Operational Guide · Registers & Logbooks

# VDES and NAVDAT: the Next Generation of Digital Maritime Communications

The VHF channel we knew as voice-only becomes a data channel too: two new systems enter the SOLAS framework for ship-shore digital information exchange and safety broadcast transmission.

VDES NAVDAT NCSR digital communications

## Operational Explanation

The NCSR (Navigation, Communications and Search and Rescue) sub-committee finalised, at its NCSR 12 (May 2025) and NCSR 13 (June 2026) sessions, the technical framework for two new maritime digital communication systems. VDES (VHF Data Exchange System) introduces digital data exchange over the VHF channel, on a voluntary basis, through amendments to SOLAS Chapter V: adopted at MSC 111 (May 2026), with entry into force expected from 1° January 2028. NAVDAT is instead a shore-to-ship digital broadcast transmission system for maritime safety and search-and-rescue information, with the manual and technical roadmap being finalised.

In parallel, IMO has established that maritime safety information (MSI) will have to be disseminated through all recognised mobile satellite services (RMSS) in operation by 31° December 2026, with amendments to SOLAS Regulations IV/5, V/4 and V/5. NCSR 13 also finalised the MSC circular on the transition scheme for digital VHF voice communications, with a roadmap that keeps the existing GMDSS safety channels in place during the introduction of digital capability.

## Regulatory Reference

SOLAS Chapter V (NCSR 12/13 amendments, adopted at MSC 111, May 2026): voluntary introduction of VDES, in force from 1° January 2028. SOLAS Regulations IV/5, V/4, V/5: mandatory dissemination of MSI through all recognised RMSS in operation by 31° December 2026. NAVDAT: manual and roadmap being finalised, approval expected at MSC 112 (December 2026).

## Scope of Application

Every ship subject to SOLAS Chapter V/IV; voluntary application of VDES from 2028; mandatory MSI reception through all recognised operational RMSS by the end of 2026.

## Procedure / How to Complete It

1. Monitor publication of the consolidated text of the SOLAS Chapter V amendments on VDES, ahead of voluntary entry into force from 2028.
2. Verify, by 31 December 2026, that on-board GMDSS equipment is able to receive MSI from all recognised operational RMSS, not just the one historically installed.
3. Follow the transition scheme for digital VHF voice communications published by NCSR 13, maintaining full familiarity with the existing GMDSS safety channels during the digital introduction phase.
4. Train officers of the watch on the distinction between existing systems (traditional GMDSS) and new digital capabilities (VDES, NAVDAT) as soon as they become commercially available.
5. Coordinate with the on-board equipment supplier to understand the timeline for commercial availability of the new VDES/NAVDAT capabilities.

## Practical Example

Example: a Company verifies, ahead of the 31 December 2026 deadline, that its fleet's satellite equipment is configured to receive maritime safety information from all recognised operational RMSS, not only from the long-standing contracted provider.

## Real Cases

The transition from a voice-only VHF channel to one that also carries data (VDES) responds to a growing need for efficient exchange of information between ship and shore — weather data, route information, safety updates — without having to rely exclusively on voice communications or costly satellite channels for every type of information exchange, while keeping the primary safety function of traditional GMDSS channels fully intact throughout the transition phase.

## Common Mistakes Mistake Library

Mistake | Consequence | How to avoid it
--- | --- | ---
On-board satellite equipment verified as compatible only with the historically contracted RMSS provider, without checking compatibility with all recognised operational services | Risk of not receiving critical MSI transmitted through an RMSS provider other than the usual one | Verify, ahead of the 2026 deadline, equipment compatibility with all recognised operational RMSS providers, not just the contracted one
Introduction of new digital capabilities (VDES, NAVDAT) confused with a replacement of the existing GMDSS safety channels | Mistaken underestimation of the importance of maintaining full familiarity with traditional safety channels during the transition | Treat VDES and NAVDAT as additional capabilities, not substitutes for the existing GMDSS safety channels, until the transition is complete

## PSC Observations

PSC verification of GMDSS systems remains focused on the requirements currently in force; as the 2026-2028 deadlines approach, an extension of verification to multi-RMSS MSI reception compatibility, and subsequently to the new VDES capabilities, can be expected.

## Operational Tips

- Do not wait for the 31 December 2026 deadline to verify the multi-RMSS compatibility of on-board satellite equipment.
- Follow publication of the consolidated SOLAS text on VDES and finalisation of the NAVDAT manual (expected at MSC 112, December 2026) to plan fleet upgrades ahead of time.
- Do not treat the new digital capabilities as substitutes for the existing GMDSS safety channels: they are additional capabilities during a long-term transition phase.

## Checklist

- Multi-RMSS compatibility of satellite equipment verified before 31 December 2026
- Consolidated SOLAS Chapter V text on VDES monitored ahead of the 2028 entry into force
- Finalisation of the NAVDAT manual monitored (expected MSC 112, December 2026)
- Officers of the watch trained on the distinction between existing GMDSS systems and new digital capabilities
- Traditional GMDSS safety channels kept fully operational during the transition

## FAQ

What is VDES?
The VHF Data Exchange System, a system introducing digital data exchange over the VHF channel, adopted through amendments to SOLAS Chapter V at MSC 111 (May 2026), on a voluntary basis, with entry into force from 1 January 2028.
What is NAVDAT and what stage of development is it at?
A shore-to-ship digital broadcast transmission system for maritime safety and search-and-rescue information; the technical manual and roadmap are being finalised, with approval expected at MSC 112 (December 2026).
What changes by 31 December 2026 regarding reception of maritime safety information?
MSI will have to be disseminated through all recognised mobile satellite services (RMSS) in operation, not only through the service historically installed on board, under amendments to SOLAS Regulations IV/5, V/4 and V/5.
🎬 Additional photos, videos and interactive diagrams for this topic will be available in a future version of the platform.

## Related Topics

GMDSS (Global Maritime Distress and Safety System)Electronic Navigation and GNSS Resilience

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