My Albin has a cement filled keel.
It had water in it I bought the boat and the surveyor did not find it.
It was late fall when I bought it so the boat stayed on the hard at the marina where the PO had kept it for many years.
It was not until the spring that I discovered it dripping water out of a small "crack" in the gelcoat. The only way I could get to stop leaking and fix the area was to drill and tap for a pipe plug so the water would drip/ooze out thru the hole. It was still oozing out at launch time so I used a flush brass plug in the hole.
Every fall I remove the plug and let anything remaining ooze out. It took 4 winters of that until water no longer oozed out.
I DID find the source of the intrusion the first spring. There was a bilge pump (looked oem to me) that was screwed into the bilge and water was leaking thru one or more of those holes. I glassed up all the holes and mounted a new pump a different way so I wouldn't have to breech the keel.