Mass Code

International Maritime Organization's MASS Code, formally adopted through Resolution MSC.595(111) in May 2026. The Maritime Autonomous Surface Ship, or MASS, Code establishes the world's first comprehensive international framework for autonomous and remotely operated ships. It applies primarily to cargo ships above 500 gross tonnage engaged on international voyages and aims to ensure that autonomous vessels achieve a level of safety and environmental protection equivalent to conventional ships. Although currently non-mandatory, the Code represents a significant milestone in maritime digitalization and is expected to become mandatory by 2032. A Maritime Autonomous Surface Ship is a vessel capable of operating with varying degrees of independence from direct human interaction. The Code identifies four levels of autonomy, ranging from automated ships with crew onboard to fully autonomous vessels making decisions without human intervention. A key principle is that enhanced automation alone does not make a ship a MASS. The vessel must undergo approval, certification, and safety assessment processes. The IMO emphasizes a functional approach, allowing conventional, remotely controlled, and autonomous functions to coexist while maintaining safe operations. The MASS Code follows a goal-based regulatory framework. Instead of prescribing specific technologies, it establishes safety goals, functional requirements, and expected performance standards. Part I covers introduction, application, definitions, and code structure. Part II establishes principles relating to surveys, approval processes, risk assessment, operational context, system design, software, security, and maintenance. Part III addresses technical requirements for navigation, connectivity, remote operations, fire protection, machinery, cargo handling, and structural integrity. This flexible approach encourages innovation while maintaining regulatory consistency. The development of the MASS Code reflects nearly a decade of international collaboration. Work commenced in 2017 when the IMO Maritime Safety Committee began examining autonomous shipping. Interim guidelines were issued in 2019, followed by a Regulatory Scoping Exercise in 2021 to identify gaps in existing conventions. Between 2022 and 2024, multiple IMO committees collaborated to address legal, operational, and environmental issues. The non-mandatory Code was adopted in May 2026 and entered into effect on 1 July 2026. Experience gained during the coming years will support the development of the mandatory Code planned for implementation in 2032. The approval process for a MASS follows a structured eight-step pathway. It begins with concept definition, where shipowners and designers identify the autonomous functions. This is followed by the development of the Concept of Operations, or CONOPS, and the Operational Design Domain, known as ODD. A comprehensive risk assessment is then conducted. Designers must demonstrate that the vessel meets safety and performance objectives equivalent to conventional ships. Following evaluation by the Flag Administration, surveys are conducted and certificates issued, confirming compliance with the MASS Code. Risk assessment forms the foundation of the MASS approval process. Based on ISO 31000 principles, it begins with hazard identification covering technical, human, environmental, and operational risks. The risks are analyzed by evaluating both likelihood and consequences before determining their acceptability. Appropriate control measures such as prevention, mitigation, redundancy, and fallback procedures are implemented. The remaining residual risk must be demonstrated to be ALARP—As Low As Reasonably Practicable. Continuous monitoring and documentation ensure that safety levels remain acceptable throughout the vessel's operational life. ________________________________________ Slide 7: Operational Context Chapter 8 introduces the operational context that governs MASS operations. The Concept of Operations defines how the vessel and Remote Operations Centre function together. The Operational Design Domain establishes limits relating to weather, sea state, visibility, traffic density, and communication capability. When operating conditions exceed these limits, the vessel must enter a predefined fallback state or minimum risk condition. Comprehensive contingency plans are required to address emergencies such as communication failures, cyber incidents, equipment malfunctions, fire, flooding, and search and rescue situations. ________________________________________ Slide 8: Modes of Operation and Human Oversight The MASS Code recognizes four operational modes. The first is onboard manual operation, where conventional crew control the vessel. The second is remote control from a shore-based Remote Operations Centre. The third is supervised autonomy, where the vessel operates autonomously under human monitoring. The fourth is full autonomy, where onboard systems make