I'm no expert on this but my Fox looked very similar when the hull blew up on it. On the Fox I was able to remove the top cap and get inside for the repair. I purchased a new topcap and dagger well and replaced them. My dagger had broken in the hull and sheared up at the break point. It would appear that the diagnosis of the board slipping into the well is the most likely cause of this damage if the board didn't snap. Does the Stealth have a topcap that could be removed instead of cutting a hole in the hull?