From: Upstate New York USA
One thing about towed arrays....When you drag them on a very long line and are moving slowly, they will drop below the level of your ship, and thus are able to "see" past the towing vessel. I'm not any expert by any means, so I don't know just how effective the forward hearing is, but at least there is some capability there.
As for the multiple towed arrays, US subs, LAs and the Seawolf at least, do have more than one towed array. Why they mounted two different models I don't know. Cost perhaps? The TB-16 is an older model than the TB-29, and may be a cheaper "backup." A sub guy could probably tell better. You can see this modeled in sub simulators like 688i or Dangerous Waters, which have both models available to the player.
"It's all according to how your boogaloo situation stands, you understand."
Formerly known as Colonel Mustard, before I got Slitherine Syndrome.