LR's first Approval in Principle (AiP) for a submarine design was awarded earlier this year to Hanwha Ocean, with the Submarine Assurance Framework being used to assess key elements of the concept.

Lloyd’s Register (LR) has expanded its Submarine Assurance Framework, helping navies, submarine designers and shipyards demonstrate structural safety, design robustness and technical confidence across submarine programmes.

The publication of Volume 2: Submarine Structures, which came into effect on 1 July 2026, expands LR’s goal-based assurance framework for submarines and supports the independent verification of submarine structures against project specifications, applicable rules, codes and standards.

Submarines cannot be assured through traditional classification

Unlike surface vessels, submarines cannot be assured through traditional classification alone, creating a need for a structured and independent approach that reflects their unique operational and engineering challenges.

LR’s Submarine Assurance Framework addresses this by applying classification principles in a flexible, goal-based way that is tailored to submarine programmes, combining LR’s technical expertise, naval experience and risk-based assurance capability.

Related: LR awards its first submarine AiP to Hanwha Ocean

 New construction programmes

The framework can support new construction programmes, in-service assurance, supply chain assurance, technology qualification, life extension and decommissioning. It provides a clear route for demonstrating that a submarine has been designed, built and maintained in accordance with agreed safety objectives and performance requirements.

Volume 2 establishes requirements and guidance for the structural assurance of submarines, addressing the unique challenges associated with the pressure hull, bulkheads and other structural elements operating in demanding underwater environments.

Related: LR: New project targets low-carbon future for European short-sea trade

Submarine capability programmes

The update comes as naval procurement and submarine capability programmes continue to grow in strategic importance worldwide. As projects become more ambitious and technologically advanced, independent assurance is becoming increasingly important in helping stakeholders demonstrate asset safety, readiness and technical credibility while improving operational availability.

 Submarine Structures is an important step

Matthew Palmer, Global Director, Submarine Business at Lloyd’s Register, said: “Submarine assurance requires a different approach. These are highly complex assets, operating in demanding environments, and navies and builders need confidence that their designs, structures, systems and supporting evidence can stand up to rigorous independent scrutiny.

“The publication of Volume 2: Submarine Structures is an important step in the development of LR’s Submarine Assurance Framework. It gives navies, designers and shipyards a clearer way to demonstrate structural safety and supports the broader assurance process from early design through to operation and life extension.”

 First Approval in Principle (AiP)

Earlier this year, LR awarded its first Approval in Principle (AiP) for a submarine design to Hanwha Ocean, using the Submarine Assurance Framework to assess key elements of the concept. The project demonstrated how the framework can provide an independent and transparent route to evaluating emerging submarine technologies at an early stage of development.

About: Lloyd’s Register (LR)

Lloyd’s Register (LR) is a global maritime classification society and professional services organization that sets safety and technical standards for ships, offshore structures, and critical infrastructure. Founded in 1760 at Edward Lloyd's coffee house in London, it is owned by the Lloyd's Register Foundation, a UK charity that funds science and engineering research

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