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A solid oxide fuel cell (SOFC) and micro gas turbine (MGT) hybrid power system is a newly developed and promising power technology for ship power systems. Compared to conventional power plants on commercial ship, the technology can achieve a high efficiency (up to 80 %) and very low emission (up to zero) []. However, working as a marine power provider onboard ship, the control strategy of the hybrid system is one of the key challenges due to the requirement of balance between power generation from the SOFC's chemical reaction and the MGT's rotation mechanical power generation. In this paper, based on a system model, the control strategy for the hybrid power systems is presented. To get the maximum efficiency, the control of key parameters of the SOFC, such as stack temperature, fuel flow rate, fuel utilization and related power have been investigated and the control of power sharing between the two power sources of SOFC and MGT is proposed. The simulation results demonstrate that the control system can effectively control the SOFC and MGT subsystem and make them undertake their appropriate load separately with the forthcoming load. [ABSTRACT FROM AUTHOR]

series of carefully controlled experiments on the wave-generation characteristics of a model of a compartmented surface-effect ship has been conducted in a towing tank. Configurations of the model included cases encompassing one subcushion and two subcushions, as well as differing values of the pressures in the subcushions. It was shown that a reduced wave generation in the appropriate Froude number range could be achieved in this manner. Furthermore, a previously developed theory for the wave generation of marine vessels was verified for the model for a Froude number greater than 0.40. [ABSTRACT FROM AUTHOR]

Abstract  This paper covers an extension of the study of Doctors et al. (J Ship Res 52(4):263–273, 2008) on oscillations in wave resistance during the constant-velocity phase of a towing-tank resistance test on a ship model to the case of relatively shallow water. We demonstrate here that the unsteady effects are very prominent and that it is essentially impossible to achieve a steady-state resistance curve in a towing tank of typical proportions for a water-depth-to-model-length ratio of 0.25. This statement is particularly true in the speed region near a depth Froude number of unity. However, on the positive side, we show here that an application of unsteady linearized wave-resistance theory provides an excellent prediction of the measured total resistance, when one accounts for the form factor in the usual manner. Finally, a simple application of the results to the planning and analysis of towing-tank tests is presented. [ABSTRACT FROM AUTHOR]