Exploring S-102 and the Future of Maritime Navigation

From route planning and optimization to safe maneuvering in ports and coastal waters, bathymetric data plays a fundamental role in maritime navigation. Mariners rely on water depth information and an understanding of seabed topography to make informed decisions throughout a voyage. Ensuring mariners can access accurate bathymetric information is a key priority across the hydrographic community.

To support this objective, the International Hydrographic Organization (IHO) has developed a new product specification for bathymetric data as part of its broader S-100 ecosystem. Known as S-102, this specification allows for the creation and exchange of high-resolution bathymetric surface data in a regular, gridded format.

For navigation, S-102 data will be used to create bathymetric surface data layers for next-generation S-100 Electronic Chart Display and Information Systems (ECDIS). These layers will contain high-resolution seafloor profiles that can be overlaid on S-101 Electronic Navigational Charts (ENCs), the new specification for ENCs that will replace the current S-57 standard.

By providing a more detailed view of the seafloor, S-102 offers opportunities to improve navigational safety and efficiency.

Why S-102 matters for navigation

Today, mariners set a safety contour on their ECDIS based on their vessel’s draught, which delineates the safe navigable space. However, current ECDIS are limited to the predefined contour limits of S-57 ENCs, which are typically only available at broad intervals. Providing higher-density bathymetric information, S-102 enables more precise, vessel-specific safety contours to be set.

For bridge teams, more precise safety contours and an improved awareness of the true navigable space around their vessels can help to increase safety when navigating in shallow, confined or highly congested waterways. Greater confidence in the true depth of water underneath a vessel’s keel can also support vessel operators to make more informed cargo loading decisions, helping to improve voyage efficiency.

Integration of S-102 with other interoperable S-100 data layers can provide further advantages. For instance, combining S-102 with S-104, the data layer for water level information, can support dynamic adjustment of under keel clearance calculations in near real time. This enables safety contours to be automatically adjusted with changing tides. More precise safety contours could also help reduce unnecessary alarms in situations where mariners know there is sufficient under keel clearance, supporting a more focused bridge environment.

Evaluating S-102 in practice

To help understand how S-102 and other data layers perform in practice, organizations across the maritime sector have been conducting comprehensive trials. As part of this work, the UK Hydrographic Office (UKHO) has been collaborating with a range of partners to evaluate several S-100 data standards, including S-102, in realistic navigational scenarios using full mission bridge simulators.

These trials have brought together marine pilots and commercial bridge teams from leading tanker, LNG and bulk fleets to provide insights into how S-100 influences navigational decision making. By working with active seafarers in structured, simulator environments, the trials have gathered practical feedback from a range of operational perspectives and enabled direct comparisons between S-57 and S-100 data.

One of the key findings from these trials has been the ability of S-102 to combine with other data layers to improve route planning. Using S-57, trial participants adopted relatively conservative routing approaches and were only able to validate 5 out of 20 planned waypoints. After introducing S-100 data layers, crews were able to identify additional navigable water and validated all 20 waypoints as safe. In practice, this could help mariners identify safe, efficient routes that may not be apparent with S-57 alone.

The trials also highlighted how S-102 can add value in high-risk scenarios, including pilotage and berthing. For instance, participants noted how integrating S-102 with the S-111 surface currents layer can help improve awareness of the impacts of tidal flows, ebbs and directional shifts in areas with reduced safety margins. This can help mariners to better anticipate vessel behavior and improve precision when maneuvering in complex environments.

Across both voyage planning and navigation, the interoperability of S-100 layers was cited as a key advantage. By integrating multiple data sources, crews could avoid cross-referencing materials such as tide tables and current references, improving efficiency. Similarly, consolidating safety-critical information into a single view helped to improve mariners’ awareness of the environment and increase confidence during navigation.

Alongside evaluating the performance of S-100, the trials also identified several considerations for successful implementation. This included user interface optimizations for next-generation ECDIS to improve usability. For example, being able to toggle data layers on and off to tailor displays to specific situational requirements and user preferences. The trials also underlined the need for practical, scenario-based training and clear operational guidance to help mariners understand how S-100 integrates information in ways that can reduce, rather than increase, the amount of interpretation required on the bridge.

Supporting autonomous navigation systems

In addition to transforming the way navigational information is used by mariners, the S-100 framework has also been developed to provide data in machine-readable formats, allowing for automated processing and integration with digital systems. For remotely operated and autonomous vessels, this will enable pre-existing hydrographic data and on-board sensor data to be compared in real time, facilitating autonomous decision-making.

This potential of S-100 to support uncrewed and autonomous vessels has already been shown. In 2022, the Mayflower Autonomous Ship became one of the first fully autonomous vessels to cross the Atlantic Ocean. During the voyage, the vessel’s navigation system successfully interpreted multiple S-100 data sets provided by the UKHO, including S-102, to understand its surroundings and navigate from Plymouth, England, to Halifax, Nova Scotia.

Shaping the future of navigation

The benefits of S-102 for maritime navigation are becoming increasingly clear. Trials are demonstrating how S-102 bathymetric data, together with other S-100 data layers, can provide mariners with a more complete and dynamic picture of the marine environment. Alongside its ability to support autonomous systems, these capabilities highlight the promise of S-102 to become a key component of next-generation navigation systems.

Type-approved S-100 ECDIS are currently expected to become commercially available around 2028, with exact timelines dependent on further standards development, testing and certification processes. These systems will also be “dual-fuel,” meaning they will be able to display and use both S-100 and existing S-57 data.

Ahead of this, further S-100 trials are planned around the world, bringing together hydrographic offices, ECDIS manufacturers and end users to ensure S-100 standards meet operational needs and support safe navigation. Insights from previous trials are already being shared across the maritime community, with hydrographic offices, including the UKHO, also making S-100 data sets publicly available so users can explore and interact with the data.

As the transition to S-100 continues, maritime stakeholders have a unique opportunity to help shape how S-102 and other S-100 data layers are implemented and how their benefits can be realized in practice. By engaging with industry partners and keeping informed on S-100 developments, organizations can contribute valuable feedback while building their own understanding of S-102 and how it could support their operations.