Hull crack— how does this happen?

[Kettlewell]

and it definitely looks like the fiberglass is delaminating unfortunately

Ice damage? Where is the boat located?

[Don C L]

Well, it looks like fiberglass mat that has a layer of roving over it, that separated to me. Since it was hauled was there any time when you had freezing temperatures?
My friend who has a Cheoy Lee of the same vintage has considerable layers of mat as well. If it had not been saturated with resin and water was able to soak into it and freeze that might explain it.
And the water may have been fresh water that came down from the bilge, which is easier to freeze than salt water.

[Don C L]

Here's something I'm curious about, mix up some water and baking soda and spray it in there to see if it really bubbles up. I say this because my friend's Cheoy Lee had some issues with osmotic blistering happening in the mat layer but not too deep. (The osmotic process produces an acidic liquid in the blister.) When I saw it I was surprised that that would happen inside the mat; it seemed to me the mat should have been saturated enough to prevent any water incursion. I have heard that often times boats will show no blisters when first hauled out but they appear after a while. (Granted, I know I am suggesting this may be the world's largest blister.)
BTW I am pretty sure the ballast is lead.
The good news is, at least if my friend's boat is any guide, the hull is very thick!

[Mr. Kevin]

That was dropped or ran into something below the waterline with the keel. Very strange.

[Justo29]

Originally Posted by Don C L

Well, it looks like fiberglass mat that has a layer of roving over it, that separated to me. Since it was hauled was there any time when you had freezing temperatures?
My friend who has a Cheoy Lee of the same vintage has considerable layers of mat as well. If it had not been saturated with resin and water was able to soak into it and freeze that might explain it.
And the water may have been fresh water that came down from the bilge, which is easier to freeze than salt water.

It’s in the carribean so it’s definitely not freezing. It was on the hard for four years before I bought it. Had zero signs of hull issues. We had it in the ocean for 5 months and this has happened about 1 1/2 months after hauling out. We did have an impact during that time but it was above the water line on the end he of the deck on the toe rail. No wear near the damaged spot and the spot definitely wasn’t there when we hauled out.

[wyb2]

My guess (and that’s all it is): it’s large but shallow, I’d think an old (or not so old) repair that wasn’t bonded well.

[s/v Jedi]

Which boatyard is this? Cape Marina?

Need to pull this off and look under. Also look in the bilge/keel sump inside.

[Searles]

Is that damage under the mast step and is the mast still in the boat ,that looks like delaminate chopped strand grp no sign of double bias or ather heavy glass ,would guess rusted iron ballast with no support ,more info plus’s more fotos ,may reveal much more ,grinding it all out is a good start ,⛵️⚓️