Japanese Submarine I-52 (1943) - US Task Force

US Task Force

A US task force assembled as a submarine hunter-killer group, consisting of the escort carrier USS Bogue and five destroyer escorts, en route to the United States from Europe, was ordered to find and destroy the Japanese submarine. This task force departed from Casablanca on 15 June 1944, and was commanded by Captain Aurelius B. Vosseller. It also had 9 FM-2 Wildcats and 12 TBF-1C Avenger of VC-69 on board. The task force, on its way from Hampton Roads to Casablanca, had sunk another Japanese submarine, the Type IX RO-501 (formerly U-1224) on 13 May 1944. This was a very effective force, sinking 13 German and Japanese submarines between February 1943 and July 1945.

The five destroyer escorts were:

• USS Francis M. Robinson, Lieutenant J. E. Johansen.
• USS Haverfield, Commander T. S. Lank, TF 51 commander.
• USS Swenning, Lieutenant R. E. Peek.
• USS Willis, Lieutenant Commander G. R. Atterbury.
• USS Janssen, Lieutenant Commander H. E. Cross.

Arriving in the area of the meeting, the carrier began launching flights of Avengers at around 23:00 GMT to search for the submarines. U-530 escaped undetected.

At approximately 23:40 on 23 June, Ed Whitlock, the radar operator in Lieutenant Commander Jesse D. Taylor's Avenger, detected a surface contact on his malfunctioning radar (only the right half of its sweep was working). Taylor immediately dropped flares, illuminating the area, and attacked. After his first pass, he saw the depth charge explosions just to starboard of the submarine — a near miss — and the submarine diving. Taylor dropped a purple sonobuoy, a newly-developed device that floated, picked up underwater noise, and transmitted it back. A searching aircraft usually dropped these in packs of five, named purple, orange, blue, red and yellow (POBRY); the operator was able to monitor each buoy in turn to listen for sounds emitted by its target.

Taylor then began a torpedo attack, dropping a Mark 24 "mine" torpedo. That term was used for what was code-named "Fido": the first Allied acoustic torpedo, developed by the Harvard Underwater Sound Lab, which homed in on the sounds of the submarine. Fido was designed to be a "mission kill" weapon — it would damage the submarine so badly it would have to surface, rather than destroying it completely. Within minutes, the sonobuoys transmitted the sounds of an explosion and mechanical break-up noises.

As Commander Taylor's watch ended, the operators on Bogue and Taylor all thought he had sunk the sub. However, as Taylor's patrol ended, he was relieved by Lieutenant (junior grade) William "Flash" Gordon, accompanied by civilian underwater sound expert Price Fish. They arrived on the scene just after midnight, and circled with Taylor for some time. At about 01:00 on 24 June 1944, Fish reported hearing some faint propeller noise in the area.

Captain Vosseller ordered a second attack; Gordon checked with Taylor about the exact position of the sonobuoy, and dropped another "Fido" torpedo where he believed the submarine to be. Taylor departed from the area at 01:15, but Gordon stayed to circle the area and listen for any sign of activity. He heard nothing, and was relieved by Lieutenant (junior grade) Brady, who continued to watch and listen, but no further activity was reported. Next morning, Janssen reached the site (15°16′N 39°55′W / 15.267°N 39.917°W / 15.267; -39.917) and found flotsam: a ton of raw rubber, a piece of silk, and even human flesh.

The sonobuoy recording of the last few moments of I-52's sound still survives in the US National Archives in Washington D.C. in the form of two thin film canisters marked "Gordon wire No. 1" and "Gordon wire No. 2" dated 24 June 1944. The wire from Taylor's attack has not been found; however, a set of 78 rpm vinyl recordings that include segments of Taylor's wire recordings has been located. These records were produced during the war for training pilots. On the wire and vinyl recordings Lieutenant Gordon can be heard talking to his crew, along with the sound of a torpedo exploding, and metal twisting. Subsequent to the discovery of the wreck (see below), analysts at the Johns Hopkins University Applied Physics Laboratory, experts in analyzing modern submarine sounds, studied these recordings and concluded that the I-52 was sunk by Taylor. The propeller sounds heard by Gordon were actually from the U-Boat, nearly 20 miles (32 km) away, reaching Gordon's sonobuoys through a "surface duct". This quirk of underwater sound propagation traps sounds in a channel near the surface and can transmit them for many miles. At the time, the Navy credited the sinking of the I-52 to both Gordon and Taylor, as it was uncertain whether the ship was sunk on the first attack.