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It seems like it is common for military vessels to turn off their AIS regularly, presumably to hide their movements. The USS Fitzgerald had its AIS turned off
by lgvln 4y ago
It seems like it is common for military vessels to turn off their AIS regularly, presumably to hide their movements.
The USS Fitzgerald had its AIS turned off right outside of Tokyo, another busy shipping lane, when it collided with a container ship. [0]
Interestingly, the corresponding Wikipedia page of the collision is omits the AIS factor completely. [1]
[0] https://maritime-executive.com/article/fitzgerald-made-20-knots-through-traffic-without-ais https://maritime-executive.com/article/fitzgerald-made-20-kn...
[1] https://en.m.wikipedia.org/wiki/USS_Fitzgerald_and_MV_ACX_Crystal_collision https://en.m.wikipedia.org/wiki/USS_Fitzgerald_and_MV_ACX_Cr...
- bergie 4y agoYep. Military, coast guard are both often without AIS. Actually, I think the only times I’ve seen military vessels with AIS on has been during some courtesy visits to other countries. The AIS static data is often not super useful (I think I saw a carrier reporting itself as something like “Uswarship03”). Fishing boats reputedly run without AIS as well to hide their (potentially illegal) activities. Then there are obviously pleasure craft that are not required to have AIS. But at least in the southern Baltic, most seem to carry a transponder.
- vintermann 4y agoThey can also spoof it, as the article suggests. Since it's rather suspicious when you suddenly turn off the transponder, I would certainly assume the sabotaging ship could have had a "cover story" in a nearby position.