Navigational Risk from the Desynchronization of Safety Information Across Chart Systems on SOLAS and Non-SOLAS Vessels

The regulatory disparity in nautical chart carriage requirements between SOLAS and non-SOLAS vessels poses a systemic risk for maritime safety. This study analyzes maritime traffic and grounding accidents in the East Adriatic Sea to examine the empirical patterns associated with this risk and to quantify this risk. Analysis of 2,699,930 vessel arrivals in Croatian ports (2012–2020) reveals that non-SOLAS vessels dominate traffic, outnumbering SOLAS vessels by factors of 3.44 (cargo) and 13.92 (passenger). Correspondingly, over 92% of 170 recorded groundings (2017–2019) and 90.6% of 202 groundings (2020–2025) involved non-SOLAS ships, predominantly during favourable weather conditions. The core problem is identified as the desynchronization in disseminating Maritime Safety Information (MSI) across official and unofficial chart systems, leading to inconsistent situational awareness. This risk is formalized through a conceptual objective function modelling the time delay in MSI updates across different chart production chains. These quantitative metrics demonstrate that the current regulatory gap exposes the majority of maritime users to a reduced safety standard, directly affecting risk management at the operational and regulatory levels. To minimize this delay and enhance navigational safety, the paper proposes a dual-pathway amendment: extending the ECDIS/ENC mandate to all SOLAS ships and establishing a new framework mandating the use of official ENC data within Electronic Chart Systems (ECS) for non-SOLAS vessels. This study is intended as a system-level analysis of regulatory and informational asymmetry rather than as a full accident-causation investigation. The findings should therefore be interpreted as exploratory and policy-relevant, with caution regarding direct causal inference for individual incidents. The proposed measures are essential to synchronize critical maritime safety information across all maritime users.