This is not energy efficient. A better way would haven been to have mechanical latches, that are connected to the weights and which use the battery to unlatch

This is not energy efficient. A better way would haven been to have mechanical latches, that are connected to the weights and which use the battery to unlatch the locks. I am curious how the weights are wired, because you cant just run wires from inside the sub to outside. The pressure gradient is too high. So with mechanical cables holding the weights.