Rolls-Royce will supply the tug boat sector with its first hybrid propulsion arrangement, for installation to a multi-purpose tractor tug undergoing construction for Baydelta Maritime LLC. The vessel is being built at Nichols Brothers Boat Builders, in Washington State, USA.
The order represents the first hybrid tug using Rolls-Royce hybrid technology, the first installation of a hybrid system for Nichols Brothers and the first hybrid tug designed by Jensen Maritime, Crowley Maritime Corp’s Seattle-based naval architecture and engineering firm.
Rolls-Royce will supply two 424kW electric motors, shaft generators and a power management and control system. Peterson Power will supply two Caterpillar 3516C Tier 3 diesel engines, each rated at 1,995kW at 1,600rpm. The electric motors are powered by three Caterpillar C9.3 generators with 300kW each, which are 480V three-phase at 1,800rpm; and one harbour generator, a C7.1 150kW 480V, three-phase at 1,800rpm. All four generators will be supplied by Peterson Power.
The hybrid arrangement provides power to US255 azimuth thrusters with ducted fixed-pitch propellers that can be rotated 360o around the vertical axis. This arrangement, says Rolls-Royce, “optimises omni-directional thrust and manoeuvrability as well as providing improved crash stop capability”.
According to the OEM, the 100ft-long (30.5m) tug will feature the same ship assist and tanker escort capabilities as existing Delta Class harbour tugs but with “greatly improved” towing performance. The Rolls-Royce hybrid system enhances the vessel’s escort capability, enabling the tug to provide support to assist the ultra-large container ships that operate from US West Coast ports.
Erik Larsen, VP - Tug and Fish, Americas, Rolls-Royce, said, “This order is of particular significance because it marks our first Rolls-Royce hybrid system for a tug. The tug will provide improved fuel efficiency and emissions. Typically, a tug of this size 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.”
The new tug Jensen Maritime has designed for Baydelta is planned for delivery in February 2019. It will be capable of a 90 short-ton bollard pull and carrying up to 71,000 gallons of fuel and 4,300 gallons of fresh water. A large pilot house will provide all-around visibility, and the deckhouse will have a large mess and lounge area along with accommodation for an eight-person crew.