HYBRID SHIP ASSIST ETUG+

Based on what the company has learned in its construction and design of the eWolf tug, Crowley Engineering Services recently developed a first-in-class battery hybrid ship assist/escort tug (eTug+) for harbor and near shore applications. Utilizing electrically driven L-drives, the combination of diesel generators and a battery energy storage system offer multiple scenarios to provide economical and environmentally friendly operations, whether it be tied up at the dock, underway to assist, or conducting high speed escort operations.

Coulston Van Gundy, vice president of construction and engineering for Crowley, told Marine Log that the vessel is targeted to be launched in 2025.

Designed with the help of current tug operators, visibility is maximized by having large windows in the pilothouse and a raised operator platform. The bridge is equipped with suitable monitoring and control equipment for intelligent maneuvering, remote operations, and future semi- and full autonomous operations.

Power is primarily provided by two lithium-ion battery energy storage systems (BESS). Four diesel generators provide back-up power as well as charging power to the BESS. High power direct current (DC) and low power alternating current shore connections are installed on the vessel to allow charging of the BESS from shore.

Minimum Bollard Pull is expected to be 90 short tons ahead and astern via two (2) azimuth stern drives (ASD). A Class II+, electrically driven hawser winch with slipping disc brakes forward and an anchor capstan windlass aft provide line handling capability for escort and ship assist work. Both the hawser winch and ASDs will have regenerative capability.

The vessel is designed for offshore work as well as harbor operations. Individual staterooms are provided for a compliment of five persons with a maximum crew complement of six persons. The lower accommodations are forward, with the battery rooms and electronics room/machinery space located aft. Generators are located on the main deck to allow for ease of maintenance while deploying noise and vibration reduction strategies and technologies for maximum crew comfort.

In January, Crowley Engineering Services achieved Platinum ISO 9001 certification. Van Gundy says this certification means, “our entire management system has achieved a high level of performance that benefits our customers, whether its traditional maritime, offshore wind or other marine engineering and construction management. It’s important to note this isn’t a single product but applies to an organization.”

The eTug+ has been designed for harbor and near shore applications.