Mitsui Engineering and Shipbuilding Company Limited

Hitoshi Narita

Masanao Oshima

Nobuyoshi Yashima

Hiroshi Tabuchi

Yoshikuni Kunitake

Hikaru Yagi

A floating offshore structure which is moored at a fixed position on the sea by means of mooring hawsers and anchors connected to the ends thereof respectively for conducting a submarine excavating operation from a deck of the structure. The structure includes a moorage hull part provided with a vertical through-hole formed therein for receiving an excavating drill pipe and the mooring hawsers and a movable hull part connected to the moorage hull part so as to be rotatable within a horizontal plane. The movable hull part is constituted as a hull defining the outer wall of the floating offshore structure and connected with the moorage hull part by inserting it into a moorage hull part receiving hole formed at a position closer to the bow thereof. The movable hull part has near its water plane a horizontal section with a substantially oval shape formed by a fore draft part in a substantially circular or polygonal shape with the moorage hull part receiving hole as a center and an after draft part taperingly projecting aft from the fore draft part.

Floating offshore structure

A floating offshore structure which is moored at a fixed position on the sea by means of mooring hawsers and anchors connected to the ends thereof respectively for conducting a submarine excavating operation from a deck of the structure. The structure includes a moorage hull part provided with a vertical through-hole formed therein for receiving an excavating drill pipe and the mooring hawsers and a movable hull part connected to the moorage hull part so as to be rotatable within a horizontal plane. The movable hull part is constituted as a hull defining the outer wall of the floating offshore structure and connected with the moorage hull part by inserting it into a moorage hull part receiving hole formed at a position closer to the bow thereof. The movable hull part has near its water plane a horizontal section with a substantially oval shape formed by a fore draft part in a substantially circular or polygonal shape, with the moorage hull part receiving hole as a center and an after draft part taperingly projecting aft from the fore draft part.

The present invention relates to a ship with structural improvements which prevent factors causing an increase in the horsepower required for propulsion or an increase in propeller cavitation, hull vibration and noise, all of which result from the water turbulence and nonuniformity of flow field along the stern caused by corpulence of ship, and the present invention provides such a ship with a structural improvement comprising having a ring-shaped construction directly attached to the hull on each of the ship's stern and in front of the propeller.

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Musashino, Japan

Hitoshi Narita