CONSTRUCTION ACTIVITY AT WORKBOAT YARDS EBDG designing fully electric truckable tug for Miller Marine

challenge, said Mike Complita, a principal with EBDG. “Although the hull itself is easily adapted to an all-electric option, the biggest challenge is to work with multiple smaller component providers who don’t offer a complete integrated solution, which means picking each component individually and ensuring everything communicates together properly and effectively,” he said.

One example is proprietary shore power plugs, which are being developed by several companies and must be treated differently than land-based applications.

The tug will be made up of two pieces — a shoe box-looking hull and a customizable superstructure with an enclosed steering station. Both pieces can be loaded separately on a single atbed trailer and towed anywhere in the U.S. without the need for any special permitting or road closures. Construction is scheduled to begin in the summer with the rst tug completed and put in operation by the rst quarter of 2024.

Elliott Bay Design Group, Seattle, and Miller Marine, Deltaville, Va., announced late last year that the two companies would design and build the rst fully electric truckable push tug.

The 26' tug is designed as a multifunctional utility boat that services marine construction sites, tends dredges and buoys, and can handle short range ferry operations and other near-shore operations such as crew transportation or line handling, EBDG said. The tug will be a test case to understand the market demand for an all-electric vessel, EBDG added.

Last year, Miller Marine reached out to EBDG to discuss partnering on development of a battery-electric option for Miller’s popular truckable tug design.

The shipyard saw a market opportunity for an electric version of a design they had been building for several years — a result of new Environmental Protection Agency regulations and government grants for zero- and low-emission vessel construction. Also, other states are starting to follow California’s lead in issuing credits to low-emission or zero-emission operations.

For EBDG, the new electric tug is another step in its goal to become a market leader in green and alternate fuel technologies, as well as an industry- rst test case to gauge market demand for an all-electric option. The electric tug will be built with a lot of room in the hull for batteries. EBDG will incorporate an electrical propulsion system into Miller Marine’s truckable tug design. Miller Marine will build the vessel at its 15,000-sq.-ft. production facility.

Designing electric or hybrid vessels is a bigger and more complex design

The 26' vessel will be powered by two permanent magnet (PM) motors with a total power of over 300 kW (400 hp). The new tug will not only be truckable, but 26' is also the cutoff for Subchapter M inspection by the Coast Guard.

Shore power will be used to recharge the vessel’s battery banks overnight, taking about eight hours. On a full charge, the vessel will operate for 12plus hours. A closed-loop uid cooling system will provide temperature control for the batteries, motors and electronics, maximizing their lifetime. The con guration is ideally suited for shallow and silty water operations, EBDG said. —

Eric van Rees

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