The hybrid technology used to develop Foss Maritime’s Hybrid Tug is environmentally responsible—without sacrificing horsepower or maneuverability. With its efficient combination of batteries, generators and main engines, the Hybrid Tug is both powerful and green.

The world’s first hybrid tug, the Carolyn Dorothy, was built at Foss shipyard. An innovative approach to reducing air pollution, Foss’ Green Assist™ Hybrid Tug was designed to retain the power and maneuverability of her sister tugs, while dramatically reducing emissions and fuel consumption. The hybrid is quieter than its Dolphin sister tugs when operating on batteries that can be recharged using shore power. The hybrid design was awarded the EPA’s Clean Air Excellence Award for Clean Air Technology in 2008 (read more about our Environmental Awards and Recognition).

The Carolyn Dorothy has been in operation since 2009 and was joined in 2012 by a sister tug, the Campbell Foss. The Campbell Foss was converted from a conventionally powered tug to a hybrid at the Foss shipyard in Rainier.

The Benefits of Hybrid Technology

In the Ports of Los Angeles and Long Beach, over a seven-month period from January to July, 2010, the Center for Environmental Research and Technology (CERT) at the University of California, Riverside (UCR) found that hybrid technology:

  • Reduces emissions for all pollutants associated with diesel engines, without sacrificing power or maneuverability. The hybrid shows a significant reduction for pollutants related to combustion efficiency – 73% for particulate matter and 51% for nitrogen oxides. With reductions of 27% for fuel related pollutants (sulfur dioxide and carbon emissions).
  • Reduces fuel consumption by an estimated 20–30% by reducing idling and increasing engine efficiency.
  • Reduces main engine maintenance costs by reducing the number of operating hours by approximately 50% on the main engines.
  • Reduces noise pollution by using quieter batteries and generators instead of large diesel engines.
  • Improves safety by effectively removing any chance of power loss with multiple system redundancies and configurations.

Watch a video, produced by the Port of Long Beach, on the Hybrid Tug.