部分船舶号灯配备及布置的改进和免除

对于部分船舶如近海供应船、拖船、救助船和半潜船等,鉴于其特殊结构布置导致号灯的配备及布置不能完全满足《1972年国际海上避碰规则》的要求,依据IMO通函的指导思想,对该类船舶号灯配备及布置存在的问题进行分析,提出相应的改进措施和免除办法。     

Research on the performance of passive heave compensator for tethered remotely operated vehicle system

A passive heave compensator is designed to enhance the operation safety of a 4.5 km remotely operated vehicle (ROV). This paper proposes a novel idea of designing a compensator with relatively low natural period to optimize gas volume and while adding a special device to remove the problem of ineffectiveness and resonance in long seas. Numerical simulations are done based on serious dynamic model of the whole system, including the compensator, the umbilical tether and the vehicle, solved by the fourth-order Runge-Kutta scheme. The compensator provides great attenuation of motion and tension in most sea states. As the working depth increases, the system natural period decreases, resulting in the occurrence of risk of resonance. By regulating the system damping, the compensator can be effective in these situations.