**2.7. Operational endurance and available power system alternatives**

System endurance in unmanned underwater vehicle (UUV) operations consists of available total energy sources, vehicle system objectives, maneuvering path plan and design parameter characteristics. In general, the more the endurance is desired for UUV operations, the more the coordinated efforts are required during the vehicle design stage regarding the structural design, energy systems and power management. UUV endurance with respect to UUV system activities is characterized by range of missions, operation time and kinds of energy systems and is controlled by the capacity of on-board energy, hull structure of the vehicle, optimal propulsion and energy management system [23]. Until now days, these properties were investigated separately with system endurance as an individual component. In this study, we integrate all these components and make overall suggestions to the system endurance with respect to hull shape, power systems, propulsion efficiencies and respective activities of missions.
