OK. That sort of damage suggests the boat hit something while in reverse. It looks like it is where the encapsulated lead keel is attached to the keel stub of the boat.
I would examine the keel area inside and outside the boat for signs of damage.
When hitting an underwater object, attached keels move like a fulcrum. Near the object, they move out and away from the hull, leaving a visible crack. On the opposite end of the keel, the movement is up and inward, causing compression-type damage.
Here is an image of a hull and the keel attachment for some perspective.