Chart overlay 002


This optional onboard module provides UKC information within a compatible Electronic Charting package on a PPU (Portable Pilot Unit).

DUKC® Chart Overlay is specifically designed for Pilots and Masters. This optional on-board module highlights areas that are unsafe for the ship to navigate through in real-time on compatible Electronic Charting Systems (ECS).

overlay - 2014


The DUKC® Chart Overlay differs from traditional “go” or “no go” displays within ECS because it not only conveys whether it is safe to transit a particular area now, it also predicts, before the transit, whether it is safe when a ship reaches the particular area – a world first. It adds not only the UKC dimension to the electronic chart but also the time dimension.

It is a cutting edge software tool built on proven DUKC® technology which displays UKC information geospatially through a Marine Information Overlay (MIO) on a compatible ECS such as one running on a Portable Pilot Unit (PPU) carried onboard to monitor the passage in real time.

The overlay is based on the latest available high-resolution bathymetry data, prediction of tidal and non-tidal water levels, waves and currents, knowledge of the recorded ship load state (draft, trim, and stability), the pilot’s submitted passage plan (speeds and expected times at waypoints) and predictions of the associated dynamic ship motions (squat, heel, and wave response).

It monitors in real time both horizontal and vertical aspects of the transit.

Key Features:

  • Displays real-time safe and unsafe transit areas (‘go’ or ‘no–go’ areas) at the passage planning stage and during the transit
  • Automatically updates ‘go’ or ‘no-go’ areas based on the latest available met-ocean conditions and actual ship speed and position
  • Predicts the conditions ahead of the time of arrival

Typical questions Chart Overlay can answer:

  • There is a shoal up ahead. Can I safely sail around the shoal without compromising UKC?
  • I am travelling slower than anticipated; can I still safely complete the passage?
  • The weather conditions have deteriorated; how does this impact on safe navigation areas?

Likely Users:

  • Pilots and Masters

Figure 14



‘no go’ areas in high swell conditions (Port Phillip Bay)


Figure 13


‘no go’ areas in low swell conditions (Port Phillip Bay)