[C-Wolf]

They're called transients for a reason. Unless the coffee's potent, everyone's on the ball, and the primary operator is listening to that particular bearing, they're possible to miss, unless close aboard and very loud.

There's another launch mode that is very quiet: swim-out, as opposed to being impulse out of the tube by water. It also depends greatly on the relative bearing the launch point originates. A broadband noise in the baffles can be very hard to detect. High-speed screws, with their very loud dB level propagating in all directions with an accompanying active torpedo search sonar is a different story.

CCC