Hydraulic tests were conducted on the characteristics of motion of a buoyant caisson put on a semi-submersible lift barge to confirm the validity of a new caisson transporting and launching method by using a semi-submersible lift barge. It was found that the motion of the barge greatly decreases when it is semi-submerged, and that the motion of the buoyant caisson on the deck is influenced by the wave direction against the barge and the location of the caisson on the deck. Using these results, a safe launching method under wavy conditions was presented.
