Reliability-Centered Development of Deep Water ROV ROSUB 6000

Abstract

AbstractThis paper presents the reliability-centered development of a deep water Remotely Operable Vehicle (ROV) ROSUB 6000 by the National Institute of Ocean Technology (NIOT), India. ROV operations are required during deep water interventions, such as well head operations, emergency response situations, bathymetric surveys, gas hydrate surveys, poly-metallic nodule exploration, and salvage operations. As per our requirements, the system needs to be capable of deep water operation for a period of 300 h/year and to be extremely reliable. Methodologies applied during the development and enhancement phases of electrical and control systems, taking into consideration the cost, space, and time constraints to attain the best possible reliability are detailed. Reliability, availability, and maintainability (RAM) studies are carried out to identify possible failure cases. It is found that ROV-Tether Management System (TMS) docking failure could be detrimental to the ROV system, and manipulator system failure could be detrimental to subsea operations. It has been calculated and found that the improved design has a mean time between failure (MTBF) of 4.9 and 6.2 years for ROV-TMS docking and manipulator system operations, respectively. The importance of monitoring tether cable healthiness during normal and winding operations and the systems implemented for effectively monitoring and maintaining the tether cable operational and functional healthiness, using the tether cable pay-out, vehicle heading, electric insulation, and optical performance sensors with the aid of a sea battery, are discussed. Maintenance decision support tables, which detail the operational personnel for the upkeep of the systems during the indicated interval so that the highest possible reliability is maintained during the mission period, are also presented.