A partnership of Japanese companies formed by Mitsui E&S Shipbuilding (MES-S), Mitsui OSK Lines (MOL), the Tokyo University of Marine Science and Technology (TUMST), Akishima Laboratories (Mitsui Zosen), and MOL Ferry Company have successfully completed a demonstration test of a jointly developed auto berthing and un-berthing system at an actual pier in Oarai Port, Ibaraki Prefecture, using the large-size car ferry Sunflower Shiretoko, owned by MOL Ferry.
Japan's Ministry of Land, Infrastructure, Transportation and Tourism (MLIT) had selected this joint initiative for its autonomous vessel demonstration project.
Studies by the project partners have revealed that human error accounts for around 80 per cent of maritime accidents. Since the partners believe that automated and autonomous operations of vessels can significantly reduce the occurrences of human error, such technologies must have the potential to be developed further.
Autonomous operations have also garnered praise for its role in reducing the workloads of vessel crews, which the partners claim will signify a fundamental change in the conduct of marine transport.
Through this project, the MLIT aims to make practical use of autonomous vessels more widespread by 2025.
The project partners chose berthing and un-berthing operations as their area of focus due to their being among the most challenging phases of overall vessel operation and therefore a phase wherein accidents caused by human error sometimes occur.
The demonstration project was initiated to help identify technical issues by trialling autonomous operation with an actual vessel and studying ways to make the technology more suited to practical, real-world application.
The initial trials were carried out from late 2018 to early 2019 using the TUMST training vessel Shioji Maru. The partners conducted 54 tests wherein the vessel was automatically berthed to a "virtual pier" in the open water. The technology had proven effective, and the information gained from the tests was used to guide the partners in further developing manoeuvring controls, defining criteria for deciding whether to cease or continue autonomous operation, and considering the appropriate degrees of speed, course, and distance with the aim of ensuring an adequate safety margin.
Even with this initial success, the project partners had also wanted to test the technology on a much larger vessel, preferably one being operated on domestic passenger services, to validate the effectiveness of the system when it is subjected to heavy, day-to-day use.
The partners said the demonstration test involving Sunflower Shiretoko is unique for two reasons, namely, 1) the use of a large car ferry (11,410 GT) without disrupting its regular scheduled service and 2) execution of the test using an actual pier.
The project team developed a ship operation plan, an operation guide, criteria for canceling the test, and various other parameters. They also used simulations to conduct a thorough safety assessment under various conditions. In addition, the team conducted the actual demonstration test during March and April 2021 and verified safety of the vessel by autonomously berthing and un-berthing at a virtual pier projected on the water, similar to the earlier trials using Shioji Maru.
After collating the results of this demonstration test, the project team will conduct demonstration tests of auto berthing and un-berthing at actual berths with other ship types with the aim of developing a highly versatile technology that can be applied throughout the wider maritime industry.