Skipperdude, on the pics i put up, on the one with number 1, 2 or 3 on it, where is your leak coming from? 1, 2 or 3? If it's from 1, you need a haul out. The previously mentioned caulking 'quicky fix' won't help a tube that is cracked from the back at the hull joint. (at least not for my money) Well, 5200 may buy you some time, but if it's the tube to hull fiberglass joint that is failing then you have a larger job to do to refasten the tube into the hull. Its one thing if the tube it self is worn or cracked.
If it is the tube to hull joint, if you have access to the entire way around the tube you could slap on some more fiberglass and beef the connection up from inside the boat. But getting it to stop leaking to actually put more fiberglass on is the trick. It would involve a dive outside, and sealing the shaft cutlass bearing and any water weep holes with beeswax (toilet bowl sealing ring works well,) and letting the wax get pushed in by seawater pressure. Then using a vacuum to suck up the water, and then acetone to dry up the remaining dampness. Acetone is very explosive. Air out the bilge the entire time with blowers.
You have to understand, the leak is small now. Something is failing. If it completely cracks, and overwhelms the bilge pump (and batteries) the boat will sink. That's about a 2" hole in the hull.
If you didn't align the engine reinstall correctly, it could have whacked the stern tube enough to crack it. Is there a boat repair yard near you? The 'why' it cracked is worrysome to me. If you don't figure out the Why it will likely happen again. And you know it will happen in the winter in AK......