[Publius6961]

The end of his career. Sad.

The cost of the damage to his boat which must be borne by the taxpayer: sadder.

I was willing to wait for the results of the board of inquiry before criticizing anything.
At this point I need to ask the obvious.

How can a modern submarine, equiped with the latest sonar and gee whiz gadgetry which can spot a sardine at a gazillion yards, fail to register an freakin' underwater mountain?

[7.62 x 51mm]

Agreed. That's a *mystery* which needs to be answered ASAP.

[StoneGiant]

How can a modern submarine, equiped with the latest sonar and gee whiz gadgetry

I would imagine that when running silent there are absolutely no emissions allowed... especially sonar.

While there may be passive listening capabilities that allow sensors to determine images of surrounding terrain, I am unaware of their capabilities and limitations.

[Bottom_Gun]

That's very easy,
1. Active sonar is not used in transit, it gives away your position when used, there by defeating the "stealth" factor of a submarine. only passive sonar is used, which listens to sounds out in the water...and an underwater mount don't make any noise!
2. at those speeds (full bell or higher) sonar is usless, because of flow noise over the hull and array. to hear a concact you have to slow down, or it's right on top of you.

how do I know this? Retired STS1(SS/DV) that's Sonar Tech, Submarines for those not in the know.

[Stonewall Jackson]

Passive sonar, which is the type submarines usually employ to track other vessels and subs, involves listening to the sounds generated by these targets. Active sonar, involves sending out a sound pulse and listening to its return. This allows a vessel or sub to accurately map the area around them, but also pinpoints their own location for anyone else who is out there, a big no-no when you are trying to be sneaky. Additionally, all types of sonar, active and passive, are completely useless when doing a high-speed run like the San Francisco was doing at the time of the crash. They could have run over my cousin's stereo system and not heard a thing.

[demlosers]

How can a modern submarine, equiped with the latest sonar and gee whiz gadgetry which can spot a sardine at a gazillion yards, fail to register an freakin' underwater mountain?

Obviously, the equipment was not in operation during their high speed run. So I suppose the sub thought they knew their location in relation to all the hazards in the area.

I remember reading that the Russians, during the Warsaw pact days, mapped out the Northern Atlantic valleys and sea mounts from the port of Murmansk doing 40 knot or more high speed runs. So they could break out into the Atlantic in time of war. The would not use sonar, they used time/speed plans to do it in the blind.

[PokeyJoe]

Travel at 30 knots underwater and you are deaf, dumb, and BLIND

[MeanWestTexan]

Given the secretive nature of subs, I would think the boat would be running silent with all the sonar, et al, turned off --- being that active sonar is a big "Hello, here I am."

But what do I know? I flew a helicopter in the Army --- I am assuming active sonar is as big a "please kill me, here I am" as active radar.

[pfony1]

Unfornately, those darn passive seamounts make less noise than those active schools of sadines...

As a matter of policy, to avoid detection, US subs do NOT use active sonar to "see" what is front of them.

Still, one could ask whether the use of UHF sonar (which has a very limited range) to "see" a mile or so ahead might become an approved policy in peacetime.