Can AI cut Japan’s alarming collision rates?

With Japan recording almost 300 marine accidents each year, authorities are investing in AI collision prevention technology – and reminding mariners to use their ships’ whistles.

The Japanese government is stepping up efforts to reduce the large number of collisions now taking place in its increasingly congested seaways.

A typical, recently investigated incident took place in the early hours of 15 October 2019, after two ships turned onto the same course into Tokyo Bay’s busy Uraga Suido Traffic Route, 40 miles (64.3 km) south of the Japanese capital.

APL Pusan, a 25,000-ton container ship with a crew of 23 and a local pilot on board, was travelling at around 12 knots behind Shoutokumaru, a much smaller 390-ton coaster with just four crew on board, travelling at 10 knots.

Anticipating that APL Pusan could safely overtake Shoutokumaru, the pilot aboard APL Pusan informed the master that they should overtake on its starboard side. With no sign that the vessel ahead was intending to turn to starboard towards the upcoming Nakanose Traffic Route, the master agreed.

Believing that the manoeuvre would be straightforward, APL Pusan’s pilot decided there was no need to communicate with the vessel ahead to indicate his intention.

Unfortunately, the pilot wasn’t aware that the vessel ahead of him was actually called Shoutokumaru – so, when he overheard on VHF that Shoutokumaru intended to turn towards the Nakanose Traffic Route, he assumed it was a reference to another ship travelling 0.4nm off his port bow.

The APL Pusan

Whistle blast

As soon as the pilot realised that the ship he was overtaking was the one about to turn to starboard, he immediately called Shoutokumaru on VHF. Receiving no response, he ordered APL Pusan’s main engine to neutral, while the master ordered a hard turn to starboard and blew one long whistle blast.

As APL Pusan turned away, its port bow was in collision with Shoutokumaru’s starboard bow. APL Pusan’s starboard bow then collided with a channel buoy.

APL Pusan sustained dents and abrasions to its port bow shell plating and abrasions to its starboard bow shell plating. Shoutokumaru sustained damage to its bow bulwark and fractures to its foremast. The channel buoy received damage to its guard frame and other parts, including its sensor apparatus.

Weather conditions calm, visibility good

At the time of the incident the wind and sea were both calm and visibility was good. Both vessels had their navigation lights on, and there were no defects to their hulls, engines, or equipment. There were no casualties on either ship.

Report recommendations

A marine accident investigation report into the incident, published by the Japan Transport Safety Board (JTSB), makes the following recommendations:

• When masters or pilots intend to overtake another vessel in the same Traffic Route, they should identify the other vessel’s movements, confirm the other vessel's manoeuvring intentions at an early stage, and – if they cannot clarify the movements of the other vessel or maintain a safe distance – they should not overtake
• When pilots and bridge watch-keeping personnel are faced with a situation where there is a risk of another vessel approaching, they should keep in mind the possibility that the other vessel might not be aware of their own vessel – so they must announce their presence and manoeuvring intention on VHF, or with the ship’s whistle
• When navigating, bridge watch-keeping personnel should conduct an adequate and regular lookout across the vessel's bow side and stern
• Owners and managers need to support the master by establishing an environment in which the master can confidently go up to the bridge and command the vessel in narrow channels – and that the master should command the vessel in narrow channel navigation
• The master and bridge personnel need to share appropriate and necessary navigation information, such as navigation plans that include scheduled anchorages and ports of destination, on the bridge
• When conducting and intercepting VHF communications related to their own vessel, bridge watch-keeping personnel should continue to listen carefully until the communication is fully completed.

After the incident, the Tokyo Bay Pilot’s Association made the pilot on board APL Pusan at the time of the accident undertake a ship-manoeuvring training session on a simulator, under the exact conditions at the time of the accident.

Artificial Intelligence to the rescue

According to the JTSB, there were 2,863 marine collisions in Japanese waters between 2009 and 2019 – an average of more than 286 accidents per year.

To address the scale of these incidents, the Japan Coast Guard recently joined forces with technology giant Fujitsu to develop a new collision risk prediction system combining AI (artificial intelligence) and AIS (automatic identification system), designed to prevent collisions within the Tokyo Bay area.

In April, Fujitsu announced that a statistical analysis of initial trials found the new system helped Tokyo VTS reduce the time taken to assess and transmit risk warnings to vessels in danger of collision by an average of two minutes, regardless of the experience or skill of the operations controller on duty, and that the number of warnings issued to risk-prone vessels doubled.

Read the full Japan Transport Safety Board report.

Dennis O’Neill is a freelance journalist specialising in maritime.