Originally Posted by Gray
If you saw this on your boat and it had bubbling water coming through the crack what would you think?
Just a guess here since I don't know how your boat is built internally, sure looks like the boat is bending/ folding due to wave pressure, engine torque on the transom, the stiffest point tying the hull and the transom together is exhibiting signs of stress first, the cracking will probably continue.. Do you run it pretty hard? If you are going to put more power on it you probably need to reinforce the joint between the two ( hull and transom). With no gunwale supporting it there is a lot of stress. That being said, I hope it turns out to be less serious than my speculation makes it out to be, good luck!