I also had to drain the water from a cement filled keel on my Albin.
Boat was on the hard so I dug a hole in the bottom of the keel under where the water was seeping out (by the stern tube) and tapped it to 1/2 NPT.
Immediately the water stopped seeping near the stern tube and drained out the bottom tapped hole.
I let the water drain until it was launch time, then I bought an allen head bronze pipe plug and applied a liberal amount of 5200 on the threads and over the plug.
(It took 3 winters on the hard to drain all the water out, but it finally did stop.)
Once I launched the boat after the initial plugging, I carefully inspected the bilge and found the culprit. The original bilge pump was screwed to the bilge floor and the holes were never caulked. I glassed over the holes, then re-mounted the pump without fastening it to the bilge floor.
That stopped the leak.
New Port Richey,Fl