General Design Study Of Deep-water Semi-submersible Crane/Pipelay Vessel’s Hull

With the development of offshore engineering, the semi-submersible crane/pipe-laying vessel(SSCV) has become increasingly important. Although it looks silly and big clumsy, its advantage has become more and more obvious in the sector of deepwater marine engineering, due to its huge lifting capacity, better stability performance and less sensitivity to environment.This thesis, based on theoretical calculation, model tests and other methods, carries out detailed study on the SSCV’s key performances, covering resistance performance, hull strength, lifting stability, dynamic positioning capability, hydrodynamic performance and so on, which are the key technologies for general design of this kind of ship hull.Studies are mainly focused on the shape, size, layout position and numbers of the columns planed for the vessel. These factors affect the performance of the SSCV and are the most important ones. This thesis proposes two candidate plans-- a ten columns plan and an eight columns plan. For the two plans, performances of hull structural strength, crane working stability, dynamic positioning capability, hydrodynamic responsibility and other aspects are systematically investigated and compared with each other correspondingly through both theoretical calculation and model tests and/or other methods. It gives out the pros and cons of the two plans in all respects, and helps us to decide the SSCV’s hull.Knowledges obtained in this thesis can be generally applied to the design of deep-water semi-submersible crane/pipe-lay vessel’s hull. They help us to estimate overall performance of the vessel and assist general design of the hull.