurry of polyester resin and dry sand, pour it into the existing cavity, and repair the hull after filling the void.

Or you could just glass over what you have and hope for the best.

Or any of several other things...


I still find it very interesting, and unusual, that a manufacturer would use loose sand, even packed and enclosed, as ballast in a production sailboat.

[boatpoker]

Originally Posted by bamidon46

That's what's inside. It is DENSELY packed and goes well up into the lower part of the hull.

I doubt that it was installed as "Loose sand". Many boats, even high end ones used concrete for ballast. Over the years the concrete breaks down from salt water intrusion. I've seen the same looking material dug out of an Island Packet keel (plus some scrap metal).

[jimbunyard]

Is this your sailboat?

https://sailboatdata.com/sailboat/american-22-mini-ton

https://www.shortypen.com/?boat=45

If so, the ballast is listed at 300 lbs, though of what that ballast is made, I couldn't find.

If it is concrete that is the strangest concrete I've ever seen, no aggregate, and apparently the lowest portland cement to sand ratio imaginable.

Could be possible that the manufacturer home-brewed his 'concrete' (common enough in that era [in this case it's technically mortar]) and somebody messed up on the sand/cement ratio.

I've never seen saltwater 'break down' concrete mixed in the proper proportions, at least not to the point shown in the picture. Though some would say 'Anything's possible'...

I've had Quickcrete (premixed bagged dry concrete mix) from the factory with so much sand (or if one prefers, so little cement) that, when mixed with water, the 'concrete' never became concrete...

[Spot]

I am thinking that the boat is the old American Fiberglass 16.
The OP will have to chime in if this isn't right.



https://sailboatdata.com/sailboat/american-16
https://www.sailingtexas.com/cboats99american16.html

I was told on another forum that American Sail took over the product line in the 1970's. That person did not see any ballast in their research.

https://www.americansail.com/

[Spot]

Another reply, same forum, a person saw sand accumulate in a Laser dingy through damage to the hull/rail.

[bamidon46]

Hey everyone,

It is an American Fiberglass 2+2 mini ton. After digging myself I can confirm that what we're seeing is old concrete that was poured in the hull as ballast. What I think happened is there was water leakage into the hull amd with the freeze thaw cycles of upstate NY winters it broke up the bottom layers of concrete. That's the only stuff that's loose, it's still formed and dense after the first few inches. I think it also caused expansion which is how I got the cracks as well as they are straight and along the bottom of the keel.

I've gotten some recommendations and I think I'm just going to get a bag of quikrete or sakrete, mix it, and fill the void that's been left in there. My reasoning is mostly to keep the ballast weight about even as 20-50lbs have fallen out. After that I'm going to use West system and patch each hole and use a thick structural filler. Then sand it down and paint the hull.

After removing the swing keel itself water dripped from the screw holes. Any recommendations on something I can pit on those when I screw them back in? I initially just think silicon caulk meant for water use... But you'd all know better.

Anyway, thanks for the advice.