VESSEL REVIEW | eWolf – First US-built all-electric tug joins Crowley’s ship assist fleet

US shipping company Crowley Maritime Corporation will soon place a new all-electric ship assist tug into service at the Port of San Diego.

Named eWolf, the tug was designed by Seattle-based Crowley Engineering Services and built at the Coden, Alabama facilities of Master Boat Builders. Crowley claims that it is the first all-electric tug to be built in the United States, and that it will operate with zero emissions while providing the complete performance capabilities of a traditional tug. Specifically, the tug will help generate reductions of 178 tons (161 tonnes) of NOx, 2.5 tons (2.26 tonnes) of diesel particulate matter, and 3,400 tons (3,084 tonnes) of CO2 over the first 10 years of its operations, thanks to the installation of an integrated electrical propulsion system supplied by ABB.

The tug has an LOA of 82 feet (25 metres), a beam of 39.3 feet (12 metres), and a draught of 9.8 feet (three metres). The ABB propulsion system, which also includes a Corvus Energy 6.2MWh energy storage system, drives two Schottel SRP 430 LE 2,050kW rudder propellers to deliver a bollard pull of 70 tons (63.5 tonnes). Two small generators are also fitted to be used in emergencies and to allow sailing at reduced speed over greater distances.

The electric propulsion on eWolf also guarantees significantly reduced noise. This allows the tug to continue to operate even during nighttime without disturbing residents in the communities that are situated close to the port, which sees significant vessel traffic nearly similar to that of the larger California ports of Los Angeles and Long Beach.

Another notable feature of the electric propulsion is the lack of an exhaust system. Because there are no protruding exhaust pipes, the wheelhouse crew will benefit from a full 360 degrees of visibility, thus significantly improving situational awareness when manoeuvring through busy port waters.

The energy storage system has shore charging capability, though the tug was designed to be able to operate a full day without having to charge after every task. ABB's proprietary DC distribution system will allow for more efficient shore charging, minimising the need for the tug to berth during periods of sustained operations.

ABB said the tug will also be ready for remote control operations. The company's remote control and autonomous navigation systems are designed for future integration along with AI technology to help increase safety and efficiency.

Crowley designed eWolf in compliance to both American Bureau of Shipping class rules and US Coast Guard Subchapter M regulations. The tug is scheduled to commence operational sailings at the Port of San Diego in the spring of 2024, replacing an existing diesel-powered tug in the Crowley fleet.