TOKYO—Mitsui O.S.K. Lines, Ltd. (MOL; President & CEO: Takeshi Hashimoto) today announced that Propeller Boss Cap Fins (PBCF), sold by its group company MOL Techno-Trade, Ltd. (MOL Tech; President: Hirokazu Hatta; Headquarters: Chiyoda-ku, Tokyo), was certified as the “Best-selling Energy-Saving Ship Appendage Brand (Cumulative)”, by Guinness World Records(Note 1), and received the official certificate on December 23, 2021.

PBCF was co-developed by MOL, West Japan Fluid Engineering Laboratory Co., Ltd., and Nakashima Propeller Co., Ltd. (called Mikado Propeller Co., Ltd. at the time) in 1986, and went on sale by MOL in 1987. In 2000, sales operations were transferred to MOL Tech, which has been selling the PBCF.

It was the first device in the world to be commercialized to recover the energy wasted in the vortex that forms behind a rotating propeller and increase the thrust by breaking up this vortex. Analysis has shown that equipping a vessel with PBCF results in energy savings of 3% to 5%.

Since its introduction, as shipowners and operators in Japan and around the world have recognized the device’s performance, sales rose steadily. Orders reached 1,000 in 2006, 2,000 in 2011, and topped 3,000 in 2015. In 2017, based on the joint research results of MOL Tech, MOL and Akishima Laboratories (Mitsui Zosen) Inc., an upgraded PBCF, offering further improvements in energy-saving (Note 2), went on the market.

By 2021, PBCF cumulative sales exceeded 3,800 (the number of vessels equipped with PBCF exceeded 3600). Even now, about 35 years after its launch, PBCF is still selling exceptionally well as an energy-saving device for ships and has established itself as a bestseller.

PBCF installation improves fuel efficiency, which in turn reduces CO2 emissions from vessels, reducing the environmental impact of ocean shipping (Note 3). MOL Tech calculated that the expanded use of PBCF has contributed to a cumulative 46-million-ton reduction in CO2 emissions worldwide.

MOL Group continues to study hybrid combinations with other energy-saving devices such as stern fin, duct and rudder bulb and confirmed the synergistic effects in tests using a model. PBCF continues to evolve every day as MOL Group leverages this reliable technology, backed by about 35 years of refinement and accumulated expertise, to further improve propeller efficiency.

PBCF installed on a propeller

The MOL Group aims to achieve net zero emissions by 2050, as stated in “MOL Group Environmental Vision 2.1.” The group forges ahead with initiatives on “Enhancement of Energy-Saving Technologies” by leveraging Marine Knowledge and Technologies accumulated in its 130-plus years of history, including this PBCF project, and contributes to improvement of vessel fuel efficiency and reduction of environmental impact.

(Note 1) A GUINNESS WORLD RECORDS™ title for Best-selling Energy-Saving Ship Appendage Brand (Cumulative) is based on the cumulative 3,748 PBCFs sold (the sales record with 3,516 vessels including twin-screw vessels equipped with PBCF) as of the end of December 2020.

(Note 2) Please refer to May 19, 2017, press release:
MOL to Launch Sales of Redesigned, Refined PBCF – Meeting Higher Needs for Environmental Protection by Further Improving Energy-saving Performance –

(Note 3) Please refer to June 12, 2020, press release:

Propeller Boss Cap Fins (PBCF) Wins Environmental Technology Award from Japan Association for Logistics and Transport- 3% to 5% Energy Saving Reduces Merchant Ships’ Environmental Impact –

Presentation ceremony