Correct, "array depth": Subsim DW review:

http://www.subsim.com/ssr/dangerous_..._PassiveBB.JPG

In RA, many submarines have DTA (Depth of Towed Array) information in broadband mode:

(SSN-21 Seawolf + SSN-23 Jimmy Carter + Virginia + Trafalgar + Trenchant
Type 212 + Type 212A + Collins + Rubis + Amethyste + Suffren)

http://ra-dwx.narod.ru/F2_3.jpg


(Akula-I + Akula-I Impoved + Akula-II + Akula-II Impoved
Oscar-II + Delta-IV + Typhoon 941U + Borey)

http://ra-dwx.narod.ru/F2_1.jpg

http://ra-dwx.narod.ru/F2_2.jpg

Oh cool. They modded that into the interface.

Playing DW since 2005 (on and off, of course).
Never, ever noticed/thought about what DTA is...

This is what amazed me about this sim.
You can learn new things about it after hundreds of hours of playing.