U-boat Archive - U-231 - USS Block Island Report - Radar Decoy Balloon, Recovery of

CVE21/A16-3/S67 OF10/Bn

(003)

U. S. S. BLOCK ISLAND

From:	The Commander Task Group 21.16 (CO U.S.S. BLOCK ISLAND).
To:	The Commander in Chief, United States Fleet.
Via:	The Commander Fleet Air, Norfolk.

Subject:	Radar Decoy Balloon, Recovery of.

References:	(a) United States Fleet Anti-Submarine Bulletin of November 1943, Pages 6 and 7.
	(b) United States Fleet Anti-Submarine Bulletin of September 1943, Page2.

1. A radar decoy balloon was recovered from the sea 14 January 1944, in close proximity to the location of several submarine encounters by surface and air units during the proceeding twelve hours. The balloon, believed to be the first of its kind recovered in the North Atlantic, will be delivered to the Commandant Fifth Naval District (Office of Naval Intelligence) upon arrival in port.

2. While proceeding to the scene where life rafts containing German survivors of a U-boat sinking had been sighted by planes from BLOCK ISLAND, this ship sighted a red balloon. Immediately thereafter, the following transmissions were exchanged over TBS by U.S.S. BULMER (voice code "TANNER") and U.S.S. BLOCK ISLAND (voice code "EVOY"), zone time plus two:

1050	-	Evoy from Tanner:
		Sighted a red balloon with silver streamers on my starboard beam - possibly a radar decoy. Request permission to intercept.

1051	-	Tanner from Evoy:
		Intercept if possible.

1100	-	Evoy from Tanner:
		Made it first pass. Looks like it might be it. Would you like me to pass it to you after this operation?

1101	-	Tanner from Evoy:
		Retain until fueling.

3. The decoy was picked up by BULMER at 1257 GCT; estimated position, latitude 44⁰ 49' North, longitude 20⁰ 18' West. This was about twenty miles north of the eleven German life rafts.

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	CVE21/A16-3/S67 OF10/Bn
	(003)

	Subject: Radar Decoy Balloon, Recovery of.
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	4. The decoy found was a red rubber balloon approximately one foot in diameter, deflated, and from two to three feet in diameter, inflated. The mouth of the balloon was tied with fine cord going to a metal clip. To the clip was fastened a ring attached to fourteen feet of fine wire-wrapped chord. Three aluminum foil streamers, paper backed, four centimeters wide (about 1-1/2") were attached to the cord. The streamers were torn off during recovery, the longest remaining one being 2-1/2 feet in length; however, it is possible that they were originally considerably longer than this. The streamers were spaced 6-1/2 feet apart with the first one about eight inches below the balloon. Below the last streamer, the wire-wound cord was fastened by ring and clip to four feet of synthetic cat gut line going to a combination metal reel and float five inches in diameter. The total length from float to balloon was about eighteen feet, although greatly increased length could have been obtained by unwinding more cat gut from the reel, which contains a considerable quantity of the line.

	5. The decoy appeared to be almost identical with that described in the November Anti-Submarine Bulletin, reference (a), as having been recovered by U.S.S. BUCK. It was also similar to that described by U-boat prisoners in the September Anti-Submarine Bulletin, reference (b), except that the red balloon definitely was not colorless and transparent when inflated, but very red in color.


	L. C. RAMSEY.

	Copies to:
	VCNO (ONI)
	DIO - 5ND