When leaving Guantanamo Bay on 11 March: American destroyers USS Leary (DD 158) (LtCdr J.E. Kyes, USN) and USS Biddle (DD 151) (LtCdr T.A. Torgerson, USN) and American patrol craft USS PC-567 and USS PC-627
Joining from Curaçao as reinforcements in the afternoon of 13 March: American destroyers USS Madison (DD 425) (Cdr J.W. Hager, USN), USS Lansdale (DD 426) (LtCdr V. Havard, Jr., USN) and USS Charles F. Hughes (DD 428) (LtCdr B.S. Copping, USN)

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

On 11 March 1943 the convoy GAT-49 was formed off Guantanamo Bay with 16 merchant ships, escorted by USS Leary on starboard bow, USS Biddle on port bow, USS PC-567 on starboard flank and USS PC-627 on port flank.

U-68 surfaced and chased the convoy after picking up a sound bearing at 07.37 hours on 13 March, approaching undetected from astern in clear weather and a moonless night. Between 09.51 and 09.52 hours, the U-boat fired three torpedoes at a freighter and a tanker about 170 miles northwest of Curaçao and hit the Cities Service Missouri with one of them. The Ceres was hit by two torpedoes in a second attack at 10.24 hours. The escorts failed to detect the U-boat which left the area after finishing off the damaged tanker behind the convoy. The survivors of both torpedoed ships were picked up by USS Biddle.

Three destroyers were sent as reinforcements from Curaçao following the attack, arriving in the afternoon of 13 March. The next morning, five merchant ships bound for Aruba were detached under escort of a local patrol craft and three hours later three ships bound for Curaçao left the convoy, escorted by the three destroyers. USS Biddle proceeded to Willemstad to land the survivors and then rejoined the convoy, which consisted of nine ships after being joined by one merchant from Aruba and two more from Curaçao. In the morning on 17 March, the convoy GAT-49 arrived in Port of Spain, Trinidad.