METHOD AND DEVICE FOR INSTALLING CAISSON

PURPOSE:To make installation accurate by a method wherein water is injected into two base ships connected by a beam at an interval, two wire ropes are fixed to a caisson, the base ships are floated, the caisson is moved to an erection location and water is injected and the caisson is installed. CONSTITUTION:Frames 4 for supporting a beam are disposed in upright onto workboats 1a, 1b respectively, and the beam 6 made of steel is installed through ball joint mechanisms 5, thus constituting one catamaran type workboat. Base ships 1 are shifted to both sides of a caisson 2 temporarily positioned under a water surface, water is injected by a pump 3 and the base ships 1 are sunk, and ropes 7 are engaged with hangers 10 on the top face of the caisson 2. Water is drained by pumps 3 and the base ships 1 are floated, and the base ships are moved up to the erection location 13 of the caisson. Water is injected into the base ships 1 and the base ships are sunk, the bottom of the caisson is grounded, and the ropes 7 are removed and the base ships 1 are detached and shifted. Accordingly, the caisson can be installed accurately in shallow water.