SEAGATE Corporation, a “K” Line subsidiary, has launched the BISAN MARU, Japan’s first tugboat equipped with an onboard biofuel blender and an ultrasonic anti-fouling system. Built by Kanagawa Dockyard, the vessel features a CONHIRA blender that allows for custom fuel ratios up to 100% biofuel, ensuring operational flexibility even in ports with limited green bunkering infrastructure. Scheduled to enter service at the Port of Mizushima in August 2026, the tug serves as a high-tech testbed for “K” Line’s 2050 environmental vision of low-carbon maritime operations.
Kobe, Japan | April 22, 2026 – In a significant step toward the decarbonization of harbor operations, SEAGATE Corporation, a consolidated subsidiary of Kawasaki Kisen Kaisha, Ltd. (“K” LINE), celebrated the naming and launching of its newest tugboat, the BISAN MARU, on April 22, 2026.
Constructed by Kanagawa Dockyard Co., Ltd. in Kobe, the BISAN MARU represents a milestone in Japanese maritime engineering. While powered by a conventional diesel engine propulsion system, it is the first tugboat in Japan to integrate a dual-suite of green technologies: an onboard biofuel blender and an ultrasonic hull anti-fouling system.
Onboard Autonomy: The Conhira Biofuel Blender
Perhaps the most significant feature for the bunkering industry is the installation of a specialized biofuel blender manufactured by Conhira Co., Ltd. (Imabari City).
In an era where the availability of pre-blended biofuels (such as B20 or B30) can be inconsistent depending on the port, this system grants the BISAN MARU unprecedented operational flexibility. Key features include:
- Customizable Ratios: The system can blend marine fuel oil and biofuel at any ratio from 0% to 100%.
- Strategic Independence: It allows the vessel to produce its own blended fuel even in locations where bunkering infrastructure for biofuels is currently limited.
- CO2 Reduction: By optimizing the biofuel ratio based on availability and mission requirements, the vessel significantly lowers its carbon footprint compared to traditional tugs.
Combatting Biofouling via Ultrasound
To further enhance efficiency, the BISAN MARU serves as a real-world testbed for an ultrasonic hull anti-fouling system developed by M-SAT.LLC (Tokyo).
The system uses ultrasonic waves to prevent marine organisms from adhering to the hull. By keeping the hull clean, the vessel mitigates the increased drag associated with fouling, which traditionally leads to higher fuel consumption and emissions. Notably, this technology was originally developed for a hybrid EV tug slated for completion in 2027; its installation on the BISAN MARU provides a critical operational environment for final verification.
Vessel Specifications & Deployment
| Feature | Description |
| Vessel Name | BISAN MARU |
| Owner/Operator | SEAGATE CORPORATION (A “K” Line Group Company) |
| Shipbuilder | Kanagawa Dockyard Co., Ltd. |
| Primary Propulsion | Conventional Diesel Engine |
| Green Tech | Conhira Biofuel Blender & M-SAT Ultrasonic Anti-Fouling |
| Service Entry | August 2026 |
| Primary Port | Port of Mizushima, Okayama Prefecture |
The Broader Vision: Blue Seas for the Future
The launch of the BISAN MARU is a direct manifestation of the “K” LINE Environmental Vision 2050: Blue Seas for the Future. This long-term strategy, established in 2015 and revised in 2020, commits the group to a rigorous Greenhouse Gas (GHG) reduction action plan.
The “K” Line Group continues to explore a diverse portfolio of alternative energy solutions, including:
- Zero-Emission Fuels: Ammonia and Hydrogen.
- Carbon-Neutral Fuels: Bio-LNG and Synthetic fuels.
- Electrification: As seen in SEAGATE’s September 2025 agreement to construct a fully electric tugboat.
Following the ceremony, the BISAN MARU will undergo final interior outfitting before beginning its service at the Port of Mizushima this August. For the global bunkering community, the vessel serves as a proof-of-concept for how mid-sized harbor craft can bridge the gap between traditional fossil fuels and a decarbonized future through smart, onboard blending and maintenance technologies.
About Kawasaki Kisen Kaisha, Ltd. (K LINE)
Kawasaki Kisen Kaisha, Ltd. (“K” LINE) is a leading global provider of maritime transportation services, specializing in a wide range of vessels, including car carriers, bulk carriers, container ships, LNG carriers, and tankers. Founded in 1919, the company has built a reputation for excellence in shipping operations, with a strong focus on safety, environmental sustainability, and innovation.
As a pioneer in the maritime industry, K LINE has consistently embraced cutting-edge technologies and best practices to improve operational efficiency and reduce the environmental impact of its fleet. The company is committed to advancing the shipping industry’s transition toward a more sustainable future, with ongoing efforts to adopt low-impact fuels and technologies, such as LNG and ammonia, to reduce emissions and support decarbonization.
Source: Kawasaki Kisen Kaisha, Ltd.