# Modeling of Historical Marine Casualty on S-100 Electronic Navigational Charts
## 1 Introduction  
In the past, maritime navigation primarily relied on paper nautical charts and the accumulated experience of navigators to determine safe routes. With the advancement of digital technology, traditional paper charts were gradually replaced by ENCs, enabling ships to access and interpret hydrographic information more efficiently and accurately. To support this transition and to standardize the digital encoding of chart data, the IHO developed the S-57 standard [1]. S-57 facilitated the electronic exchange of chart information and served as the basis for the production and distribution of ENCs used in Electronic Chart Display and Information Systems (ECDIS). However, S-57 was designed with a fixed data structure tailored specifically for static chart features, and its architecture lacked the flexibility to accommodate new and dynamic types of maritime information, such as time-dependent environmental data, traffic updates, and complex metadata. These limitations became increasingly apparent with the growing demand for integrated and interoperable navigational services. As a result, the IHO introduced the S-100 UniversalHydrographic Data Model (UHDM) as a more versatile and extensible framework for the future of maritime data exchange [2]. Following the adoption of S-100, initial development efforts focused on creating data models that represent fundamental chart features previously supported by S-57. These models provide the core base layer of digital navigational information and are essential for ensuring safe passage. Once these foundational data models were in place, additional efforts were made to develop a range of supplementary data models aimed at enhancing navigational safety. These include models for representing bathymetry, tidal information, surface currents, and navigational warnings. Many of these models are now being applied in digital chart systems to support both real-time monitoring and voyage planning [3; 4; 5]. Despite this expansion, a significant gap remains within the current set of S-100-based data models: the absence of a model for representing marine casualty. In maritime operations, past incidents such as groundings, collisions, and structural failures often contain valuable insights into navigational risks. However, these insights are typically passed down informally through the personal experience of captains and navigators, without being structured or made accessible in digital navigation systems. In contrast, the land transportation sector systematically utilizes both real-time and past incident data to identify high-risk areas and enhance safety outcomes [6; 7; 8; 9; 10]. If casualty data were structured and integrated within the S-100 framework, it could serve as a valuable resource for route planning, risk analysis, and safety management. While several prior studies have attempted to organize casualty data for archival or analytical purposes, their outputs were not designed to be interoperable with the S-100-based environment and thus cannot be used within electronic navigational systems [11; 12]. To address this gap, this study proposes a new data model for representing and exchanging marine casualty, developed in full alignment with the S-100 modeling methodology. The proposed model defines both a data storage structure--interpretable by both humans and machines--and a portrayal structure that specifies how this data can be visualized within electronic chart systems. To examine the proposed data model, a case study was conducted using real-world casualty records from the Global Integrated Shipping Information System (GISIS) of the International Maritime Organization (IMO). The goal was to verify S-100 compliance and assess its potential use in navigational data systems. By introducing a structured approach to managing marine casualty, this study contributes an extension to the S-100 framework that addresses an area previously not covered by existing data models.