1. Introduction: S-100 – A New Era in Maritime Navigation
Maritime navigation is on the verge of revolutionary changes, marked by the transition to the S-100 standard. This transition represents not just an update to the existing system, but a fundamental change in the approach to collecting, managing, and using hydrographic information. The S-100 standard, developed by the International Hydrographic Organization (IHO), is positioned as a universal hydrographic data model intended to replace the outdated S-57 standard and open new horizons for enhancing the safety and efficiency of seafaring.1 The primary goal of S-100 is to provide a foundation for creating a wide range of digital maritime data and products, including next-generation electronic navigational charts, high-precision bathymetric information, dynamic data on water levels, currents, and navigational warnings.3 This article, based on the user-provided overview and extensive research materials, will detail the key aspects of the S-100 standard, its main product specifications, the implementation schedule dictated by the International Maritime Organization (IMO), and the benefits it brings to the entire maritime industry.
The transition to S-100 is not merely a technical upgrade but a strategic step reflecting general digitalization trends in the maritime industry. It is also a proactive approach to future challenges, such as the development of autonomous shipping and stricter environmental regulations. IHO materials and industry publications have repeatedly emphasized that the implementation of S-100 aligns with the IMO's strategy to reduce greenhouse gas emissions (GHG Strategy) and is an important step towards achieving autonomous navigation.1 The S-57 standard, developed decades ago 5, is no longer capable of adequately supporting the dynamic data and complex information integration required for these advanced applications. Thus, S-100 was developed with a long-term perspective, anticipating the future needs of the industry rather than just addressing the existing limitations of S-57. The standard's flexibility and its ability to integrate diverse datasets are key to supporting these advanced concepts.2 This means that S-100 represents not an endpoint in development, but rather a platform for future innovations in maritime navigation and related fields.

2. From S-57 to S-100: The Evolution of Hydrographic Data Standards

2.1. Legacy and Limitations of the S-57 Standard
For many years, the S-57 standard served as the basis for exchanging digital hydrographic data and creating Electronic Navigational Charts (ENCs).2 It enabled a crucial transition from traditional paper charts to their digital representation in Electronic Chart Display and Information Systems (ECDIS), significantly enhancing the efficiency of navigational activities.
Despite its significant contribution, the S-57 standard, adopted in 1992 5, eventually revealed several substantial limitations, which became particularly evident with the rapid development of digital technologies and the growing demands of the maritime industry.2 Key limitations of S-57 include:
A "frozen" standard: The structure of S-57 and its maintenance regimes make it difficult to implement operational changes and adapt to new data types and technological requirements.6 This limits its ability to evolve with the industry.
Limited support for complex and dynamic data: S-57 was not designed for effective processing of time-varying information, such as real-time tide and current forecasts, or for representing detailed multidimensional bathymetry.2
Data staticity: S-57 is primarily focused on representing a static picture of the maritime environment, which does not always correspond to the dynamic nature of the marine environment.
Insufficient flexibility and interoperability: The standard faces difficulties in integrating data from various sources and for diverse applications beyond traditional navigation, such as for environmental monitoring tasks or port infrastructure management.2
These limitations underscored the need to develop a new, more flexible, and functional standard.

2.2. Concept and Architecture of the S-100 Universal Hydrographic Data Model
In response to the identified limitations of S-57 and the growing needs of the maritime industry, the International Hydrographic Organization (IHO) developed the S-100 standard – the Universal Hydrographic Data Model. This standard was first introduced in 2010 2 and marked a new stage in the development of hydrographic support.
S-100 is not just a replacement for S-57, but a fundamentally new framework structure or data model. It provides a universal basis for developing numerous specialized product specifications, each describing a specific type of hydrographic or related data.2 This is a cardinal difference from S-57, which was primarily focused on one product – Electronic Navigational Charts.
An important feature of S-100 is its development in accordance with the ISO 19100 series of geospatial standards. This ensures its compatibility and ability to integrate with a wide range of geospatial data and systems used in various industries.5 The modular structure of S-100 allows for the creation of specialized product specifications (e.g., S-101 for ENCs, S-102 for bathymetry, S-104 for water levels, etc.) that meet the specific needs of different user groups, such as navigators, port services, offshore platform operators, or organizations involved in environmental monitoring.2
Key components of the S-100 architecture, as described in 7, include:
Conceptual Schema Language (CSL): Based on the Unified Modeling Language (UML) and defines basic data types for specifying geographic information.
Management of IHO Geospatial Information Registries: Includes procedures for maintaining and publishing registries of unique identifiers for geographic, hydrographic, and metadata information items, as well as Feature Concept Dictionary registers.
General Feature Model (GFM) and Rules for Application Schemas: Defines a conceptual model of features, their characteristics, and relationships, as well as rules for developing application schemas.
Metadata Profiles: Based on ISO 19115:2003, ISO 19115-2:2009, and ISO/TS 19139:2007 standards, and are intended for describing, validating, and exchanging metadata for digital geographic data.
The adoption of ISO 19100 standards as the foundation for S-100 is a strategic decision aimed at broader harmonization of geospatial data. This decision extends the utility of S-100 far beyond traditional hydrography and significantly facilitates its integration with other Geographic Information Systems (GIS) and data from related fields. ISO TC211 standards are internationally recognized for geospatial information, which promotes interoperability between different systems and datasets. Consequently, S-100 data can be more easily used not only directly in navigation but also in a wider range of applications, such as coastal zone management, marine spatial planning, ocean scientific research, and environmental monitoring. Such expanded applicability increases the overall value of hydrographic data, promotes its multiple uses, and stimulates cooperation between various maritime and geospatial communities. It also means that investments in S-100 data production can benefit a broader range of stakeholders, enhancing efficiency and contributing to more informed decision-making.

2.3. Key Advantages of S-100 over S-57
The transition to the S-100 standard offers several significant advantages over its predecessor S-57, owing to its modern architecture and flexibility:
Improved data integration and interoperability: S-100 allows for the seamless combination and sharing of various data types, such as bathymetry, topography, marine habitat information, meteorological data, and more, within different applications and systems. This is achieved through the use of standardized data models and compliance with ISO 19100 standards.2
Support for dynamic data: One of the most significant advantages is S-100's ability to integrate information updated in real-time or near real-time. This includes data on tides and water levels (S-104), surface currents (S-111), weather conditions, and other dynamic information, which dramatically improves mariners' situational awareness.1
Enhanced data quality, timeliness, and improved visualization: S-100 introduces improved data quality models and validation rules, ensuring higher accuracy and reliability of navigational information. The standard also facilitates enhanced map display capabilities, including the representation of 3D bathymetry (S-102), additional layers for objects such as buoys and lights, and improved symbology. This makes the ECDIS interface more intuitive and user-friendly.2
Flexibility and adaptability to future needs: The modular structure of S-100 and its compliance with modern geospatial standards ensure easy extensibility and adaptation to support new technologies, data types, and user requirements. This makes S-100 a "living" standard, capable of evolving with the maritime industry.2
Machine-readable catalogues and simplified updating: S-100 provides for the use of machine-readable feature catalogues and portrayal catalogues. This significantly simplifies and potentially automates the process of updating data and ECDIS software, reducing operational costs and the time spent on these procedures.5 For example, updating portrayal catalogues in S-57 based systems could take years and required manual intervention, whereas S-101 (the S-100 based ENC specification) offers a more dynamic process.6
For clarity, the key differences between S-57 and S-100/S-101 are presented in the table below.
Table 1: Comparison of Key Characteristics of S-57 and S-100/S-101

Characteristic
S-57
S-100 / S-101
Data Model
Monolithic, ENC-oriented
Framework, modular, basis for multiple products 2
Dynamic Data Support
Limited/Absent
Built-in, real-time data support (tides, currents, weather) 1
Interoperability
Limited
High, based on ISO 19100, easy integration of various data 2
Update Mechanism
Requires manual intervention, complex
Simplified, machine-readable catalogue support, dynamic updates 5
Data Types
Primarily vector data for ENCs
Supports vector, raster, matrix (grid) data, time series 9
Visualization
2D, standardized symbols
Enhanced, 3D support, dynamic display, flexible symbolization 2
Future Adaptability
Low ("frozen" standard) 6
High, designed for extensibility and support for new technologies 2

This table clearly demonstrates the qualitative leap from S-57 to S-100, providing a structured understanding of the main differences and advantages of the new standard. It becomes evident that S-100 not only addresses the shortcomings of its predecessor but also lays the foundation for a qualitatively new level of information support for maritime navigation, which is the central theme of this section.

3. Key S-100 Product Specifications: Expanding ECDIS Capabilities
The S-100 standard serves as the foundation for creating an entire family of new product specifications, each designed for a specific type of maritime information. These specifications significantly expand ECDIS functionality and provide mariners with a more complete and current picture of the maritime environment.1 Each product specification defines a data model, encoding format, feature catalogue, and, where necessary, a portrayal catalogue for a specific dataset.

3.1. S-101 (Electronic Navigational Charts - ENC): The New Standard for the Base Layer
S-101 is the direct successor to S-57 format Electronic Navigational Charts (ENCs) and is intended to become the primary, fundamental cartographic layer in ECDIS systems operating on the S-100 standard.1 Although S-101 retains most of the characteristics and features familiar to users from S-57, it simultaneously improves existing elements and adds new functions and attributes, creating a more flexible and powerful structure for representing navigational information.5
Key improvements of S-101 compared to S-57 include:
Improved geometry and attribution: S-101 supports more complex geometric representations, such as composite curves, allowing for a more realistic display of real-world objects. Complex attributes, which can be an aggregation of other attributes, are also introduced, providing a more detailed description of features.5
Enhanced relationship-building capabilities: The S-101 data model has an improved ability to model interrelationships between different data objects. This allows for the creation of a more coherent and reality-approximate model of the maritime environment.6
Dynamic portrayal catalogues: Unlike S-57, where updating portrayal catalogues could take years and required significant manual intervention, S-101 provides a more dynamic process for updating and distributing catalogues. An important innovation is the machine-readability of catalogues, which simplifies their integration and updating in ECDIS.5
Simplified data updating: S-101 ENCs will include change highlighting functionality. This means that when a chart is updated, the system will be able to highlight objects that have been added, deleted, or modified. Such a feature significantly saves the mariner's time during route planning and correction.5
Introduction of information types: S-101 allows information to be encoded once and then linked to multiple different features using extended relationship mechanisms. This promotes more efficient data encoding (the "encode once – use many times" principle).6
S-101 ENCs serve as the fundamental navigational layer onto which other information layers, defined within the S-100 family of specifications, such as bathymetry (S-102), water levels (S-104), and currents (S-111), can be overlaid and integrated.6

3.2. S-102 (Bathymetric Surface): Detailing Seabed Topography
The S-102 specification defines the standard for representing bathymetric information as a highly detailed surface of the seabed.1 S-102 data is typically presented as a regular grid of depth values, providing a much more granular and accurate representation of topography compared to the traditional depth contours used in S-57 ENCs.12
The main advantage of S-102 lies in its ability to provide mariners with a significantly more accurate picture of underwater topography. This allows for:
Setting more accurate safety contours: Instead of ECDIS rounding a set safety contour to the nearest available contour line (e.g., 10m or 20m), S-102 allows the use of actual depth values from the grid to construct a dynamic and precise safety contour corresponding to the vessel's draft.12
Opening additional navigable spaces: In areas with limited depths, such as ports, channels, and their approaches, the use of S-102 can reveal areas previously considered unsafe due to the limitations of depth representation in S-57, but which actually have sufficient depth for a specific vessel to pass.12
Improving Under Keel Clearance Management (UKCM): S-102 is a key component for dynamic under keel clearance calculation systems, especially when used in conjunction with S-101 (ENC), S-104 (water level information), and S-111 (surface current information) data.5
Despite the obvious advantages, the implementation of S-102 is associated with some practical aspects. One of these is the potentially large size of S-102 data files, especially for areas with high-resolution bathymetry. During discussions, it was proposed to increase the existing file size limit of 10 MB to at least 200 MB to ensure coverage of sufficiently large areas with acceptable resolution.13 There is also the issue of support for different coordinate systems by ECDIS equipment manufacturers, which can create difficulties when integrating data from different hydrographic offices.13 A critically important aspect in the production of S-102 data is ensuring navigational safety; this means that when generating the depth grid, priority should be given to the shoalest depths, as these are critical for vessel safety.13 Furthermore, digital signatures are envisaged to ensure the integrity and authenticity of S-102 data.13

3.3. S-104 (Water Level Information): Dynamic Accounting for Tides and Water Level Variations
The S-104 specification is designed to provide information on water levels, including data on tides and other sea level fluctuations.1 This information can be presented as gridded water level surfaces (grids of water level values) and may contain both real-time observation data and forecasts calculated using hydrodynamic models.14
The key role of S-104 is to replace the static point tidal predictions traditionally used in navigation with dynamic water level surfaces that can be directly integrated and displayed in ECDIS.14 This provides the following advantages:
Dynamic Under Keel Clearance (DUKC) calculation: S-104 is a critically important component for DUKC. By overlaying S-104 data on the S-102 bathymetric surface and the S-101 base chart, ECDIS can calculate the actual water depth in real-time or based on forecasts, taking into account the current or expected tidal height.5 This allows mariners to make more informed decisions regarding passage safety.
Optimization of port operations: The use of accurate water level data can help expand so-called "tidal windows" – periods when the depth is sufficient for a vessel to safely enter or leave a port. This, in turn, can reduce vessel waiting times at anchorage and optimize their loading, as there is greater confidence in available depths.14
Enhanced situational awareness: Visualizing dynamic changes in water level directly on the ECDIS screen gives mariners a more complete understanding of current and predicted conditions, which is especially important when maneuvering in areas with significant tidal phenomena.14
Trials conducted using S-104 data, for example, in the Port of London, demonstrated how visualizing tidal height in relation to the seabed in different parts of the river helps pilots make decisions about starting berthing operations or planning maneuvers in narrow passages.14

3.4. S-111 (Surface Current Information): Real-Time Current Data
The S-111 specification defines the standard for providing data on the direction and speed of surface currents.1 This data can be supplied in real-time or be the result of forecasts obtained using hydrodynamic models, and is usually presented as a gridded coverage with varying spatial resolution.15 The "surface" in this context is defined as the water layer up to several meters deep from the actual water surface.16
S-111 information plays an important role in enhancing the safety and efficiency of maritime transport:
Optimization of maritime transport: Knowledge of current or predicted currents allows mariners to adjust the vessel's course and speed. This can lead to significant fuel savings by utilizing favorable currents or minimizing resistance from adverse currents, as well as reducing emissions of harmful substances into the atmosphere.10 Studies have shown the economic benefits of using S-111 in terms of reduced fuel consumption and transit time.11
Assistance during maneuvering: In confined waters, such as ports, channels, or narrow straits, information about currents is critically important for safe maneuvering. S-111 can help pilots and captains account for the vessel's drift due to currents, especially when performing complex operations like berthing or passing near other vessels or obstacles.14
Component for integrated navigation management: S-111 data, along with S-101 (ENC), S-102 (bathymetry), and S-104 (water level), is an important input parameter for dynamic under keel clearance management (UKCM, S-129 specification) systems.5
The operational version S-111 Edition 2.0.0 was published at the end of 2024, paving the way for its practical application.16

3.5. S-124 (Navigational Warnings): Integrated and Geospatial Alerts
The S-124 specification is designed for encoding and transmitting urgent information important for the safety of navigation, such as navigational warnings (NAVAREA, coastal, and local warnings).15 S-124 is a vector product that describes not only the textual content of the warning but also its geographical extent, i.e., the area to which the warning applies (e.g., area of works, location of a malfunctioning navigational aid, etc.).17
Key advantages of S-124 compared to traditional methods of disseminating navigational warnings (e.g., NAVTEX or SafetyNET text messages) include:
Graphical display in ECDIS: S-124 allows navigational warnings to be displayed directly on the electronic chart as a graphical overlay layer. This significantly improves the mariner's perception of the information, as they can visually assess the location and boundaries of a hazardous area or restricted zone in relation to their vessel and planned route.17
Improved filtering and automatic alerting: The structured data format of S-124 enables ECDIS to perform more intelligent filtering of warnings. For example, the system can automatically select only those warnings relevant to the vessel's current or planned route, or those active during a specific period. This helps avoid information overload and reduces the risk of missing genuinely important information.18 Automatic alerts when approaching a warning area are also possible.
Enhanced situational awareness: Quick and clear access to information about hazards and restrictions contributes to timely and correct decision-making by the mariner.
Potential for backward compatibility: S-124 is designed with the possibility of using its data to generate traditional text messages for NAVTEX and SafetyNET systems during production. This allows for maximum dissemination of safety-critical information through various communication channels during the transition period.17
It is important to note that for effective dissemination of S-124 data, which is transmitted in S-100 format (e.g., GML or ISO8211), new communication systems such as NAVDAT or VDES will be required, as existing NAVTEX and SafetyNET systems, operating with text (telex) format, will not be able to transmit S-124 data.18 The S-124 specification is expected to be approved in early 2025.4

3.6. S-129 (Under Keel Clearance Management - UKCM): Dynamic Safety Control
The S-129 (Under Keel Clearance Management - UKCM) specification is designed for the exchange of digital data related to the calculation, monitoring, and management of a vessel's minimum under keel clearance.1 This is a critically important aspect of navigation safety, especially when sailing in areas with limited depths, such as ports, channels, rivers, and shallow coastal zones.
S-129 is not an isolated product; its main value lies in its ability to integrate and use data from other S-100 product specifications to perform complex calculations. Such products include:
S-101 (Electronic Navigational Charts) for basic cartographic information.
S-102 (Bathymetric Surface) for highly detailed seabed topography data.
S-104 (Water Level Information) to account for dynamic changes in water level (tides, storm surges).
S-111 (Surface Current Information) to account for the influence of currents on the vessel's draft and maneuverability.
Weather data (e.g., from S-41x series specifications) and vessel route data (e.g., S-421 Route Plan) may also be used.5
UKCM systems using S-129 data are capable of performing dynamic modeling of under keel clearance, taking into account the specific characteristics of a particular vessel (draft, beam, length, speed, stability characteristics) and current or predicted environmental conditions (tidal height and time, wind strength and direction, waves, river currents, etc.).
Key functional capabilities and advantages of S-129:
Provision of transit window options: A UKCM service can calculate and provide several options (windows) for the safe passage of a vessel through a shallow water area, identifying periods when the tidal height will be sufficient.21
Dynamic updating of the UKC plan: The UKC passage plan can change depending on updates to weather forecasts, actual water level data, or changes in the vessel's characteristics (e.g., change in draft after loading/unloading). The system allows the vessel to adjust its speed to arrive at a critical point on the route at the optimal time.21
Unified picture of the navigational situation: The UKC plan, calculated using S-129, can be displayed on both the main onboard navigation system (ECDIS) and a portable pilot unit (PPU). This ensures a common understanding of the planned maneuver and current situation among the entire bridge team and the pilot.21
Real-time monitoring: The UKCM service can track the vessel's position (e.g., via AIS) and send updates to the vessel's UKC plan in real-time or near real-time, considering the vessel's actual speed and current conditions. Mariners can see areas calculated as non-navigable or almost non-navigable on their screens.21
Increased safety and situational awareness: The use of S-129 significantly enhances navigation safety in areas with limited depths and improves overall situational awareness on the bridge.21 Operational trials have shown that displaying non-navigable areas increases navigators' attention to them, and the time factor (displaying conditions ahead) improves preparation for maneuvers.

Overview of Key S-100 Product Specifications (S-101, S-102, S-104, S-111, S-124, S-129) indicating their main purpose and advantages.

S-101
Electronic Navigational Charts (ENC)
New generation base cartographic layer, replacing S-57 ENC 1
Improved geometry, dynamic catalogues, easy updates, basis for other S-100 layers 5

S-102
Bathymetric Surface
Highly detailed information on seabed topography (grid) 1
Accurate safety contours, opening new navigable spaces, basis for UKCM 12

S-104
Water Level Information
Dynamic data on tides and water levels (grid) 1
Dynamic UKC, extension of tidal windows, load optimization 14

S-111
Surface Current Information
Real-time data on current direction and speed (grid) 1
Voyage optimization, fuel savings, maneuvering assistance, component for UKCM 11

S-124
Navigational Warnings
Transmission of urgent navigational information 15
Graphical display in ECDIS, improved filtering, enhanced situational awareness 17

S-129
Under Keel Clearance Management
Data exchange for dynamic UKC calculation and monitoring 15
Integration of dynamic data (S-101/102/104/111), increased safety in shallow waters, common picture for bridge and pilot 21

The true power of S-100 product specifications lies not so much in their individual capabilities as in their synergistic integration. The combination of S-101 (base chart), S-102 (detailed bathymetry), S-104 (water level information), and S-111 (current data) to provide dynamic under keel clearance management via S-129 is a prime example of this.5 This demonstrates a qualitative shift towards holistic, data-fusion-based navigation. Such an approach represents a paradigm shift from using predominantly static S-57 format charts to actively managing multiple dynamic, interconnected information layers. Future ECDIS systems will need to evolve into powerful platforms for data fusion and analysis. Consequently, mariners will require additional training and skill development to effectively interpret and use these combined data layers, which significantly differs from working with the relatively static data of S-57 charts.
Furthermore, the development and approval timeline for various S-100 products suggests a phased implementation of functionalities. Phase 1 products, such as S-101, S-102, S-104, S-111, S-129, are primarily focused on route monitoring, while Phase 2 products (e.g., S-122 Marine Protected Areas, S-123 Marine Radio Services, S-127 Marine Traffic Management, S-131 Marine Harbour Infrastructure) will concentrate on route planning.4 The first operational standards within S-100 have already been adopted, but the development and approval of other specifications are ongoing.1 This indicates a strategy of gradual implementation, likely driven by the complexity of developing each product and the need for thorough testing. Consequently, users and equipment manufacturers must understand that not all announced S-100 features and products will become available simultaneously. The full benefits of the new ecosystem will be realized progressively, which needs to be considered when planning equipment and software upgrades, as well as developing training programs. Expectations regarding the timing of specific capabilities should be realistic.

4. IMO Resolution MSC.530(106): The Roadmap for S-100 Implementation

4.1. Role and Significance of the IMO Resolution
The adoption by the International Maritime Organization (IMO) of the revised Resolution MSC.530(106) on Performance Standards for Electronic Chart Display and Information Systems (ECDIS) is a key regulatory step formalizing the maritime industry's transition to the S-100 standard. This resolution was adopted at the 108th session of the Maritime Safety Committee (MSC) in May 2024.1 It should be noted that the original text provided by the user mentioned resolution MSC.530(106) without specifying the session; however, more recent sources 1 clarify that it refers to the 108th session of MSC in May 2024, which is accepted as current information.
This resolution is of immense importance because it:
Highlights global commitment to S-100 implementation: The IMO's decision, as a specialized UN agency responsible for the safety and security of shipping and the prevention of marine pollution by ships, gives the transition to S-100 official international status.1
Establishes the regulatory framework for S-100 use: The resolution defines the performance standards for next-generation ECDIS, which must be capable of processing and displaying data compliant with S-100 product specifications.
Introduces mandatory requirements and timelines: Most importantly, the resolution sets specific dates for the phased implementation of S-100 compliant ECDIS on ships.10
Thus, Resolution MSC.530(106) serves as the official "roadmap" for the entire maritime industry, guiding the efforts of equipment manufacturers, software developers, hydrographic offices, shipping companies, and training centers towards the transition to the new technological platform.

4.2. Key Dates and Transition Stages
IMO Resolution MSC.530(106) establishes a clear timeline for the implementation of S-100 compliant ECDIS:
From January 1, 2026: The use of ECDIS compliant with the S-100 standard becomes permissible (legally allowed). This means that vessels equipped with such systems will be able to legally use them for navigation, provided that relevant S-100 data (particularly S-101 format ENCs) are available.1 This stage allows manufacturers and early adopters to begin implementing and testing the new systems.
From January 1, 2029: All new ECDIS systems installed on ships (both on newbuilds and when replacing existing equipment on operational vessels) must comply with the updated IMO ECDIS Performance Standards. This means they must be fully compatible with the S-100 standard and capable of processing relevant S-100 data products.1
These dates are important milestones defining the pace of navigation equipment modernization in the global merchant fleet.

4.3. The Concept of "Dual-Fuel" ECDIS and the Phasing Out of S-57
To ensure a smooth transition from the S-57 standard to S-100, and considering that global coverage with new format data will take time, the IMO introduced the concept of so-called "Dual-Fuel" ECDIS.
"Dual-Fuel" Requirement: By January 1, 2029, all ECDIS (this requirement applies to all new installations, and likely to existing systems undergoing significant upgrades) must have "dual-fuel" capability. This means the ECDIS system must be capable of simultaneously displaying and working with both old S-57 format data and new S-100 format data (including the S-101 ENC base layer and other relevant layers like S-102, S-104, S-111, etc.).10
Transition Period: The "dual-fuel" stage represents a transition period. It is necessary so that vessels can continue safe navigation using existing S-57 chart coverage while gradually transitioning to S-100 data as it becomes available from national hydrographic offices.
Phasing out of S-57: The complete phasing out of the S-57 standard and the cessation of its support by hydrographic offices (i.e., discontinuation of updates for S-57 ENCs) is expected around 2034.10 This date is an important addition to the information provided in the user's initial text and indicates the end-of-life for the S-57 standard.
The "Dual-Fuel" ECDIS requirement is a pragmatic approach to a complex global technological transition. It acknowledges that creating worldwide S-100 data coverage is a massive task for hydrographic offices, requiring significant time and resources. Instantly replacing all S-57 ENCs with S-101 worldwide is impossible. Thus, "Dual-Fuel" ECDIS represents a compromise solution, allowing the benefits of S-100 to be utilized in areas where new format data is already available, without ceasing navigation in areas still covered only by S-57 charts. However, this also places a certain burden on equipment manufacturers, who need to develop and maintain software capable of working with two different data formats. For users (mariners), this means a temporary period during which they may have to manage two types of cartographic data and learn new update procedures. The success of this transition phase directly depends on the coordinated efforts of the IMO, IHO, national hydrographic offices in producing S-100 data, and navigation equipment manufacturers.

S-100 Implementation Timeline according to IMO Resolution MSC.530(106)

May 2024
IMO adopts revised Resolution MSC.530(106) on Performance Standards for ECDIS (MSC 108th session)

January 1, 2026
Permissible use of S-100 compliant ECDIS
User's initial text, 1

January 1, 2029
All new ECDIS systems must comply with S-100 standards (including "Dual-Fuel" capability for all systems subject to the requirement)

By 2034
Full phasing out of the S-57 standard

This provides a clear and concise overview of the regulatory timeline for the transition to S-100, which is critically important for planning activities by all maritime industry stakeholders, including shipping companies, equipment manufacturers, training centers, and hydrographic offices.

5. Advantages and the Future of Navigation with S-100
The implementation of the S-100 standard and its associated data products promises to bring numerous benefits to the maritime industry, affecting safety of navigation, economic efficiency, environmental aspects, and readiness for future technologies.

5.1. Enhanced Safety of Navigation
Safety is the top priority in the maritime industry, and S-100 makes a significant contribution to its enhancement:
Improved situational awareness: A key advantage of S-100 is the ability to integrate diverse dynamic data into a single ECDIS system. The mariner gains access to a more complete and current picture of the surrounding environment, including highly detailed depths (S-102), current and predicted water levels (S-104), surface current data (S-111), graphically represented navigational warnings (S-124), and potentially weather and ice information (e.g., S-411, S-412).1 This allows for more informed navigational decisions.
More accurate safety contours and Under Keel Clearance Management (UKCM): The combination of S-101, S-102, S-104, S-111, and S-129 products allows ECDIS to dynamically calculate and display safe navigation zones, considering real conditions and vessel characteristics. This is particularly important in areas with limited depths, where precise knowledge of under keel clearance is critical.5 So-called "tide-aware ENCs" with dynamic safety contours will become a reality.10
Reduced alarm fatigue: In existing S-57 based ECDIS systems, some objects or information are encoded in a way that can cause unnecessary or false alarms (e.g., extensive "caution areas"). S-101 and other S-100 products offer more precise object encoding and the ability to use so-called "information objects," which provide information without generating superfluous warnings. This can help reduce the cognitive load on the mariner and lessen "alarm fatigue," allowing focus on genuinely important signals.9
Improved navigational warnings: The S-124 specification allows for the graphical display of navigational warnings on the chart and the application of intelligent filters to select the most relevant information. This makes warnings more understandable and easily interpretable compared to traditional text messages.18

5.2. Increased Efficiency and Voyage Optimization
In addition to enhancing safety, S-100 opens up opportunities for significant increases in the economic efficiency of maritime transport:
Optimization of vessel loading: More accurate knowledge of actual depths and dynamic calculation of under keel clearance (thanks to S-102, S-104, S-129) can allow vessels to take on more cargo without compromising safety, especially in ports and their approaches where depth is a limiting factor. It is estimated that for a large container ship (about 400m long), every additional 10 cm of available under keel clearance could mean the ability to load up to 100 additional containers (TEU), directly impacting voyage profitability.1
Fuel savings and emission reductions: Using surface current data (S-111) and potentially weather data to optimize routes and vessel speed can lead to substantial fuel consumption reductions. This not only cuts operational costs but also reduces emissions of greenhouse gases and other harmful substances into the atmosphere.10
Time savings and expansion of operational windows: Dynamic accounting for tides and water levels (S-104) can allow vessels to enter ports or transit through channels within wider time frames ("tidal windows"). This reduces waiting times at anchorage, decreases associated costs (e.g., for anchoring), and increases the overall throughput of ports.3
More efficient data exchange and updates: Machine-readable catalogues and standardized S-100 data formats simplify and accelerate the processes of updating navigational information onboard. This reduces labor costs and the likelihood of errors associated with manual input or complex update procedures.5

5.3. Reduced Environmental Impact
The environmental aspect is becoming increasingly important in the maritime industry, and S-100 contributes to reducing the negative impact of shipping on the environment:
Compliance with IMO's GHG strategy: The implementation of the S-100 standard and its associated capabilities for voyage optimization (route, speed, loading) directly contribute to achieving the International Maritime Organization's goals for reducing greenhouse gas emissions from ships.1
Reduced carbon footprint: Lower fuel consumption, achieved through the use of dynamic data (e.g., S-111 for current accounting, S-104 for port entry optimization), leads to a direct reduction in emissions of CO2​ and other harmful substances such as sulfur oxides (SOx​) and nitrogen oxides (NOx​).10 This makes shipping more environmentally responsible.

5.4. A Step Towards Autonomous Navigation and Improved Cybersecurity
The S-100 standard lays the groundwork not only for improving existing practices but also for implementing future technologies:
Foundation for autonomous navigation: S-100 is considered a critically important technological element and necessary data infrastructure for the development and safe implementation of autonomous and remotely operated navigation technologies.1 Autonomous systems require a vast amount of accurate, current, standardized, and machine-readable data about the surrounding marine environment to make real-time decisions. The S-57 standard cannot provide this level of detail and dynamism. S-100, with its ability to integrate various dynamic information layers (S-102, S-104, S-111, S-124, etc.), creates the necessary information environment for the safe and effective operation of autonomous vessels. Thus, investments in the transition to S-100 will have long-term returns beyond immediate improvements in traditional navigation, positioning the industry for future technological shifts and increased automation.
Enhanced cybersecurity: As vessels become increasingly dependent on digital systems and data flows, cybersecurity issues come to the forefront. Standardized S-100 data formats facilitate the application of uniform and reliable security measures, such as encryption and authentication, across all systems and data products. S-100 products are developed with modern cybersecurity requirements in mind, including the use of digital signatures to confirm data source authenticity and ensure data integrity (protection against unauthorized modification).1 For example, digital signature mechanisms are provided for S-102 data.13 This proactive approach to data security is crucial for maintaining trust in digital navigation systems and mitigating risks associated with cyberattacks or corruption of critical navigational information. This is especially important for future autonomous operations, where data integrity is paramount for safety.

6. Conclusion: Confidently Moving into the Future of Maritime Navigation
The transition to the S-100 standard marks a fundamental shift in maritime navigation, ushering in a new era of digital technologies and integrated data. This is not merely a technical update but a comprehensive transformation affecting all aspects of collecting, processing, disseminating, and using hydrographic and related information. As has been detailed, S-100 and its associated product specifications offer significant advantages over the outdated S-57 standard.
Key benefits from S-100 implementation include a substantial enhancement of maritime safety through improved situational awareness and dynamic management of navigational parameters; increased economic efficiency due to optimized vessel loading, fuel savings, and reduced voyage times; a reduction in negative environmental impact in line with global environmental initiatives; and the creation of a technological foundation for future innovations such as autonomous shipping, alongside strengthened cybersecurity for maritime operations.
The successful development and widespread adoption of the S-100 standard are the result of, and further necessitate, close collaboration among the International Hydrographic Organization, IHO Member States, the International Maritime Organization, industry (equipment and software manufacturers), academia, and other stakeholders.1 This collective approach is essential to overcome the challenges associated with such a large-scale transition.
It is important to understand that the development of the S-100 ecosystem is an ongoing process. The maritime community can expect the emergence of new product specifications, improvements to existing ones, and an expansion of the functional capabilities of navigation systems. The implementation timeline defined by IMO Resolution MSC.530(106) sets clear deadlines, but its realization will require coordinated efforts and investments.
The successful implementation of S-100 will largely depend on several key factors. Firstly, international cooperation in developing standards, producing, and harmonizing data. The global nature of the maritime industry demands concerted approaches. Secondly, continuous investment in the production of next-generation hydrographic data by national hydrographic offices. Producing S-100 data, especially high-resolution bathymetry (S-102) or dynamic data (S-104, S-111), is a resource-intensive process.2 Thirdly, the development and implementation of comprehensive training programs for end-users – mariners, pilots, VTS operators, and other personnel.10 New, more complex systems and multi-layered data require new knowledge and skills for their effective and safe use. Technology alone is insufficient; a coordinated ecosystem approach is needed to fully realize the vast potential of S-100.
In light of this, all maritime industry stakeholders – shipping companies, equipment manufacturers, software developers, training centers, and, of course, seafarers themselves – should actively prepare for this transition. This includes planning for the upgrade of shipboard systems, investing in personnel training, and mastering the new capabilities offered by the S-100 standard. Only then can we confidently move into the future of maritime navigation, which promises to be safer, more efficient, and technologically advanced.