Nichols Brothers Boat Builders (NBBB) has successfully trialed and delivered Baydelta Maritime’s new Delta class hybrid tractor tug. The vessel, called Delta Teresa, is the seventh tractor tug NBBB has built for Baydelta and its affiliated companies, but the first hybrid.
Shawn Bennett, CEO, Baydelta, said, “The Delta Teresa is a great addition to our fleet of 90-ton tugs. Baydelta and Nichols Brothers have a long-standing relationship, together creating what is widely recognized as the premier harbor tug class.”
The tug is powered by two Caterpillar C3516 C Tier 3 diesel engines each rated at 1,995kW at 1,600rpm and by two 424kW electric motors. The Z-drive system, comprising two Kongsberg 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 300kW, 480V three-phase at 1,800rpm generators, and one harbor generator – a C7.1 150kW 480V, three-phase at 1,800rpm.
The hybrid system allows the vessel to operate in different power modes: direct-diesel, diesel-electric or fully electric. According to NBBB, during trials the tug’s performance met or exceeded all expectations. Free running speeds, under full power, of higher than 14kts (16mph / 26km/h) were obtained along with almost 10kts (11.5mph / 18.5km/h) on electric motor power only.
Designed by Seattle-based Jensen Maritime Consultants, the tug carries an ABS Loadline certificate and complies with United States Coast Guard requirements. It has seven berths and the major equipment on board includes a Rapp Marine electric hawser winch and a single drum tow winch; the drivetrain is connected with Centa carbon-fiber shafts. In addition to the drive units and hybrid system, Kongsberg supplied the control system and main switchboard, electric motors and their control cabinets.