Some newbuild semisubmersible vessels have been equipped with a mooring system and thrust capability for station keeping.
Sue Wang American Bureau of Shipping
Some newbuild semisubmersible vessels have been equipped with a mooring system and thrust capability for station keeping. A comparative study on the performance of mooring systems with and without thruster assistance was performed using time-domain numerical simulations. Studies were done on a mooring system, a DP system, and a DP-assisted mooring system in 300 m (984 ft) and 1,000 m (3,280 ft) water depths. Both 12-line and eight-line systems were used.
The author examines those test results, which showed that the time-domain simulation shows transparency between mooring loads and thrust used; and that DP-assisted mooring design needs to include the mooring effect on the unit motion. The study also found that the addition of thrusters can reduce the required number of mooring lines from 12 to eight; and that any future analysis needs to include the interactions between thrusters, hull effect, current, and others to determine efficiency.
