Re: I like this Sabre 28 BUT.....
The photos concern me too! I would bet that you have bulkhead rot judging by those leaks.
Can you get at them with an ice-pick and see if you can tell how bad. Or sound them out.
With the mast down and no tension on the shrouds, the hull might not reveal it. But if the rig were up and tuned, it could show dimples in the hull around any weak bulkheads.
With the floor, you'd have to open it up and see if the stringers were affected..I'm guessing so...
Cost to fix, depends on who's dong the work. At yard rates of $90.00/ hour you could be looking at a very hefty tab. If you do all the old removal, cut new bulkheads, grind out the old tabbing yourself you could save a few bucks. ( you might want to get a pattern from the old bulkhead before you knock it out)
Then you'd have to tab in the new. Chainplates could have some corrosion, you'd have to pull them to see. The core and deck could be wet and soft around the penetrations. You could sound that out now. I would be very careful, unless the price reflects the amount of potential remediation that you would be facing. The good news is, that if you were to do this work and everything else looks good, you would have a nice sabre.
Though, someone who let this damage occur might likely ignore a number of other things.
So I'd look everywhere. Caveat emptor.