The Rules for the Classification of Trimarans by Lloyd's Register of Shipping are mainly for steel trimarans and are not applicable to aluminum-alloy trimarans. The fatigue life of a 120m aluminum-alloy trimaran is calculated by using the direct calculation method (spectral analysis method) based on the Miner linear cumulative damage theory. At the same time, the fatigue assessment results are corrected by the rain flow correction with consideration of the difference between treating the alternating stress process as a narrow band and the actual sea state. The results show that fatigue damage is easy to occur at the bridge of the aluminum-alloy trimaran, and hot spots have the different contributions to the fatigue damage under the different wave angle. The results of the fatigue life calculation are conservative if the alternating stress process is regarded as a narrow-band model. The conclusions can provide reference for the fatigue assessment of the aluminum-alloy trimaran.

In view of the oil and gas pollution caused by the ventilation of the fuel oil storage tank to the main deck, an optimal design scheme and a systematic design process have been proposed according to the characteristics of the closed overflow ventilation system of the fuel oil storage tank. It is proved that the optimal design scheme can meet the system design requirements and avoid the oil and gas pollution on the main deck through the combination of theoretical calculation and CFD simulation of a 2 200 TEU container ship.

The feasibility of offshore tandem lifting test for the semi-submersible lifting and disassembling unit has been discussed based on the procedure of the offshore tandem lifting with a 2 000 t crane, combining with the performance properties of the crane and the actual experiment environment. The operation of each segment in the procedure of the tandem lifting can be safe and reliable according to the characteristics of the unit. It can provide a theoretical basis for the later offshore tandem lifting test of the semi-submersible lifting and disassembling unit. The analysis results show that the tandem lifting procedures that meet the requirements of feasibility and safety can be tested at sea.

The demountable platform may have serious accidents during its operation, such as fire, instability, structure failure and load falling. It is necessary to arrange the evacuation and safe escape of platform personnel in time. A semi-submersible lifting demountable platform is examined to carry out the analysis of the possible serious accidents, the calculation of the escape time, the determination of the key points in the escape route, and the optimization of the escape route at the key points, as well as the analysis of the endurance time of the temporary refuge on the platform. The analysis results show that the personnel can evacuate in time with safeguards when an accident occurs on the platform.

This paper summarizes the basic principles of the general arrangement design for the dismantling platform. The arrangement of the lifting, power and accommodation, ballast and positioning systems are planned and designed around the lifting and accommodation functions of the platform. A design method for the key technology of the general arrangement of the semi-submersible crane dismantling platform has been presented to divide the general functional regions based on the implementation of the main functions of the platform. Under the requirements of the latest specification, the key systems of the platform is optimized and designed to provide experience and reference for the subsequent projects.