What is a maritime autonomous surface ship (MASS)?

Unmanned surface vessel use cases

Maritime autonomous surface ships are autonomous surface vessels which operate in open oceans with an onboard crew. Maritime autonomous surface ships can be used for a range of monitoring purposes, and are particularly valuable for their high endurance and cost efficiency. Whether for the purposes of oceanography, national security, marine life and marine protected areas, or to increase surveillance of offshore infrastructure, maritime autonomous surface ships are an increasingly popular solution.

Maritime autonomous surface ships or MASS includes every description of vessel or craft used in navigation that can for any part of its voyage, fully or in part navigate or operate autonomously or through remote operations.

What is the regulatory definition of Maritime Autonomous Surface Ships?

For the purpose of the IMO’s regulatory scoping exercise, “Maritime Autonomous Surface Ship (MASS)” is defined as a ship which, to a varying degree, can operate independently of human interaction.

To facilitate the progress of the regulatory scoping exercise, the degrees of autonomy are organized (non-hierarchically) as follows: 

  • A ship with automated processes and decision making, where a crew are on board to operate and control systems and functions but some operations may be automated.

  • Remotely controlled ships with seafarers on board, where the ship is controlled and operated from another location, but there are still seafarers are on board.

  • Remotely controlled ship without seafarers on board, an “uncrewed surface vessel,” where the ship is controlled and operated from another remote location. 

  • Fully autonomous ship or unmanned surface vessel, where the operating system of the ship is able to make decisions and determine actions by itself.


Maritime autonomous surface ships working in swarms

MASS ships can be made to operate as a swarm in order to increase reliability and the scope of data. In a sensor network, each individual vessel behaves as an intersection or ‘node’, able to communicate with other vessels in the swarm, thus providing highly reliable data from a range of locations. In the absence of an onboard crew, the vessel is operated by humans either from another, manned vessel, or from land, essentially allowing more time to be spent tracking and intellectualising data trends, instead of manpower and energy being spent solely on data collection. Operating as a swarm, maritime autonomous surface ships provide improved geographical coverage and data collection, acting as both a deterrent to those committing illegal activities, as well as providing a means of intercepting vessels and recording high resolution footage for prosecution.


Zero emission maritime autonomous surface ship

Due to their increasingly popular use as climate monitoring vessels, there is a need for maritime autonomous surface ships to avoid producing waste of emissions. ACUA Ocean, a British maritime cleantech startup, is developing the world’s first long endurance maritime autonomous surface ships powered by liquid hydrogen (H-USV). Their MASS will release no carbon emissions and will become the first purpose-built maritime autonomous surface ship to operate using only hydrogen fuel. By utilising the latest in AI and computer vision technology to detect threats and anomalies such as objects in the water, oil spills and incursions, ACUA’s H-USVs will be instrumental in monitoring British seas. These maritime autonomous surface ships will have a long endurance of 70+ days at 5 knts, with reduced maintenance requirements, meaning increased operational time on site. They are, therefore, a more humane, more cost-efficient solution to the need for increased maritime monitoring and surveillance.