“Tsubasa” is used in towing operations which help large vessels get into and out of ports, mainly at the port of Yokohama and Kawasaki. She is equipped with a motor generator and high-performance rechargeable batteries in addition to conventional diesel engines.

The tugboat can operate on her diesel engines and/or on her electric-motors depending upon the operating power needed. The batteries can be charged not only by the onboard power generator, but also via electric-power from land.