Patent ID: 6390008
Filing Date: 2002-05-21
Classification: B63B

Abstract:
A semisubmersible tender with a lightship displacement less than 15,000 short tons for a deep draft cassion vessel (SPAR) used as a production platform having a mooring system, comprising:a. a deck; b. a shape that results in a combined environmental load of less than 1000 kips within a 100-year extreme weather condition; c. a plurality of supports, each with a rounded shape, connected to said deck; d. a plurality of pontoons connected to said supports, each pontoon being capable of ballast transfer; e. at least two hawsers for connecting said tender to said SPAR, each hawser having a length which is selected from the group: the length of the tender, the tendering distance, the length of the SPAR, and combinations thereof; and wherein said hawsers have adequate elasticity to accommodate the wave frequency between the SPAR and the tender, and adequate stiffness to synchronize the mean and low frequency movements between the SPAR and the tender under an environmental load produced during a storm having a designation of up to a 10-year winter storm in the tendering position, and wherein said hawsers remain slack during a storm designed as at least a 10 year storm for the tender in the tender standby position; f. connecting means mounted on the tender securing a first end of each hawser; g. a hawser guidance system for each hawser to direct each said hawser to the SPAR; h. an at least 8 point mooring system for said tender; and i. means for creating global equilibrium between the SPAR's mooring system and said at least 8 point mooring system of said tender.