Autonomous Ships and the MASS Code
An autonomous ship can carry out some or all of its navigation and operating decisions without human intervention.
An autonomous ship can carry out some or all of its navigation and operating decisions without human intervention. The IMO adopted the first global rules for these ships, the MASS Code, in May 2026. The code has applied on a voluntary basis since 1 July 2026, and a mandatory version is expected to enter into force on 1 January 2032.[2] In Japan four ships entered commercial service in 2026 with autonomous navigation certificates. There is still no regular ocean-going merchant ship running with no crew at all.
Tesla's Boat
The idea is far older than commercial use. At the first Electrical Exhibition at Madison Square Garden in New York in 1898, Nikola Tesla put a small boat in an indoor pool. With a control box he worked its rudder, propeller and lights by radio. There was nobody on board and no cable. He had filed his patent on 1 July and received number 613,809 on 8 November that year. A year later he showed an improved, submersible version at a conference in Chicago.[1]
Bridge Control and Smaller Crews
On merchant ships automation started in the engine room. The cargo ship Kinkasan Maru, built in 1961 at Mitsui's Tamano yard for Mitsui O.S.K. Lines, could have its main engine run directly from the bridge, and engineers watched the machinery from a central control room. Japan's society of naval architects calls it the world's first automated ship.[10] As automation spread, crews shrank. An ocean-going cargo ship that needed over a hundred men in the 1900s could manage with as few as 15 by 1998.[11]
In the 2010s, with better sensors and artificial intelligence, the work reached the bridge. The arguments had not changed. Crew makes up 20% to 30% of the total cost of a cargo voyage, and a 2018 Allianz study attributed 75% to 96% of marine accidents to human error.[12] In 2016 Oskar Levander of Rolls-Royce was saying the question was when, and no longer if.[12]
Falco and the Turku Centre
The first concrete demonstration took place on a Finnish ferry. On 3 December 2018 the Finferries car ferry Falco sailed by itself from Parainen to Nauvo with Rolls-Royce systems and 80 guests on board. The return leg was run remotely from an operations room in the centre of Turku, about 50 kilometres away. The system combined sensor data with artificial intelligence to recognise objects and make collision avoidance manoeuvres.[3] The route was short, the water was familiar and a captain stood by.
Yara Birkeland's Short Route
On the cargo side the ship most often cited is Norway's Yara Birkeland. The fertiliser company Yara moved its products by truck from its Porsgrunn plant to the port at Brevik. In 2017 it planned an electric, autonomous container ship with Kongsberg, aiming to remove 40,000 truck trips a year. The Norwegian government paid about a third of the cost.[13]
The 120 TEU ship runs about 7 nautical miles between those two points. It was christened at Brevik on 29 April 2022 and began work with a crew, because rules required a crew on board for two years before remote control could be considered.[13] Yara reports that the first fully autonomous voyage took place in March 2023 under human supervision. The trial schedule ran to the end of 2024. Mooring was still done by hand, with robot arms under test.[4] On this ship mooring turned out harder than navigation.
Sea Hunter and Mayflower
The military moved faster. The 40-metre trimaran Sea Hunter, christened at Portland on 7 April 2016, was built for a DARPA submarine-tracking programme with no living quarters at all. The programme passed to the Office of Naval Research in 2018.[5]
The most visible civilian trial took place on the open ocean. ProMare and IBM's 15-metre aluminium Mayflower left Plymouth in June 2021 and returned three days later with a mechanical fault. It set off again on 27 April 2022. After repairs in the Azores, a generator starter circuit failed at the end of May, so it turned from Virginia to Halifax and arrived in early June. The last stretch was under tow. The boat runs on solar panels and a backup diesel generator, reaches up to 10 knots and cost US$1.3 million to build.[6][7] It crossed the Atlantic with nobody on board, but what broke was a starter circuit and no piece of software. That raises the question of who repairs the machinery in mid-ocean.
Prism Courage and Japan
A larger trial was running at the same time. SK Shipping's LNG carrier Prism Courage left Freeport, Texas, on 1 May 2022 and reached South Korea on 2 June. A system from HD Hyundai's Avikus handled navigation for roughly half of the 20,000-kilometre voyage and changed course in encounters with more than 100 ships. The captain and officers were on board, and they took over near ports and in the Panama Canal.[7]
The longest-running programme came from Japan, partly because of a shortage of coastal seafarers. The Nippon Foundation launched MEGURI2040 in February 2020, aiming for autonomous navigation on half the coastal fleet by 2040. In the first stage five groups ran trials with six ships between January and March 2022. The car and passenger ferry Soleil completed a 240-kilometre run between Shinmoji and Iyonada on 17 January 2022.[8][9][14]
In the second stage the work moved into commercial service. ClassNK classed four ships between late 2025 and early 2026, and Japan's transport ministry approved their systems. The 134.9-metre newbuild container ship Genbu works between Kobe, Osaka, Nagoya, Yokohama and Tokyo. The 173.8-metre ro-ro Hokuren Maru No. 2 runs between foggy Kushiro and Hitachi. The ferry Olympia Dream Seto and the small container ship Mikage went through the same process. Two operation centres on land support the ships.[14][15] The published documents do not say how many people remain on board. The foundation's "Level 4" means navigation without human intervention in a designated area under certain conditions.[15]
The IMO Rulemaking
As trials multiplied the legal question grew, because maritime rules assume a master and crew on board. The IMO Maritime Safety Committee decided in June 2017 to review the existing conventions, and the exercise ended in May 2021.[16] It divided autonomy into four degrees. In degree one seafarers are on board and some processes are automated. In degree two the ship is run remotely with seafarers on board ready to take over. In degree three it is run remotely with none on board. In degree four its own system makes the decisions. The degrees are not a ranking, and a ship may use more than one on a voyage.[16]
The review found gaps across many conventions. Its priority issues were what master, crew and responsible person mean, the remote control centre, and whether a remote operator counts as a seafarer. The collision regulations and the STCW training convention were among the priority instruments. The committee recommended one goal-based MASS instrument over changing each convention separately.[16]
The MASS Code and Where It Stands
That instrument was adopted on 22 May 2026 at the committee's 111th session. The International Code of Safety for Maritime Autonomous Surface Ships is voluntary for now and has applied since 1 July 2026. It covers cargo ships under SOLAS, with passenger ships outside its scope. A single autonomous or remote function can bring a ship within it, even with crew on board.[2][17] The code is goal-based and prescribes no specific technology. It has three parts: principles, certification and training, and functional goals. Approval requires a risk assessment, and the remote operations centre is certified as well.[17][18]
On the most contested point the code gave a clear answer. A ship will always have a human master. The master may be off the ship but must be able to intervene and carries overall responsibility.[2][17] Who is liable after an accident is outside the code. The law firm Hill Dickinson notes that existing liability conventions still assume a master and crew on board, that the code does not allocate liability, and that questions reaching operators and software developers are left to contracts and national law. Search and rescue is an open technical issue too, since an uncrewed ship may have to pick people out of the water.[18]
The timetable is set. MSC 112 in December 2026 will draft the framework for an experience-building phase, in which member states try the voluntary code and collect data. Drafting of the mandatory code begins in 2028, with adoption expected by 1 July 2030 and entry into force on 1 January 2032.[2] DNV notes that the committee may revisit this timeline and that completing the experience phase is no precondition for the mandatory code.[17]
Signals and Cyber Security
A remotely run ship is only as safe as its satellite link and position signal. The 2026 Iran war made that risk concrete. In March 2026 the Joint Maritime Information Center reported more than 600 satellite positioning disruptions around Hormuz within 24 hours, and tracking systems showed tracks of phantom vessels.[19] An officer on the bridge can catch this by eye and radar. On an uncrewed ship software has to make the same correction, and if the link drops the ship has to fall back on safe behaviour. Hill Dickinson writes that cyber resilience is now treated as a core safety issue.[18]
Mooring, Hoses and Signatures
Autonomy runs into trouble with the work done at the ship's side. Mooring was still unsolved on Yara Birkeland. A bunker delivery also needs someone to connect the hose and sound the tank. The MARPOL Annex VI sample is sealed and signed by the supplier's representative and the master or the officer in charge of the bunker operation, then kept on board for at least 12 months. The delivery note stays on board for three years.[20] Whatever the type of fuel, somebody responsible has to do this. On the electric Yara Birkeland the same question becomes shore charging, while on a large ship it is still waiting for an answer. The MASS Code sets no date for seafarers to leave the ship.
Frequently asked questions
What is an autonomous ship?
An autonomous ship can carry out some or all of its navigation and operating decisions without human intervention.
What is the MASS Code and is it in force?
The MASS Code is the IMO safety code for autonomous ships, adopted on 22 May 2026. It has applied on a voluntary basis since 1 July 2026. A mandatory version is expected to be adopted by 2030 and enter into force on 1 January 2032.
Will an autonomous ship have a master?
Yes. The MASS Code requires a human master at all times. The master may be off the ship but must be able to intervene and carries overall responsibility.
Are there autonomous ships in commercial service?
In Japan four ships under MEGURI2040 entered commercial service in 2026 with autonomous navigation certificates, on set coastal routes. There is still no regular ocean-going merchant ship running with no crew at all.
Sources
- Nikola Tesla Museum. Tesla's Remotely Controlled Boat.
- IMO. IMO Adopts First Global Code for Autonomous Ships, May 2026.
- Rolls-Royce. Rolls-Royce and Finferries Demonstrate World's First Fully Autonomous Ferry, 3 December 2018.
- Yara. Yara Birkeland, Two Years On.
- Wikipedia. Sea Hunter.
- Wikipedia. Mayflower Autonomous Ship.
- Voice of America. Two Self-Sailing Ships Cross World Oceans for First Time, 2022.
- Nippon Foundation. MEGURI2040 Demonstration, 11 January 2022.
- Mitsubishi Heavy Industries. Successful Demonstration Test of World's First Fully Autonomous Ship Navigation Systems on Coastal Ferry, 17 January 2022.
- Marine Link. Report on the heritage certificate for Kinkasan Maru.
- Lloyd's Register Foundation Heritage Centre. Mina Ghosh, Literature Review: Autonomous Ships.
- Wikipedia. Autonomous cargo ship.
- Wikipedia. MV Yara Birkeland.
- The Nippon Foundation. MEGURI2040 update, 24 August 2026.
- Nippon Foundation. Announcement on the inspection of four ships, 27 March 2026.
- IMO. MSC.1/Circ.1638, Outcome of the Regulatory Scoping Exercise for the Use of Maritime Autonomous Surface Ships, 3 June 2021.
- DNV. IMO MSC 111: New MASS Code Adopted, 2026.
- Hill Dickinson. IMO Adopts International Safety Code for Autonomous Shipping, 2026.
- gCaptain. Electronic Fog of War: GPS Spoofing Distorts Ship Traffic Near Hormuz, 10 March 2026.
- Barbados Maritime Ship Registry. Bulletin 345, Port State Control, MARPOL Annex VI, Fuel Oil Sampling, 16 June 2021.
