If you look carefully there are two beam cranes that extend outboard from the side of the deck above. There are difficult to see at first glance because they blend in with the rest of the white painted parts of the boat.
Kelly, they use trolley or overhead cranes. Much in the same manner they are used when launching from a garage in the hull. It is the same process really, just no side garage shell door to open and close.
It is a good job of blending them in. You can see them pretty easily in the pic above of the starboard side.