Heard it alot in those submarine movies, what does it mean?
From the inside of the sub, would you acctually hear: Ping… ping… ping?
Ain’t it supposed to be the PING of the magical radar? Maybe the other subs PINGing, because, you know, radar’s really loud and echoes when it hits the metal.
pinging? My god, there were trolls and spammers even back then?
Based on a thorough grounding in Tom Clancy books… there are two types of sonar: active and passive. Passive sonar basically involves highly sensitive microphones, highly sophisticated digital analysis software, and highly skilled technicians. They can pinpoint the location and bearing of objects - such as other submarines - making noise underwater without revealing their own position.
Active sonar is just as you suggest: a blast of sonic energy that comes from the tracker, and reflects off the trackee to provide precise location information. As I understand it, it can be heard instead the target submarine.
- Rick
Not radar, sonar. Yes, it is a sound somewhat similar to the one reproduced in the movies.
There are two general ways (outside new, supersecret stuff) to identify the direction and distance to another object when one is trying to “see” through water.
The first is simply listening. This is passive. Special microphones are used to try to identify the direction from which a sound may be coming. The sound can be caused by the propellors/screws of the other ship, the sound of the hull passing through water, or the sound of the engines or other machinery running on the other ship. The passive method is good, because your ship is not doing anything to call attention to itself (aside from running its machinery to turn its screw(s) to pass through the water–all of which can be minimized, or eliminated if one shuts down all the systems).
It has a disadvantage that it relies on the training and experience of the technician using the sound equipment to estimate the distance from the source of the sounds to one’s own ship–and a lot of things can interfere with those educated guesses.
When sonar uses pinging, it sends out a sound that travels to other objects and bounces off them, returning to the receiver portion of the sonar. Since the spped of sound in water is known, the time that elapses from the ping to its “return” tells the operator exactly how far away the other ship is. Since sound will be reflected differently by different shapes and sizes, it can also be used (with some hedging) to identify the type of ship that has been pinged.
The disadvantage is that the other ship can hear the pinging quite clearly, thus giving away one’s position to that ship.
This MB has a whole bunch of squids posting to it, so I’m going to refrain from posting anything very technical to avoid serious corrections.
In Did whispering on submarines really make a difference? the guys with some experience did a fairly exhaustive treatment of the subject.
Damn, damn, damn!!!
I actually knew this answer, outside of the lame example I’m about to give.
tombdebb nailed it.
If you’re a fan of submarine movies, you need to check out the movie “Red October”.
Not only is it a good movie, but it actually portrays a semi-real submarine ‘ping’, from the perspective of both the inside and outside of a submarine.
Or at least that’s what I’ve heard, I’ve never been in a sub.
I will add that sonar waves are often deviated by the difference in temperatures between layers of water. In effect this means there are “blind” zones around a ship where sonar echos will not be received. Subs, can effectively hide in such layers of water and not be detected by the ship’s sonar. To counteract this, ships will tow underwater a sonar drone which, being at the right depth, can detect the subs hiding in the blind zone.
Lots of good info above.
It should be noted that subs will almost never use active sonar, because as has been mentioned, it’s like running down a street yelling “Here I am!, Here I am!”.
It was mentioned above that passive sonar relies mainly on skilled techs. While true, the system software also does a respectable job of trying to identify noises.
Also, there was a question about whether or not you can hear the actual ping. My old office was across the river from a submarine tender that supported a squadron. They would occasionally do pierside testing of their active sonar and from my office I could hear it. It wasn’t loud like an air-horn or anything, but it was more felt than heard, kinda came through your skeleton.
Sub navigation is actually an amazing feat. You’re blind (no windows on most subs). You’re hearing is limited to passive sonar, which although good, does have it’s limitations (i.e. Japanese fishing trawlers). Thankfully you have excellent navigation tools, (GPS, amazingly accurate gyroscopic systems, and the like), coupled with some detailed maps and charts.
From what I remember, the noise is quite loud if it is your sub or ship that’s doing the “pinging” but, at least in a surface ship, very hard to hear other ships nearby who may also be pinging. (except, of course, if you are monitoring sonar).
A couple other interesting (at least to me) notes. There are a lot of reasons not to use active sonar – not only does it announce your presence, but it is counter detectable much farther away than it can actually detect the target. It’s kind of like using a flashlight in the woods to look for someone. Active sonar also makes trying to use passive sonar extremely difficult if not impossible because of the excessive background noise it generates.
From my experience (5 years of aviation anti-submarine warfare), subs almost never use active sonar because their passive systems are so good and stealth is their best weapon, but surface and aviation assets looking for subs often use active. Generally, once the target sub’s position has been generally located, aircraft will switch to active to get a more accurate solution to put a weapon in the water.
Submarine wavs amongst others at http://www.specialoperations.com/Multimedia/sounds.html
Found an amazing site a couple of days ago for people building their own sub’s. Most of them were small one person designs, but a guy was building one which could take a crew of 6 on a week long run. Will post the link as soon as I dig it out of my history.
milo
Sub Sailor, checking in.
In general, active sonar on submarines is used for two purposes:
- To firm-up a firing solution when you’re in a hurry.
- To harrass someone you’re not planning on actually shooting.
Passive sonar is very good, and by using triangulation, a good firing solution can be determined in a reasonable amount of time. Some of the triangulation can be done by sensors attatched directly to the hull, but using a towed array gives a much better estimate. Ideally, when there’s plenty of time, a boat will take several bearings to get a good solution before shooting. In any circumstance, it’s a rare thing, indeed, to fire a straight “bearing only” shot. Modern torpedoes are very effective hunters in their own right, and all the boat has to do is get the fish close, either by carefull calculation, or by guiding it in via wire. Once the fish is in the right area, it will execute it’s own attack, using both passive and active sonar. Once the wire is cut, a torpedo is an autonomous killing machine.
Avoiding a torpedo is both science and art, and an accurate discussion of the methods would take pages. Simply put, you can dodge, spoof (decoy), or hide. Likely, all of the above.
Active sonar is, as has been said, a great way of announcing your presence to the whole world, which is anathema to the Silent Service. In certain circumstances, it’s still very necessary. Some of those include: When firing a counter-shot (someone just bounced you, and you don’t know where they are), certain (rare!) restricted manuevering scenarios , and harrassing someone you could have shot, but aren’t planning on actually shooting (sorta like sneaking up on someone and yelling “BANG”). That’s not the whole list, but is a sample.
One other note: Active Sonar doesn’t always go “Ping”. US sonar, for instance, frequently sounds like a short warbling whistle. Russian sonar, at least from my limited contact with it, can sound like a series of guitar strings being plucked. Other variation of pulses are available. Active sonar can be d*mned loud, to the point of killing fish, and even people, if they’re in the water nearby when the sonar is activated. Also, newer technologies exist that can allow a boat to go “active” while making it very hard to pin-point the source of the pulse. The world knows you’re there, but not where “there” is.
Now that I’m wondering, and it is along the same lines as the O.P., does the computer ‘ping’ that we know of come from the submarine ‘ping’.
It’s kind of the same thing, in a way. Is there a direct connection there?
Yep, that’s where we got it from. Check out: http://www.tuxedo.org/~esr/jargon/html/entry/ping.html