Because you missed in the same episode during that part where David Cameron said that Leo’s character dying was what had to happen. That was the story. It is a pointless gotcha, based on the movie not spending the time to determine the exact amount of buoyancy of a ship wreck.
Solar yes battery would be a problem from a weight stand point. That much weight that far out could cause acrwy things.
In the other hand hard say of the solar would be that useful for the cost to install since there is no guarantee it would be facing the sun correctly. Creating a deck cover of solar though could be useful.