Decision Simulator

ANL Wyong — The Target That Wasn't Stopped

King Arthur
General cargo vessel · Strait of Gibraltar, 4nm SE of Europa Point · 4 August 2018
Source: MAIB Report 7/2020

3Decision Points 3Possible Outcomes —Avg. Play Time

The Situation

You're the OOW on watch aboard a general cargo vessel in fog in the Strait of Gibraltar. AIS shows a container ship ahead of you, with a speed-over-ground reading close to zero — it looks stopped.

The Lesson

AIS data must always be cross-checked against radar in fog and restricted visibility. It's supplementary information, not a primary collision-avoidance solution on its own.

Human Element

AIS had become the primary tool for assessing the target's motion, but it was misread — and once the OOW's attention shifted to an incoming VHF call at the critical moment, the window to correct that misread picture and take avoiding action closed.

Try the First Decision

The AIS speed-over-ground reading for the target ahead looks close to zero. You could take that reading at face value, or cross-check it against the radar picture before deciding anything.

A. Cross-check the AIS reading against the radar plot before concluding the target is stopped

B. Accept the AIS reading at face value — it shows stopped, so there's no need to double-check

This is a preview — the full scenario branches from here based on what you choose, with real consequences and a debrief at the end.

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