In the convoy is the rescue ship Goatland equipped with HF/DF.

The wolfpack Leopard of 7 boats: U-254 (Kptlt. Loewe), U-353 (Oblt. Römer) ++, U-382 (Kptlt. Juli), U-437 (Kptlt. Schulz), U-442 (Korvkpt. Hesse), U-620 (Kptlt. Stein), U-661 (Oblt. von Lilienfeld) *

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

Only U-221 gets to the convoy in the night of the 12th and in three approaches sinks three ships. The boat does not loose contact and during day brings up U-258, U-216, U-599 and U-607. These boats are located by HF/DF and the escorts keep them at bey. U-258 is shelled by the Eglantine but escapes.

After pressing an u-boat under water, some escorts cannot catch up with the convoy in time for the night. U-221 slips through the depleted screen and sinks two ships. Also U-607 and U-661 attack and sink each a ship. The Viscount damages the U-607 in an counterattack.

In the morning U-618 sinks one ship, while U-615 is driven off by the Montbretia. Contact is lost and then regained by U-216. The Gruppe Leopard breaks off the fight around ONS-136 and is directed towards SC-104.

The escorts however manage to beat off all attacks in the night : The Montbretia drives off U-661, the Acanthus damages U-607 and U-661 is rammed by the Viscount. Potentilla and Eglantine damage the U-254.

Also by day on the 15th no U-boat gets close to the convoy : the Fame drives off U-258 and Acanthus deals with U-599 and U-442. Also air escort is provided now and liberators chase away U-437 and U-615.

On the next day U-258 stays in contact but due to the strong air escort, no boats can be brought up. U-353 is sunk by the Fame when trying to make a submerged daylight attack and U-571 is damaged by the Potentilla. On the 16th the operation is broken off.