The American escort group A3 (Cdr Heffermann) consisting of the destroyer Gleaves, the cutter Ingham and 4 Canadian corvettes : Algoma, Arvida, Bittersweet and Shediac. In the convoy is the rescue vessel Bury equipped with HF/DF.

The wolfpack Hecht of 6 boats
U-94 (Oblt Ites) *, U-96 (Oblt Hellriegel), U-124 (Korvkpt Mohr) *, U-406 (Kptlt Dieterichs) *, U-569 (KptLt Hinsch) *, U-590 (KptLt Muller-Edzards)

* U-boats that fired torpedo or used the deck gun

After the disastrous chase on the convoy HG-76 in December 41, the BdU has given up for a while convoy battle. Most of the boats are sent to the unprotected coasts of America. As the defence gets more and more organised and the opposition gets tougher, plans arise to attack again the vital North Atlantic convoy routes. Apart from some chance meetings (e.g. ONS-67) there weren't for the past six months any convoy battle to speak off when the group Hecht is sent out in May.

U-569 makes contact on the 11th and leads U-94 and U-124 to the convoy. The boats attack in the night and U-124 sinks 4 ships in 2 approaches, U-94 sinks one and U-569 gets a possible hit on a ship.

In the next night the other boats get to the convoy but only U-94 sinks 2 ships in 2 approaches. U-406 misses an escort due to torpedo failure. Then contact is lost in bad weather.

The failure of the escort is in part explained by their inadequate use of the HF/DF bearings provided by the Bury.