FEBRUARY 7, 2018 — The latest multi-purpose tractor tug being built for Baydelta Maritime LLC by Nichols Brothers (see earlier story) marks a number of firsts in the application of hybrid technology in the tug market.
The 100′ x 40′ tug will be the seventh Nichols Brothers built tug in Baydelta’s fleet, but will be the shipyard’s first hybrid tractor tug. It is also the first hybrid tug designed by Jensen Maritime to enter the construction phase and the first application of Rolls-Royce hybrid technology in a tug.
The vessel is powered by two Caterpillar C3516 C Tier 3 diesel engines each rated at 1,995 kW @ 1,600 rpm supplied by Peterson Power of Portland, OR; and by two Rolls Royce supplied 424 kW electric motors.
The Z-drive system, two Rolls Royce 255FP units, can accept power from the diesel engines, electric motors and from both power sources. The electric motors are powered by three CAT C9.3, 300 kW each, 480V 3-phase @ 1,800 rpm generators, and one harbor generator. a C7.1 150 kW 480V, 3-phase @ 1,800 rpm also supplied by Peterson Power.
The Rolls Royce hybrid system allows for the vessel to operate direct-diesel, diesel-electric or fully-electric. This concept will save on fuel and reduce emissions, while suppling Baydelta with the same power and vessel characteristics needed for their operations. The flexibility provided by the drive system will allow loitering and transit at up to 7-8 knots in electric-only mode, then a bollard pull of >90 short tons in combined diesel-electric mode. The vessel will maintain the exceptional maneuverability, stability, and towing capacity of the earlier Delta Class vessels.
The tug will have seven berths and the major equipment on board includes; Rapp Marine electric hawser winch, and a single drum tow winch, and Centa carbon fiber shafts. In addition to the drive units and hybrid system, Rolls Royce will be supplying the control system and main switchboard, electric motors and their control cabinets.
Delivery of the vessel from the shipyard is scheduled for first quarter 2019.
“Nichols Brothers is excited about the opportunity to build our seventh Delta Class tractor tug for Baydelta Maritime” says Matt Nichols Executive Vice President, Nichols Brothers Boat Builders. “It is even more exciting to take the design even further with a hybrid concept. Between the expertise at Jensen, the fine craftsmen at Nichols, and the dedication of Baydelta, this vessel will demonstrate and exceed; durable performance, reliability, and environmental responsiveness.”
Rolls-Royce reports that will supply all electric motors, shaft generators and a power management and control system. The hybrid arrangement provides power to US255 azimuth thrusters with ducted fixed pitch propellers that can be rotated 360 degrees around the vertical axis. This arrangement optimizes omni-directional thrust and maneuverability as well as providing improved crash stop capability.
Erik Larsen, Rolls-Royce, Vice President – Tug and Fish, Americas, said: “Baydelta Maritime is a long-standing customer for Rolls-Royce, but 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. It shows this market, that the Rolls-Royce portfolio extends way beyond our US-type azimuth thrusters, the propulsion system of choice for this segment.”
Rolls-Royce and Baydelta have been working together since the 1990s, when the San Francisco -based operator specified its first azimuth thrusters. Since then Baydelta’s entire fleet of tractor tugs is equipped with these drive units.
“One of the reasons for success is the product’s ability to provide bollard pull of more than 90 tons,” said Larsen.
“The key benefit operating these thrusters in a hybrid configuration is that it reduced the power requirement. Typically, a tug of this size would need a power output 2500kW. The hybrid arrangement allows operators to achieve the required bollard pull from a smaller engine. It provides greater operational flexibility,” he added
Peter Zwart, VP of Operations, Baydelta Maritime, highlighted the maintenance benefits of the Rolls-Royce system. “We started building this current class of tugs in 2007 and now all our tugs have Rolls-Royce thrusters, the US 255. We know that with proper maintenance they last a long time, hopefully up to 15 years without a major overhaul”.
Commenting on their operational performance, Mark Barnum, Captain, Baydelta Maritime, added: “In San Francisco Bay containerships can enter at high rates of speed to maintain maneuverability and Rolls Royce thrusters are very responsive. We can go from full ahead to full astern in under 30 seconds. They also allow us to provide pilots with high tonnage breaks to prevent anything from happening during maneuvers.”