Water leak

[Donmorrison]

Ok guys, I need a little help! I have a 91 marada, with a 4.3 cobra motor. The boat was running great the last time we took it out, last year. I winterized​ it and stored! Today we went to the lake and noticed a sound coming from engine compartment and when I looked there was water pouring from the bottom left of exaust manifold! What all could be causing this? Thanks in advance for your input! Ok upon further inspection, I have found the source of the problem, and 2 in crack on the front bottom of manifold. Can this be welded or is there something that has caused this to happen?