# Navy subs: no sonar when divers present? (Slang glossary) **URL:** \ **Category:** Factual Questions\ **Created:** [August 29, 2016, 8:20pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429 "2016-08-29T20:20:57Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [August 29, 2016, 8:20pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/1 "2016-08-29T20:20:57Z")
Found this is a glossary of submariners’ slang. It’s not one of the slang terms to my eyes, oddly, so I don’t know why it’s listed. Maybe “1MC” means something special (I don’t know what it means slang or not). Diver’s 1MC Announcement - “There are divers over the side, do not rotate screws, cycle rudders, take suction from or discharge to the sea, blow flood or vent any tanks, or operate any underwater equipment or activate sonar. There are divers over the side.” Also, “over the side” sounds weird to me, but what the hey. Also, do these phrases ring bells for the local bubbleheads? > **[Log into Facebook](https://www.facebook.com/notes/randy-pace/submarine-slang-terms-and-phrases/10151136788588486)** > > Log into Facebook to start sharing and connecting with your friends, family, and people you know. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [August 29, 2016, 8:22pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/2 "2016-08-29T20:22:51Z")
1MC is the public address system on the sub - making an announcement over the 1MC means everybody gets the message (which is what you want for a safety announcement, of course) [1 Main Circuit - Wikipedia](https://en.wikipedia.org/wiki/1MC) ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [August 29, 2016, 8:26pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/3 "2016-08-29T20:26:42Z")
OP ETA: I guess I didn’t add, to be clear: all the other activities in the operation, care, and feeding of the sub as being hazardous to a diver I can see. But with the sonar: is some sort of device deployed? Otherwise I have this image of some colossally loud sound impinging on the diver with harmful effects, and that sounds unlikely… ---
**Author:** ![muldoonthief](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muldoonthief/32/3188_2.png) [@muldoonthief](https://boards.straightdope.com/u/muldoonthief)\ **Post date:** [August 29, 2016, 8:47pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/4 "2016-08-29T20:47:13Z")
> [@Leo\_Bloom](#): > > OP ETA: I guess I didn’t add, to be clear: all the other activities in the operation, care, and feeding of the sub as being hazardous to a diver I can see. But with the sonar: is some sort of device deployed? > > Otherwise I have this image of some colossally loud sound impinging on the diver with harmful effects, and that sounds unlikely… No, that’s exactly it. Active sonar is very loud (over 230 dB) when generated, and water transmits sound much better than air. So a sonar ping a few feet away could easily deafen a diver. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [August 29, 2016, 9:20pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/5 "2016-08-29T21:20:33Z")
It seems like the OP’s main question has been addressed; I don’t really have anything to add. > [@Leo\_Bloom](#): > > …Also, “over the side” sounds weird to me, but what the hey. The divers enter the water by going over the side of the surfaced submarine. It implies that they are in the water in close proximity to the sub. > [@Leo\_Bloom](#): > > Also, do these phrases ring bells for the local bubbleheads? > > [Redirecting...](https://www.facebook.com/notes/randy-pace/submarine-slang-terms-and-phrases/10151136788588486) Sure. 😉 Did you have a question about any particular phrase? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 30, 2016, 12:38am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/6 "2016-08-30T00:38:16Z")
> [@muldoonthief](#): > > No, that’s exactly it. Active sonar is very loud (over 230 dB) when generated, and water transmits sound much better than air. So a sonar ping a few feet away could easily deafen a diver. As you say. Various green groups have been / still are up in arms that active sonar is essentially torturing the whales and other sea creatures. A quick Google for [sonar whale harm] will bring up a variety of sites and cites of varying believability. But you’ll also find news articles about various real Federal court cases that went against the real US Navy and now limit their use of some active sonar devices. ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [August 30, 2016, 12:40am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/7 "2016-08-30T00:40:28Z")
> [@muldoonthief](#): > > No, that’s exactly it. Active sonar is very loud (over 230 dB) when generated, and water transmits sound much better than air. So a sonar ping a few feet away could easily deafen a diver. At that distance and level it would probably kill him outright. ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [August 30, 2016, 3:25am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/8 "2016-08-30T03:25:29Z")
> [@muldoonthief](#): > > No, that’s exactly it. Active sonar is very loud (over 230 dB) when generated, and water transmits sound much better than air. So a sonar ping a few feet away could easily deafen a diver. If there was a diver in the water when an active sonar was fired (though I am not sure about a submarine’s sonar) the intensity would be enough to kill the diver. A strong bi-static sonar (see the 230 dB) is quite loud enough to kill at close range. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [August 30, 2016, 3:54am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/9 "2016-08-30T03:54:15Z")
Men working aloft Do not rotate, radiate, or otherwise energize. Men working aloft. That is all. ---
**Author:** ![ThisSpaceForRent](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thisspaceforrent/32/345_2.png) [@ThisSpaceForRent](https://boards.straightdope.com/u/ThisSpaceForRent)\ **Post date:** [August 30, 2016, 4:04am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/10 "2016-08-30T04:04:47Z")
There are two modes of SONAR operation…Passive and Active. In passive mode they (we) are simply listening…for other ships screws (propellers), torpedos and anything else with a sound pattern. In Active mode the SONAR is PINGING, that is putting out an audible (very fucking loud) PING, thusly measuring the reflection time back to the vessel. Both ships and subs (boats) use both modes of SONAR. My rack for 2 years was on the outer hull wall two levels below the water line, many a night I was lulled to sleep with active pinging. Ships use the same 1MC announcement. tsfr FTG3 USS Virginia CGN 38 (ship decommed and cut up for scrap) ---
**Author:** ![ThisSpaceForRent](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thisspaceforrent/32/345_2.png) [@ThisSpaceForRent](https://boards.straightdope.com/u/ThisSpaceForRent)\ **Post date:** [August 30, 2016, 4:11am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/11 "2016-08-30T04:11:58Z")
> [@UncleRojelio](#): > > Men working aloft > Do not rotate, radiate, or otherwise energize. > Men working aloft. > That is all. LOL, being an FTG (RADAR tech) I was typically the guy “working aloft” “Flight Quarters, Flight Quarters”…damn, the smoking lamp is out! ---
**Author:** ![chorpler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chorpler/32/2888_2.png) [@chorpler](https://boards.straightdope.com/u/chorpler)\ **Post date:** [August 30, 2016, 8:18am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/12 "2016-08-30T08:18:42Z")
How does a submarine generate such a loud sound? I would guess that it would be generated from some kind of speaker using electrical power to convert an electronic signal into sound, and not, say, a big bell that they clang back and forth underwater, but I have no idea if my guess is at all accurate. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [August 30, 2016, 9:44am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/13 "2016-08-30T09:44:42Z")
> [@chorpler](#): > > How does a submarine generate such a loud sound? I would guess that it would be generated from some kind of speaker using electrical power to convert an electronic signal into sound, and not, say, a big bell that they clang back and forth underwater, but I have no idea if my guess is at all accurate. They use mushrooms. I am [not](https://en.wikipedia.org/wiki/Tonpilz) joking. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [August 30, 2016, 11:57am UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/14 "2016-08-30T11:57:43Z")
Give me a ping Vasili, one ping only. ---
**Author:** ![Ex\_Bubblehead](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ex_bubblehead/32/3397_2.png) [@Ex\_Bubblehead](https://boards.straightdope.com/u/Ex_Bubblehead)\ **Post date:** [August 30, 2016, 12:56pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/15 "2016-08-30T12:56:32Z")
> [@chorpler](#): > > How does a submarine generate such a loud sound? I would guess that it would be generated from some kind of speaker using electrical power to convert an electronic signal into sound, and not, say, a big bell that they clang back and forth underwater, but I have no idea if my guess is at all accurate. The BQQ-5 (what I worked on back when) could put 196KW of acoustic energy into the water. But, since Submarines rarely, if ever, light off the main suite in active mode (only happened twice in my 6 years, and then only when entering port) the diver warning applies mainly to underwater comms and fathometers, both of which can injure divers close aboard. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [August 30, 2016, 1:22pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/16 "2016-08-30T13:22:35Z")
> [@UncleRojelio](#): > > Men working aloft > Do not rotate, radiate, or otherwise energize. > Men working aloft. > That is all. I worked for a large science/engineering company once (though our branch was rather small). We called in an expert for something or another (or maybe he was just passing through…I forget). Anyway, for his age his health was pretty bad apparently. The story I got was that he and another guy were working on a ship’s radar system. ANOTHER large vessel came into port with their radar working. Well, these guys were basically at the focus of the non radar active array. His shipmate died. He almost did. ---
**Author:** ![racer72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/racer72/32/3075_2.png) [@racer72](https://boards.straightdope.com/u/racer72)\ **Post date:** [August 30, 2016, 3:05pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/17 "2016-08-30T15:05:58Z")
I remember a similar message on the submarine tender I was on anytime divers were in the water, whether working on the ship or a sub. ---
**Author:** ![brad\_d](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@brad\_d](https://boards.straightdope.com/u/brad_d)\ **Post date:** [August 30, 2016, 4:12pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/18 "2016-08-30T16:12:17Z")
Military aircraft with which I’m familiar incorporate a “weight on wheels” sensor that forbids the plane’s radar from emitting when it’s on the ground - because it can be lethal to nearby people. On modern fighters, the minimum safe distance (in the direction of the main lobe) in the hundreds of meters, I seem to recall. > [@billfish678](#): > > I worked for a large science/engineering company once (though our branch was rather small). > > We called in an expert for something or another (or maybe he was just passing through…I forget). > > Anyway, for his age his health was pretty bad apparently. > > The story I got was that he and another guy were working on a ship’s radar system. ANOTHER large vessel came into port with their radar working. Well, these guys were basically at the focus of the non radar active array. > > His shipmate died. He almost did. Sent from my SCH-I435 using Tapatalk ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [August 30, 2016, 5:06pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/19 "2016-08-30T17:06:00Z")
I was peripherally involved with [one of the research papers mentioned on this site](http://www.oceanmammalinst.com/mgpaper.html#documented). ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [September 1, 2016, 1:25pm UTC](https://boards.straightdope.com/t/navy-subs-no-sonar-when-divers-present-slang-glossary/764429/20 "2016-09-01T13:25:07Z")
> [@billfish678](#): > > I worked for a large science/engineering company once (though our branch was rather small). > > We called in an expert for something or another (or maybe he was just passing through…I forget). > > Anyway, for his age his health was pretty bad apparently. > > The story I got was that he and another guy were working on a ship’s radar system. ANOTHER large vessel came into port with their radar working. Well, these guys were basically at the focus of the non radar active array. > > His shipmate died. He almost did. Wow. I can see how that might happen-another example of why some of those stupid rules (which in this case came one accident too late) aren’t so stupid after all.