1. The crack is between the deck and the headliner.
2. Around hatches these areas are often filled with polyester based putty.
While #1 appears to be true based on the image, your focus on the Hatch as the cause may not be actual.
The image appears to have been taken with the camera facing towards the companion way. There is no mast base located in the image. The question is one of hatch location. Is the hatch in question the one located on the ship diagram? If so the next question would be has the mast been removed?
The boat is located in the NE. In that region, removal of masts and boats happens during winter storage. The ingress of water may not be from the hatch alone. Water damage may be from the hole left by the removed mast and not covered properly over the winter. It could be damage from water between the deck and the salon ceiling that froze and expanded. All of these are undefined in the original post. Inspection beyond the hatch is warranted.
@marcham 
is spot on when he says: "Almost everything on a boat is fixable with time, interest to learn, and determination.