S-100 explained: what the new hydrographic data standard means for maritime navigation

S-100 will bring hydrographic data to life

The ability to provide time-varying or near real-time updates on dynamic ocean conditions will boost the safety of maritime navigation, particularly in coastal waters and ports.

With the roll-out of the International Hydrographic Organization’s (IHO) new S-100 data standard, mariners will benefit from greater accuracy and functionality than is possible with existing S-57 static electronic navigational charts and overlays. 

S-100 allows for the automatic integration of more diverse hydrographic data elements, including for example, Tidetech’s oceanographic data, which is centred on dynamic environmental parameters, specifically water levels (S-104) and surface currents (S-111). 

This functionality will enrich navigational support systems beyond current static bathymetric data based on five or 10 metre contour lines and static depths reduced to chart datum (for example approximately the level of lowest astronomical tide).

“The S-100 standard is a framework designed to make maritime data richer, smarter, and more geographically aligned,” said Penny Haire, Tidetech’s CEO.

“It’s a big change, but it’s also a logical progression aimed at enhancing situational awareness and decision-making tools.”

S-100 will make it easier for electronic navigational chart displays and information systems (ECDIS) and portable pilot unit systems (PPUs) to provide a consistent, accurate picture of passage conditions for everyone on the bridge to work from, what the military call a common operating picture. Sub-ECDIS commercial mariners will also benefit from more timely and accurate navigational information in non-ECDIS applications.

Ports will be able to increase safety within their waters by making use of accurate bathymetric data in their traffic management systems, which brings the added potential for optimising tug and fender operations. Greater accuracy and resolution in tidal heights with S-104 will potentially increase safety margins vessels and ports can use.

More accurate under-keel clearance (UKC) data will enable ship operators to fine tune cargo carrying capacity and berth planning to improve profitability. Their voyage planning systems will be able to factor in prevailing conditions to schedule port entry and reduce emissions — benefits available to both cargo shipping companies and offshore energy operators. 

Navies and coast guards will also be able to optimise their voyage plans, particularly for shallow-draft and amphibious craft operations.

Future potential

The functionality made possible by S-100 is itself dynamic. The standard is built around product specifications, feature catalogues and portrayal catalogues that can evolve over time.

“One of the strengths of S-100 is that it’s a flexible data framework rather than a single, fixed product,” said Christopher Jones, the UK Hydrographic Office’s Tides Technical Lead. 

“That means new capabilities do not always require the whole system to be reinvented. As user needs change, or as technology improves, individual product specifications can be updated, refined, or added. It gives the industry a way to incorporate richer datasets, improved portrayal, and new use cases within a recognised structure, rather than starting again with each innovation,” Jones said.

“From a future-looking perspective, S-100 gives maritime navigation a framework better suited to continuous improvement. That is especially important as hydrographic offices, OEMs and service providers learn more through implementation and operational trials.” 

Testing underway

Trials are already being conducted onboard ships and using simulators in the UK, France, Canada, and Australia. The trials bring together hydrographic offices, system OEMs, operators, ports, and specialist data providers. 

“This is important because successful S-100 implementation depends on interoperability across the whole chain, not just on one organisation producing one dataset,” Jones said.

Tidetech’s high-resolution English Channel and Solent models are active in several S-100 evaluations, including UKHO and French hydrographic office (Shom) trials that have been on-going since August 2025. The hydrographic offices are working with partners including ECDIS OEM Raymarine and ship operator DFDS to deploy S-100-enabled ECDIS onboard the Stena Vinga ferry, navigating initially from Portsmouth to Jersey then extending across the English Channel to Saint-Malo — a route chosen for its strong currents and tidal constraints.

“The trials have moved the conversation from theory into operational reality,” Jones said. 

They are helping identify where the more accurate data shows the strongest operational value. 

“In the case of the Stena Vinga route, the tidal and cross-border nature of the operating environment makes it a useful test bed for understanding how layers such as S-104 and S-111 may support bridge decision-making in practice. That is exactly the kind of evidence the industry needs as it prepares for broader rollout,” he said.

Tidetech’s ability to stitch together high-quality bathymetry from multiple sources (including UKHO) is vital because modelling dynamic water levels and currents depends on understanding the seabed accurately, Jones said.

“That is one reason why interoperable S-100 layers matter — the value comes from how the datasets work together rather than one in isolation.”

Managing expectations

The full potential of S-100 will, like S-57, be dependent on the quality of the data collected during hydrographic surveys. 

Different hydrographic offices are adopting different strategies in their S-100 rollout.

“Some will repackage existing data as they deal with the time and expense required to enhance their offerings,” Haire said.

Tidetech is working with partners to demonstrate the value of high-quality data and models, but ultimately, implementation will be patchy due to the differing capabilities of hydrographic offices around the world. It could take 20 years before everyone globally will have access to an enhanced and unified navigational system.

“It’s therefore important to remember that just because something is represented digitally, it doesn’t necessarily follow that it’s going to be accurate. For ECDIS users, the roll out of more accurate data will depend on the quality of survey data available for a specific location,” said Haire.

Survey in this context means bathymetric survey, but for the broader aims of S-100, additional repeated measurements of water levels and currents will be needed to validate the models which will ultimately be delivering the 4D (spatial-time) data.

This means the benefits will be felt at different rates around the world.

Preparing for change

Major milestones have been set for the roll-out of S-100. The first type approved S-100 ECDIS systems are anticipated in 2028, and there will be a transition period until 1 January 2029 when all new or retrofitted ECDIS systems must be S-100 capable. 

S-57 will not be retired immediately. A period of ‘dual-fuel’ S-57 and S-100 operation is expected, with no specific date set yet to sunset the old standard.