Abstract: The requirements of the loading capacity of semi-submersible vessels are increasing with the diversified and large-scale marine equipment. The 4-island semi-submersible vessel has a fully-integrated main deck that is especially suitable for the transportation of the ultra large vessels and the marine structures. It introduces the structural design and strength evaluation of the conventional 3-island semi-submersible vessels, and discusses the deck load, allowable bending moment shear force and mid-ship section design that affect the cargo capacity of the semi-submersible vessel. These design points of the 3-island semi-submersible vessel are also applicable for the 4-island semi-submersible vessel. Compared to the conventional 3-island semi-submersible vessel, the 4-island semi-submersible vessel has the unique arrangement characteristics of the narrow and long side island that is overhanging the main hull. The structural design should consider comprehensively about the influence of the pipes and equipment for the ventilation and exhaust on the hull structure for the optimization design, and meet the requirement of heavy cargo transportation. It introduces the general idea of the structural evaluation of the 4-island semi-submersible vessel and the analysis of the relevant structural strength and the fatigue of key nodes. The vibration of the overall 4-island semi-submersible vessel and that of its side island are also evaluated to ensure the performance of the ship.

Key words: 4-island, semi-submersible vessel, structural design, mid-ship section design, design procedure, key technology, strength evaluation

摘要： 随着海工装备的多样化和大型化,对半潜船的装载能力要求越来越高。4岛式半潜船拥有贯通的主甲板,特别适合超尺度船舶和海工结构物的运输。文章简要介绍了常规3岛式半潜船结构设计和强度评估,对影响半潜船载货能力的甲板载荷、许用静水弯矩剪力和中剖面设计进行探讨,这些设计要点对于4岛式半潜船同样适用。与常规3岛式半潜船相比,4岛式半潜船具有边岛窄长、悬伸出船体的独特布置特点,结构设计时需统筹考虑通风排气等管路和设备对船体结构的影响优化设计,同时结构设计需满足重货运输。在此基础上介绍了对某4岛式半潜船进行结构评估的大致思路,分析相关结构强度和关键节点的疲劳设计,并对4岛式半潜船整体和边岛振动进行评估,保证船体性能。

关键词: 4岛式, 半潜船, 结构设计, 中剖面设计, 设计流程, 关键技术, 强度评估