Balsa core

I have been offered an 84 Freedom 35, built in the UK, She has been stored in a barn for approx 20 years. It appears she was halfway through a refit when the owner died.
Price is going to be very low due to the awful logistics of where she is stuck, no road access etc etc.
This does not really faze me nor does the woodwork as i am a boatbuilder. Main worry is the core, it looks like she has had core problems down near the keel with seacocks removed & glass ground back. Also several holes that have been drilled & epoxy injected this near the aft companionway low down in the keel sides.
Also a few forward in the frd cabin.
I have asked the current owner if i may take some core samples from the inside but the Question i would also like to know is did the builders extend the balsa core downwards into the keel area itself? ie under the ballast?
Also how is the ballast made up? leadshot cast in or pigs packed in? Any pointers will be useful in negotiations if nothing else!

I

I have USA built Freedom 28 (UK 30) Same design, just a bit smaller.
I can trace a line between cored and not cored parts of the hull very easily. There is very well defined ridge on inside of the hull where the thickness changes. Generally it is on the same level as a cabin sole. If you look on outside it is somewhere in the middle of inverted curve of a wineglass. There is no core in the keel/ballast area. If you look into this thread there is a pic of new core in port quarter. The core terminates down where the original core ended. Below is a solid fiberglass
http://freedomyachts.org/viewtopic.php?f=64&t=10462&start=10
I have ballast in a centerboard, there are lead cast down in the hull, and I also have loose lingots glued to the hull next to the centerboard under sole.

Thanks for that, that is what i was hoping for. It would seem that there may have been voids in the ballast aft therefore the epoxy fix.
I have asked the owner if he wouldnt mind me taking some core samples with a small tank cutter from the inside. Combined with moisture meter & hammer testing it will give me a good idea how far the damage went. At present externally the boat looks like a wreck but under the grime & cobwebs of 20 years appears to be largely in good condition. The interior is partially stripped out as the previous owner was in the process of swapping the galley for chart table when he fell ill.
The head linings are history & she will need a total rewire & plumbing too.
Plus side is she was not old when she was retired. Its a fair old project but my son & i are up for it, the other half is not impressed but she may come round!