Subject discussion: detecting a contact's depth

[The Bandit]

Originally Posted by jenrick

Not a submariner, never been in the navy, etc.

With that out of the way, I'd think you could utilize the various hydrophone locations on the subs hull to determined depth. Sound radiates as a wave, so different parts of the wave front will contact the hull at different times (probably miliseconds apart, but enough to matter). For example if the hydrophone on the top of the hull receives a certain sound before one located on the side of the hull, the contact is above the vessel. Add in some fancy math, and you'd have a fair guess of the depth of a contact.

Basically what you're talking about is the principle that the WAA (Wide Aperature Array) on the Seawolf and Virginia class SSNs works off of to passively localize and range sonar contacts. The trouble with actually finding the depth though would be that you'd basically be doing TMA in a 3d field (accounting for vertical movement as well as horizontal) which I imagine would complicate things aboit.

This may just be ignorant oversight on my part, but I don't think that a huge emphasis goes into depth finding other than above or below the layer. Again this is just an assumption but I'm thinking that the detection zone on most of these modern weapons (Mk 48 ect.) would be wide enough that as long as you're in the right neighbor hood (above or below the layer) its not going to matter enough to really take into account.