Rolls-Royce receives Approval in Principle for hybrid tug propulsion system

Classification organization ABS has granted Rolls-Royce an Approval in Principle (AIP) for its new hybrid propulsion system for tractor tugs. The AIP was granted following an evaluation of the world’s first hybrid tug, a vessel designed by Jensen Maritime and to be delivered by Nichols Brothers Boat Builders to Baydelta Maritime LLC in February 2019. The vessel will be the first tug boat installed with the Rolls-Royce hybrid propulsion system. ABS considers that the Rolls-Royce hybrid system is, in principle, compliant with ABS Rules for Building and Classing Steel Vessels Under 90m (2018); ABS Advisory on Hybrid Electric Power Systems (2017); and ABS Guidance Notes on Review and Approval of Novel Concepts. Griff Lane, SVP – commercial marine, Americas, Rolls-Royce, said, “Our long-standing partnership with Baydelta Maritime and close cooperation with Jensen Maritime, Nichols Brothers and ABS has paved the way for an innovative, environmentally friendly hybrid tug capable of safe and reliable operation and maximum bollard pull. The Rolls-Royce hybrid system enhances the tug’s escort capability, providing unsurpassed assist support to the ultra-large container ships that operate from US West Coast ports.” The Rolls-Royce hybrid propulsion system consists of power take-in (PTI), electric motors, shaft generators, a power management and control system, and main propulsion engines connected to US255 azimuth thrusters, allowing the vessel to operate in a diesel-mechanical, diesel-electric or boost mode configuration. This arrangement also optimizes omni-directional thrust and maneuverability, and provides improved crash stop capability. “The key benefit of a hybrid configuration is that it reduces the power requirement,” said Lane. “Typically, a tug the size of the Baydelta vessel would need a power output of 2,500kW. But the hybrid arrangement allows operators to achieve the required bollard pull from a smaller engine. It provides greater operational flexibility, which allows for the system to provide improved fuel efficiency, redundancy and reduced emissions.”