08/16/2025
Anti-Submarine Warfare, or ASW, was an important mission for NAS South Weymouth. During WW2 the base's entire purpose was to support ASW blimp operations and during the post-war era the Naval Air Reserve commands on the base were heavily oriented towards ASW.
I found some digitized ASW related audio recordings from WW2 out on the Internet that may interest you. You can find the original source files at https://maritime.org/sound/index.php
There are three different sets of sound files of interest accessible via the link presented above. You can listen to them by clicking on the speaker icon located next to each file description. To download a sound file, click on the speaker icon associated with it, then in the black screen that comes up click on the three vertical dots on the right hand side of the white oval, then select “download” in the pop-up. You will need to do this separately for each sound file that you want to download. The sound files will download in MP3 format. You can put these on a USB stick and play them in an MP3 player or you can burn them to a CD using MS Windows and play them in a CD player. Of course, you can also just click on the sound files and play them with your PC or smartphone.
The three sets of sound files are:
* Attack on Imperial Japanese Navy Submarine I-52
* Expendable Radio Sonobuoy Training Records, 15P3
* Sonar Training Record Series D16
Some notes on these sound files follow:
The Navy began to use sonobuoys on a limited basis starting in August 1942. At first they were used only by blimps, but by June 1943 they were employed by all types of aircraft used for anti-submarine warfare. The earliest sonobuoy systems were very simple in comparison to what we used. The aircraft were equipped with an ARR-3 sonobuoy receiver and CRT-1 sonobuoys. The early sonobuoys were pre-set to specific frequencies at the factory and were color coded with a painted stripe to indicate which frequency they were set for. The colors used were purple, orange, blue, red, yellow, and green. These were passive buoys that had hydrophones that picked up underwater sounds and transmitted them to the aircraft. The ARR-3 sonobuoy receivers had an on-off switch, a volume control, and a tuning k**b. That’s it. They way the early system worked was fairly simple. To search for a submarine, a purple sonobuoy was dropped on the datum, in other words, the location where the submarine had been seen or was expected to be. The aircraft then flew a cloverleaf pattern (you should remember what that was), with the purple sonobuoy at the center of the cloverleaf. A sonobuoy was dropped just before each turn, generally in the order of purple (at the center or datum), orange, blue, red, and yellow. The green color was reserved for use as a spare in case of a failure of any of the other colored sonobuoys. The early sonobuoys were generally thrown by hand out of the aircraft but later in the war dispensers were employed that were fitted to the bomb bays or wings of aircraft. Again, the early sonobuoys were passive listening devices only. The tuning k**b on the ARR-3 sonobuoy receiver turned a color coded wheel that showed the color and frequency of the sonobuoy selected. The operator turned the dial from one color/frequently to another, listening for the sounds coming from the submarine. Through comparison of relative volume and Doppler, the operator was supposed to determine the position of the submarine in relation to all the sonobuoys in the pattern, and by so doing determine its approximate location.
The two sound files associated with “Attack on Imperial Japanese Navy Submarine I-52” are wire recordings from an actual ASW search and attack operation flown off the aircraft carrier USS Bogue on June 24, 1944. The I-52 was operating in the south Atlantic en-route to Germany. The submarine was carrying a cargo of gold, silk, o***m, rubber, and other goods in payment for transfer of various German military technology. Sonobuoy equipped Grumman TBF Avengers operating from the USS Bogue detected, tracked, and then sunk the I-52. The audio recordings carry the ICS and sonobuoy communications from Avenger that sank the submarine. You will hear references to dropping “the gizmo”. That was a reference to the Mark 24 acoustic homing torpedo, code named FIDO, that was dropped near the submarine and sunk it. This thing was extremely secret at that time and you were not allowed to mention it by its actual name, which is why they referred to it as a “gizmo”. The USS Bogue was part of a task force composed of five destroyers. In the audio recording you will hear the active sonar pings from these destroyers. During WW2 shipboard sonars employed tuning forks as their sound sources and that’s why the sonar pings sound the way they do.
The sound files associated with “Expendable Radio Sonobuoy Training Records, 15P3” and “Sonar Training Record Series D16” are recordings of actual underwater sounds used to train early sonobuoy operators during the final years of WW2. The last two sound files in “Expendable Radio Sonobuoy Training Records, 15P3” are abridged and annotated segments of the I-52 engagement.
It is worth noting how sonobuoy operators were trained in those days. They would arrange five sonobuoys in a large sound deadened room as if they were deployed in the standard cloverleaf pattern. In another room there would be sonobuoy operator trainees, wearing headphones, seated behind ARR-3 sonobuoy receivers. A record player playing submarine propeller and machinery sounds was set up in the room with the sonobuoys, connected to a speaker on a long cord. The speaker was moved around the room to simulated the motion of the submarine. The sonobuoys would transmit the sound from the record to the trainees, and they would then try to determine where the “submarine” was.
Here are some photos showing this type of sonobuoy operator training setup in use at NAS South Weymouth during early 1945. This was operated by the ZJ-1 Detachment in LTA Hangar 2. Two photos show CRT-1 sonobuoys arranged on the floor of the soundproofed room in a standard pattern with the record player at left and training personnel demonstrating how the speaker was moved around the sonobuoys to simulate a moving submarine. The other photo shows an ARR-3 sonobuoy receiver in use in the classroom.
