Expendable Radio Sonobuoy Training Records, 15P3:
U.S. Navy, Bureau of Aeronautics – Special Devices Division
Device 15P3
These are 78 RPM records prepared by Columbia University, Division of War Research at the U.S. Navy Underwater Sound Laboratory, Fort Trumball, New London Conn.
A cassette tape containing a copy of these records was discovered by a group researching I-52 for potential salvage. They were kind enough to provide a copy for our use. Most extraordinary are the final records (XIX and XX) which are pieced together from an actual attack on Imperial Japanese Navy submarine I-52 during 1944.
The user manual including instructions on how to use the records and the text of the records is availablehere.
An illustration and short description of the WW II radio sonobuoy hardware may be found at:https://www.hnsa.org/doc/sonar/chap16.htm#fig16-19 and
https://www.hnsa.org/doc/sonar/chap16.htm#pg299

I. Introduction to Submarine Sounds: (1) water noise, (2) propeller beats, (3) machinery sounds, (4) auxiliary motor sounds, (4) propeller beats and machinery sound together. All recorded from USS Bluegill, an American fleet type submarine.
II. Cavitation: Effect of Depth and Speed (Fleet Type Submarine). (1) Periscope depth, 7 knots, (2) Periscope depth, 3 knots, (3) Periscope depth, 6 knots, (4) 250 ft. depth, 6 knots, (5) 250 ft. depth, 8 knots. Old type submarine was S-20.
III. Cavitation: Effect of Depth and Speed (Old Type Submarine) (1) Periscope depth, 3 knots, (2) 100 ft. depth, 3 knots, (3) Periscope depth, 2 1/2 knots, (4) 100 ft. depth, 2 1/2 knots
IV. Estimation of Submarine’s Speed by Counting RPM (1) Fleet type submarine, 120 RPM, 6 knots (2) Old type submarine, 150 RPM, 3 knots (3) Fleet type submarine, 140 RPM, 7 knots
V. Effect of Underwater Range on Submarine Sounds (1) Range – 200 yards, (2) Range – 1,000 yards, (3) Range – 200 yards, (4) Range – 1,000 yards, (5) Range 300 yards The first three examples are of USS Bluegill, and the last two USS Pintado, both fleet type submarines.
VI. Comparison Between Sounds Produced by Surfaced and Submerged Submarine. (1) Periscope depth, 3 knots, (2) On surface, 7 knots, (3) Periscope depth, 3 knots, (4) Blowing tanks and surfacing
VII. Interfering Sounds: Submarine and Destroyer Escort (1) Submarine, periscope depth, 3 knots, (2) DE, 15 knots, (3) Submarine, 500 yards; and DE, 1500 yards, (4) Submarine, periscope depth, 5 knots; DE, 10 knots, approaching from 1,000 yards The DE was a 1720 class and the submarine was USS S-20 built in 1920.
VIII. Sounds Produced by Activities Aboard Submarine: (1) Operating trim pump, (2) Bleeding down ballast tanks, (3) Operating radar-training motor-generator, (4) Pounding on pipes and bulkhead, (5) Operating torpedo data computer, (6) Slamming bulkhead door, (7) Announcing over P.A. system, shouting of crew, (8) Sounding alarms, (9) Charging batteries Recorded 50 feet from the conning tower of USS Cavalla
IX. Marine Life Sounds. (1) Croakers, (2) Black drum fish, (3) Snapping shrimp, (4) Garibaldi, (5) Porpoises
X. Surface Craft Sounds. (1) Surf Landing Boat, 15 knots, (2) Cruiser (USS San Juan), 9 knots, (3) Destroyer (USS Nicholson), 14 knots, (4) Battleship (USS South Dakota), 7 knots, (5) Freighter (Bethore), 8 knots, (6) Destroyer Escort (DE-794), 15 knots
XI. Torpedo, Mine-sweeper, and Foxer Sounds (1) German electric torpedo, (2) German air torpedo, (3) Acoustic minesweeper, (4) Foxer
XII. Depth Charge Explosions (1) Range-2 miles, (2) Range-1 mile, (3) Range-1,000 yards, (4) Range-100 yards, (5) Depth charges as heard aboard a submarine, 100 yards from buoy These are Mark 47 depth charges dropped from aircraft. Each explosion is about 15-20 seconds, explosion sounds are sometimes as long as 60 seconds.
XIII. Identification Test Nine examples to be identified.(1) Water noise only, (2) Submarine propeller beats or sub. propeller beats with machinery whine, (3) Machinery whine from submarine, (4) Water noise only, (5) Submarine’s auxiliary motors (bow and stern planes), (6) Minesweeper, (7) Sub propeller beats and machinery whine, (8) Croakers, (9) Submarine charging batteries, (10) Submarine propellor beats and depth charge.
XIV. Identification and Turncount Test Six examples to be identified and examples for turncount test.(1) Submarine propeller beats or sub. propeller beats with machinery whine, (2) Water noise only, (3) Submarine propeller beats and minesweeper, (4) Surfaced submarine running on Diesels, (5) Destroyer Escort, 15 knots, (6) Depth charge, (7) RPM-120, Speed-6 knots.
XV. Search Problem Three buoy patternOrange, Purple and Blue are arranged as a right triangle with O on top. The submarine is below Purple and Blue between the Purple and Blue. Submarine is a fleet type submarine.
XVI. Search Problem Five buoy patternThe buoys are in a cross with Orange on top (north), Purple in the center, Yellow on left, Blue on right and Red below (south). The submarine is traveling south below the red buoy. The target is an S-type submarine.
XVII. Search Problem Five buoy patternThe buoys are in a cross with Orange on top (north), Purple in the center, Yellow on left, Blue on right and Red below (south).The sub is going in the direction of the Yellow buoy, but is close to the Orange buoy.
XVIII. Search Problem Five buoy patternA sub is heard on Yellow frequency. On the second round a DE is heard on Purple and Blue and the sub is getting weaker on the Yellow. Both vessels are going in a westerly direction, the sub leaving the pattern and the DE entering.
XIX. These are sounds heard during actual anti-submarine operations during WW II. These are pieced together from the attack on Imperial Japanese Navy submarine I-52 by PBY aircraft from USS Bogue during 1944.
XX. Continuation of the sounds from the attack on Imperial Japanese Navy submarine I-52