MARINE SEMI-SUBMERSIBLE PLATFORM OF HIGH WAVE RESISTANCE Russian patent published in 2002 - IPC

FIELD: shipbuilding; semi-submersible platforms. SUBSTANCE: proposed marine semi-submersible platform includes upper working structure on which main equipment is arranged depending on purpose of platform (for example, drilling equipment; two rows of columns at section S_c and height H_c, which carry upper working structure ; two pontoons having volume V_p and height H_p, which give support for columns; these pontoons are also used for mounting the power plant, fuel tanks and ballast tanks; horizontal strips of wing profile found between pontoons perform function of strength members and other special functions. When ballast tanks are blown-off, platform is in surface cruise position at draft T_w and preset transverse metacentric height and reserve of buoyancy. When ballast tanks are filled, platform lowers to semi-submersible position at draft T_er, and preset transverse metacentric height and reserve of buoyancy. Proposed invention includes mathematical relationships for determination of total height and cross-section area of columns, distance between columns along pontoons, volume and height of pontoons and distances between them, volume of ballast tanks and permissible height of center of mass of platform according to preset payload, rated height and length of waves, preset reserve of buoyancy in cruise position, as well as metacentric heights for cruise and working position. EFFECT: minimization of wave disturbance forces acting on platform in design range of swell and motions, as well as its displacement at simultaneous satisfying of requirement imposed on reserve of buoyancy, stability and seaworthiness. 3 cl, 2 dwg