S-100: The Next Generation of Electronic Charts Is Coming to Australia

If you’re training or working in the near-coastal space, you’ll hear a lot more about S-100 over the next few years. This is a fundamental change to how hydrographic and navigational data is produced, distributed and displayed. And Australia, through the Australian Hydrographic Office (AHO), is right in the middle of this transition.

Let’s break it down in practical terms.

What Is S-100?

S-100 is the Universal Hydrographic Data Model developed by the International Hydrographic Organization (IHO). Think of it as the framework that allows modern digital navigation products to talk to each other properly.

It's built on the ISO 19100 geographic information standards and is designed to eventually replace the ageing S-57 chart standard that underpins today’s Electronic Navigational Charts (ENC). Where S-57 was essentially a single-purpose chart format, S-100 is modular – meaning different layers of navigational information can be added, updated, and displayed dynamically. This is the backbone of modern e-Navigation.

What’s Changing for Mariners?

Under S-100, charts are no longer just 'charts'. Instead, multiple product specifications work together:

S-101 – Electronic Navigational Charts

S-101 is the direct replacement for S-57 ENCs.

Key improvements include:

• Better handling of multiple languages

• Improved symbology (less clutter, less explanatory text)

• Clearer depiction of sectored lights

• Easier identification of ENC updates and changes

For mariners, this means clearer displays and fewer interpretation traps.

S-102 – Bathymetric Surface

S-102 is a high-resolution digital model of the seabed.

Instead of relying solely on spot depths and contours:

• The seabed is displayed as a continuous surface

• Higher accuracy and resolution are possible

• Particularly valuable for restricted waters, port approaches, and berthing

In ECDIS, S-102 can substitute ENC depth information, giving the navigator a far better picture of what’s actually under the keel.

S-104 – Water Level Information

S-104 delivers tidal and water level data as a dynamic dataset.

This allows:

• Real-time or predicted water levels

• Adjustment of depth information based on tide

• More accurate UKC calculations

When combined with S-102, this becomes a game-changer for precision navigation in ports and shallow areas.

S-111 – Surface Currents

S-111 describes surface current speed and direction down to 25 metres.

This supports:

• Safer navigation in constrained waters

• Smarter route planning

• Fuel efficiency and emissions reduction

This isn’t just about safety – it’s about operational efficiency.

S-128 – Knowing What’s Current

S-128 is the Catalogue of Nautical Products.

It becomes the single source of truth for:

• Which charts and publications are current

• What has been updated

• What products are officially in force

For ECDIS and authorities, this removes ambiguity. For mariners, it means less guessing and better confidence.

Traditional navigation systems are on the way our with the introduction of S-100.

Australia’s S-100 Rollout

The AHO is taking a staged, practical approach:

• Port Botany (NSW) will be released as an S-100 sample area by the end of 2025

• Initial datasets will include S-101, S-102, and S-104

• Products will become more widely available from 2026

Early use will be limited:

• Portable Pilot Units (PPUs) are expected to lead adoption

• First type-approved S-100 ECDIS systems are expected by late 2027

• From January 2029, new ship builds will be required by the International Maritime Organisation (IMO) to carry S-100 ECDIS

During the transition, systems will run in 'dual-fuel' mode, supporting both S-57 and S-101 simultaneously. S-57 will only be retired once global S-101 coverage is achieved.

What This Means for Near-Coastal Students

For Coxswains, Masters <24 m and Master <45m:

• You don’t need to panic – paper charts and S-57 aren’t disappearing overnight

• But you do need to understand what S-100 is and why it exists

• Expect future training, assessments and workplace systems to reference these products

This is why we’re already introducing modern navigation concepts into the Small Vessels Manual and training platform – so students aren’t left behind when industry moves forward.

S-100 isn’t just a chart upgrade, it’s a navigation ecosystem. Australia is well positioned, the AHO is actively involved, and the transition will be gradual but inevitable.

Good mariners don’t fear change – they understand it early and adapt safely.

Capt. Cal Callahan

Sail Your Own Course