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> coming to and/or operating at periscope depth is dangerous Silly question: how do you identify a target? Sound only? It seems like you would want something

by dockd 5y ago

> coming to and/or operating at periscope depth is dangerous Silly question: how do you identify a target? Sound only? It seems like you would want something visual.

_3u10 5y ago
Each sub / surface vessel gives off a unique acoustic signature. My understanding is that US subs don’t travel in packs, so anything they detect is generally the enemy, and especially so if it’s submerged, unless they are escorting a carrier.
jedc 5y ago
Yep, just sound. And you don't even know range, you only know how strong sound is on a particular bearing. The Navy trains to do a series of maneuvers that helps you understand the range to the ships you do hear, and positions the sub most safely to come to periscope depth. And then while you're coming to periscope depth you're looking out to see if there are any indications you've screwed up. But yeah, there's nothing visual available when you're under the water.
HarryHirsch 5y ago
Sound only. Submarine navies go to great lengths to collect sound samples of potential opponents.
- sas224dbm 5y ago
  I worked on Target Motion Analysis (TMA) software that was live on S&T class UK submarines in the 90s. There were only a few types of data that were highly classified and which we never saw, Electronic Surveillance Measures (ESM) databases were an example. Emitter characteristics could pretty much allow a good SONOP (Jonesy!) to be able to identify specific instances of a class of boat. Fun stuff.
dylan604 5y ago
Sonar identification is incredibly accurate (with computer assitance). We've been dragging "mics" through the ocean for a long time. They can identify the exact ship by noises coming from the engine(s), the propellers, etc. They can count the rpm of the props of that ship and determine it's speed. They can tell if it is approaching, going away, etc. During sea trials of a new boat, they have it do passes specifically for sonar to listen to it. Partly so they can learn its sound signature, but also to see if they can hear annomalies during construction. They've found toolboxes left inside a double hull by the builders. They do have visuals with the waterfall displays and what not. Last I looked into sonar operations was in the early 90s, so not sure what the kids are using now. They can do all of this without making a sound to allow someone else to know they are there.

by dockd 5y ago

> coming to and/or operating at periscope depth is dangerous Silly question: how do you identify a target? Sound only? It seems like you would want something visual.

_3u10 5y ago

Each sub / surface vessel gives off a unique acoustic signature. My understanding is that US subs don’t travel in packs, so anything they detect is generally the enemy, and especially so if it’s submerged, unless they are escorting a carrier.

jedc 5y ago

Yep, just sound. And you don't even know range, you only know how strong sound is on a particular bearing. The Navy trains to do a series of maneuvers that helps you understand the range to the ships you do hear, and positions the sub most safely to come to periscope depth. And then while you're coming to periscope depth you're looking out to see if there are any indications you've screwed up. But yeah, there's nothing visual available when you're under the water.

HarryHirsch 5y ago

Sound only. Submarine navies go to great lengths to collect sound samples of potential opponents.

sas224dbm 5y ago
I worked on Target Motion Analysis (TMA) software that was live on S&T class UK submarines in the 90s. There were only a few types of data that were highly classified and which we never saw, Electronic Surveillance Measures (ESM) databases were an example. Emitter characteristics could pretty much allow a good SONOP (Jonesy!) to be able to identify specific instances of a class of boat. Fun stuff.

dylan604 5y ago

Sonar identification is incredibly accurate (with computer assitance). We've been dragging "mics" through the ocean for a long time. They can identify the exact ship by noises coming from the engine(s), the propellers, etc. They can count the rpm of the props of that ship and determine it's speed. They can tell if it is approaching, going away, etc. During sea trials of a new boat, they have it do passes specifically for sonar to listen to it. Partly so they can learn its sound signature, but also to see if they can hear annomalies during construction. They've found toolboxes left inside a double hull by the builders. They do have visuals with the waterfall displays and what not. Last I looked into sonar operations was in the early 90s, so not sure what the kids are using now. They can do all of this without making a sound to allow someone else to know they are there.