INFO NEEDED - Underwater SOUND BOMB device

This interesting device was recently for sale and sold on a auction site and I was so curious as to what it was? I am not sure if it is ordnance related or a experimental explosive device used to study ways of communicating long distances underwater? Anyhow, I would love to learn more about it if any one has any information or insight on it. Thanks so much!


Hi Jason;

Yes, the device is ordnance, normally delivered by aircraft involved in training exercises with submarines. I’ve dropped lots of them. The thing is, submarine skippers don’t appreciate being bombed or torpedoed, so these “sound sources” served to let the sub know it had just been “attacked” by an aircraft during an exercise. The explosion was very small and was harmless to the submarine, but served the purpose of simulating a real bomb or depth charge detonating. The sub was supposed to evaluate the “attack” as being close, medium, distant, etc. But sub officers lie, so all “attacks” were said to be “distant, with no effect.” The aircraft could also use different numbers of charges to communicate to the sub. For example, three closely-spaced charges could mean, “exercise is over, surface.” There was a code for aircraft emergency.

The devices were also used to calibrate very-long-distance underwater monitoring stations that could detect submarines, and lots of other stuff, from hundreds and thousands of miles away. I’ve flow several missions across the North Atlantic where we would drop one or more of these at specific locations and times. The monitoring stations knew exactly where and when the charges would be dropped, so they could calibrate their gear, which included directional hydrophones.

Toward the end of my submarine-attacking time, we shifted to an electronic signal that had a lot more codes available. When it hit the water and began sinking, it transmitted a very strong coded sound that served the purpose without an explosion. These were a lot safer, but not as much fun as the earlier versions that went BANG.


Thank YOU SO MUCH MELL!!! So appreciative for your insight and information on this. Most of all, thanks for your service to our Country. I thought this thing was super interesting but had no quality information on it. Thanks again, big time. Very, Very, cool!


Good explanations Mel.
I put a picture and explanations about the electronic devices you are talking about.
Safer than the explosives ones, but enough dangerous then the submarines still didn’t like them !

I didn’t know you were working in the underwater field.


I believe we may have discussed this in the past on a trading expedition you made to Tallahassee some years ago, but my memory fails me. What Squadron were you in and when? NAS Jax?

Mel, do you happen to have a picture of how these are actually launched/dropped from the plane? Are they manually thrown out a window or possibly shot threw a specialized tube or port? Are they wing mounted, belly mounted?

JP, I’d love to see a picture of the replacement device if you have one handy.

So excited to find this type of information. I thank both of you. I knew someone here would know something about it. I had no clue I would be so fortunate to have answers from a hero who actually used them. VERY, VERY COOOOOL!


JP, I’d love to see a picture of the replacement device if you have one handy.

Wow! thanks so much JP! I actually had one of those a few years ago and was never sure what it was. I was told it was some kind of radio device subs used. You rule, JP!

PS: Do you happen to know what the diameter of that device is JP? I wonder if it is the same as its predecessor?

OK guys; a bit more info.

I used these devices when I was flying the Lockheed P-3 Orion series of anti-submarine warfare (ASW) aircraft from 1968 until 1983, when I retired. Guy, you have a good memory. Yes, most of my time was at the Naval Air Station (NAS) Jacksonville, FL. I had tours in VP-24 (Batmen), VP-30 (Pros) as a flight instructor, and VP-56 (Dragons). We did three deployments to Keflavik, Iceland, which was the best soviet sub-catching place in the Atlantic, and one to Bermuda. I ended up as the Senior Test Pilot at the Naval Aviation Depot in Jax, where the P-3’s and A-7’s went for major overhaul. After they had been taken apart, overhauled, and put back together, I got to fly them to verify the work.

Those interested in the P-3 can just Google P-3 Orion, and have an interesting time reading all about the world’s best ASW airplane. I was fortunate to have flown every model, and helped design one, the TP-3.

The P-3 carries lots of ordnance, which has changed over the years. In the early days, we carried depth charges, 5-inch rockets (to penetrate a surfaced submarine’s pressure hull), 2.75-inch rockets, MK-46 torpedoes, special weapons (don’t ask), and AGM-12B Bullpup missiles. I got to sink a destroyer with Bullpups (exercise, on a surplus U.S. WWII ship). We could also lay a minefield of 5,000-pound mines.

Some of the ordnance was external, on the wing stations, and the P-3 also has a big bomb bay for internal loads. The airplane also carries sonobuoys, which listen for subs. These can be fired from external chutes, or from an internal “free fall” chute that can be used when the plane’s not pressurized. We used the free-fall chute to launch the devies mentioned in this thread. I don’t remember them ever being on a wing or bomb bay station.

That’s probably more than you care about, but still, it’s ordnance.


In France we have Breguet Atlantic.
They were the first airplanes specialy designed for ASW (they are not existing planes converted for this job).

They can lauch a lot of sonoboys (either French, or Canadian).
I know pretty well the sonoboys beacuse, I designed some of them when I was working in Thomson (Thales underwater systems).

Breguet atlantic are also used not only on sea but also on ground to give directions to Jaguar planes.(and the sonoboys also ! lol!)
Good job in Tchad for example. lol!

The directionnal hydrophones, Mel is talking about, are most often hydrophones arrays either lying on the bottom of the sea in special locations or made by sonoboys.

Special weapons Mel ?? Hum !
explosive weapons or electronic weapons ??

Submarine eletronics warfare used to be more funny and interesting than radiocommunications and air electronics warfare.

Now the interest in submarine warfare is less because the threat is no more coming from countries with sophisticated products like Russian subs but from other countries being less " industrialised".
No need to drop hydrophones 300 meters below the sea level to detect very deep submarines if the bad guys have only small boats.


You guys rule! Amazing information. Thank you so much. By the way, I found out the device pictured was Canadian made. Very grateful for your help and detailed info.

PS: I am going to post a crazy 37MM thing in a separate thread next. Take a look at it to see if you can ID it. REALLY WILD!!!

If anyone is really interested, I have a box of the entire P-3 Orion loading and arming manuals somewhere in the basement, come and get it, it is heavy though.