Challenge
As container ships have grown larger and stacks taller, traditional stowage models have struggled to ensure safety and maximise loading efficiency. Incidents of container loss at sea remain a concern, with 576 containers lost in 2024 alone. Though low compared with global traffic, these losses carry serious crew, environmental and reputational consequences.
Operators face two core challenges:
- Securing containers under increasingly complex motion forces and rolling conditions
- Maximising cargo volume and profitability, and reducing emissions, without exceeding safety margins.
Legacy assumptions in stack modelling, such as rigid corner connectivity, no longer reflect modern operational realities. New methods are needed to accurately simulate stack dynamics and vessel-specific rolling behaviour across diverse sea conditions. These risks are amplified on today’s larger vessels, which are more susceptible to parametric and synchronous rolling caused by hull proportions and stability characteristics
Solution
Lloyd’s Register (LR) has developed a future-ready container stowage ecosystem that sets a new benchmark for operational safety and performance in container transport:
- BoxMax notation, accessed through the application LashRightUX, delivers route- and voyage-specific stowage optimisation
- RDA notation, accessed through the application RollRight, provides vessel-specific roll behaviour modelling and real-time alerts that help crews anticipate and avoid hazardous sea states.
Approach taken
LR’s methodology combines high-fidelity simulation with vessel-specific analysis. LashRightUX, first released in 2016 and updated in July 2025, models the forces on container stacks, capturing non‑linear motion and structural interaction. Integrated into third-party tools, it now supports vessel design and lashing software globally, and is used by ship designers, securing providers and software developers beyond LR’s own approval services. Together, these capabilities form the analytical foundation of the BoxMax notation.
BoxMax notation applies where onboard lashing software is approved under LR rules, with loadability enhancements derived from route-specific data and voyage conditions. Optional supplements enable optimisation for different routes, sea states, short voyages and motion forecasts.
RDA notation is issued when LR’s RollRight software is used to predict ship roll behaviour to identify hazardous sea states. The system provides real-time guidance based on loading conditions and wave interactions. It includes two assessment levels, and may recognise anti-roll devices within the vessel’s motion model. RollRight meets LR’s functional requirements for onboard roll
assessment software, predicting roll behaviour, assessing real-time risks and guiding crews before thresholds are reached.
With these systems now embedded across design and onboard use, the framework is driving measurable operational change.
LR’s service differentiators
- LR bridges class-rule development with applied digital analysis, advancing container safety through a combination of technical depth and software validation
- By embedding the BoxMax and RDA notations, and directly within its classification framework, LR creates a continuous link between design verification and operational assurance
- BoxMax and RDA notations are accessible through LashRightUX and RollRight digital applications. The approach integrates proven structural dynamics expertise with digital verification, ensuring stowage and roll-risk tools align with class integrity standards
- Lloyd’s Register is a member of the Lashing Exchange Format (LXF) Consortium, which represents 70% of the container ship segment and drives industry-wide collaboration to standardise data sharing for stowage design and approval, while improving digital integration across the sector
Strategic advantages
Through accurate modelling of stack forces and rolling risk, operators can now increase loadability with confidence and reduce the risk of container loss,
delivering safer, more profitable voyages. These outcomes mark a clear shift in industry practice, from conservative, assumption-based limits toward
dynamic, data-driven stowage decisions integrated into vessel operations.
Recent research indicates that parametric and synchronous roll resonance are among the primary causes of container ship incidents in heavy weather, often leading to container loss. The Navis Lashing Monitor, powered by Lloyds Register RollRightSolver, provides the onboard crew with valuable insights to identify potential roll risks and recommend preventive actions to safeguard both the vessel and its cargo.
