Arc Engineers Electric Conversion of Harbor Tug

Pacific Maritime Group's 50-foot Harbor Sentinel will swap its twin diesel engines for an Arc electric powertrain in a 12-month demonstration.

Updated on Nov. 5, 2026 in Electric Vehicles

Arc Engineers Electric Conversion of Harbor Tug

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Arc has begun engineering the battery-electric conversion of Harbor Sentinel, a 50-foot harbor tug owned and operated by Pacific Maritime Group. The project is funded by the Port of Long Beach and a Volkswagen Environmental Mitigation Trust grant administered by the Bay Area Air Quality Management District.

Why it matters

The conversion tests whether an electric powertrain can replace diesel propulsion on working harbor vessels, a step aimed at cutting emissions at Long Beach port operations. A successful demonstration could offer a practical, cost-effective alternative to building new vessels.

The tug's twin Cummins KT19 diesel engines produce 950 horsepower and carry 8,900 gallons of fuel, and the electric system targets a 2 MWh usable battery bank. Real-world performance and charging data will be gathered over the 12-month demonstration, which has not yet begun.

The players

Pacific Maritime Group

Pacific Maritime Group is a harbor tug operator that owns and runs the Harbor Sentinel and is hosting the electric conversion at its Long Beach terminal.

Arc

Arc is the electric powertrain company engineering the battery-electric conversion of the Harbor Sentinel and will collect the demonstration data.

Port of Long Beach

The Port of Long Beach is the public port authority funding the project through its Technology Advancement Program and SWIFT Program.

The details

PMG will remove both diesel engines and install an integrated electric powertrain tailored to the existing vessel, while PMG in-house will widen the Sentinel by 3.5 feet and build a new deck, midbody and pilothouse. Glosten is leading vessel engineering after completing a feasibility study and hull scan.

Harbor Sentinel joined Pacific Maritime Group's harbor fleet in 2023.
Arc began engineering the electric conversion in November 2026.
After commissioning, Harbor Sentinel returns to work from PMG's Long Beach terminal for a 12-month demonstration.

Roadmap

The project extends the Port of Long Beach's Clean Air Action Plan and its Technology Advancement Program into working harbor vessels. It applies electrification to a tug rather than shore equipment, a route that the port's emissions efforts have not yet tested at this scale.

Long Beach residents near the port may see reduced diesel exhaust from harbor operations if the demonstration succeeds. The project is a single-vessel test, so no change in daily driving or local service is expected from it directly.

The takeaway

Electrifying working harbor vessels is being tested here as a way to cut port emissions without building new ships. The 12-month results will show whether the approach is practical for broader adoption.