Submarine Rings

[poozinsc]

Newbie question -- What do the thick green rings surrounding a submarine indicate?

[Baloogan]

convergence zones

[Baloogan]

Range of the passive sonar, due to the way sound waves bend in the deep ocean.

[Baloogan]

Basically, you can hear good out to the first ring
any area that is shaded you can't hear at all
you can hear really loud things (aircraft carriers, tankers) in the regions between the rings if you go slowly.

[poozinsc]

Thank you -- helps a lot