30-kilometer ring around tugboat contact?
 

Observed a tugboat just off the coast of the Netherlands. When I clicked on the contact on the Navigation map, it showed a broken circle around the contact with a 30-kilometer radius.

What would be the reason for a 30-kilometer ring around this type of contact? Previous discussion about rings around contacts indicated ASDIC, visual & hyrophone distances but I do not understand why there would be a 30-kilometer ring around a tugboat.

Any ideas? By the way, I'm running the new GWX 2.0 which GREAT, love it.

Just guessing here...visual spotting range maybe? :hmm:

I am also guessing: Maybe it's an armed tug?

I have seen similar things with armed trawlers in the channel. I should have thought it would be 16km radius with 30km diametre with the 16km atmosphere activated.

I'm not using the 16k mod. Definitly was a 30km radius and I was well within it. Most likely 5 to 6 km away when I spotted the tugboat. 30km is too great for visual, possible it was ring for hydrophone?