Submarine USS Gunnel launched.

ATLANTIC OCEAN: At 2358 on 16 May, 1942, the unescorted and unarmed Ruth Lykes was hit amidships on the port side by a dud torpedo from U-103 that glanced off the ship, when steaming on a zigzag course at 10 knots off Cape Falso, Nicaragua. The U-boat then surfaced and began shelling the ship at 0019 from a distance of 1.5 miles. After about 24 hits in the superstructure and rigging, the engines were stopped and the most of the eight officers, 21 crewmen and three passengers abandoned ship in two lifeboats, while several others jumped overboard and swam to a raft. The Germans ceased fire to let the crew time to abandon ship and then reopened fire at the vessel, which sank with a heavy list to port at 00.44 hours. The U-boat picked up one crewman who had injured himself by falling on wreckage as he jumped overboard. His wounds were threatened and placed in a lifeboat after being questioned. When they were asked for bandages, winter provided them four packages of bandages and cigarettes and stated - "I am sorry, but you can thank Mr. Roosevelt for this." Three officers and two crewmen were lost. The 27 survivors were picked up after twelve hours by the Norwegian motor merchant Somerville and landed them at Key West, Florida, but one crewman died from wounds on the vessel.

At 0454, the unescorted Fort Qu'Appelle, on her maiden voyage was torpedoed and sunk by U-135 north of Bermuda. The master, 12 crewmembers and one gunner were lost. Ten crewmembers and one gunner were picked up by minesweeper HMCS Melville and landed at Shelburne, Nova Scotia on 19 May.

After leaving New York, the Challenger broke down and steamed to Savannah for repairs, but there were no facilities available and so she limped unescorted to Trinidad. At 0952 on 17 May 1942, U-155 caught the ship on a slow zigzagging course 25 miles east of Granada and fired two torpedoes. The first struck the #3 tank amidships on the starboard side and the second abaft the #5 hold, causing the after magazine to explode. This destroyed the entire stern section and blew the 4in gun completely of its mounting. The engines were stopped and an SOS was sent, but received no reply. The gun crew spotted a light off the port beam and opened fire with the forward 3in gun (the ship was also armed with six .50cal guns) at 3000 yards. 18 rounds were fired without effect. The light eventually crossed the bow and disappeared to the southwest. The ship carried nine officers, 32 crewmen, eleven armed guards and twelve passengers. The ship settled slowly and sank by the stern after one hour. Two armed guards, one passenger and five crewmen died on the vessel. 56 men abandoned ship in the two port lifeboats and were picked up eleven hours later by USS Turquoise, which was led to the survivors by an aircraft and were landed at Trinidad. The master John G Waller later experienced another sinking, when he commanded the African Star, which was sunk by U-172 on 12 Jul 1943.

At 0217, the unescorted San Victorio, on her maiden voyage, was hit by two torpedoes from U-155 and sank southwest of Grenada. The tanker had been spotted at 0033 hours and missed by a first torpedo at 0114. The U-boat had to crash dive 10 minutes after the hits because a flying boat was sighted. The master, 43 crewmembers, seven gunners and one passenger were lost. The sole survivor, gunner Anthony Ryan, was picked up by patrol yacht USS Turquoise and landed at Trinidad.

At 2104, the unescorted Barrdale was torpedoed and sunk by U-156 east of Martinique. One gunner was lost. The master, 44 crewmembers and seven gunners were picked up by the Argentinean merchant Rio Iguazi and landed at Pernambuco.

At 1830, the unescorted and unarmed Foam spotted U-432 on the surface about 85 miles south of Halifax. At the same time, the U-boat began shelling the trawler. The first shot passed over the bow and the master immediately stopped the engines. The second shell hit the bow and U-432 fired approximately 29 shots before the two officers and 19 crewmembers abandoned ship in one lifeboat and a raft. Approximately 15 more shots were fired to sink the ship; many of them did not explode and passed through the vessel. One man on the raft later died of wounds. 17 men in the lifeboat steered for land and arrived at the Sambro Light Ship 30 hours after the attack. A Canadian patrol boat took them off and landed them at Halifax. Corvette HMCS Halifax picked up the remaining three survivors from the raft two days after the attack and landed them at Boston.

At 0534, the unescorted Gulfoil was torpedoed by U-506 about 75 miles SW of the Mississippi River Delta. The ship had maintained a zigzagging course up to 0500 that day at 9.5 knots. The mate on watch spotted the first torpedo before it hit the starboard side amidships at the #4 tank. The explosion blew the catwalk away from the mainmast to the midships house. 15 seconds later, a second torpedo struck the engine room, killing the three men on watch below. After the first torpedo the vessel list about 40° to starboard, but partially righted herself after the second hit. The tanker sank within two minutes with a heavy starboard list. The crew had no time to launch the boats, only five officers and 14 crewmen out of eight officers, 28 crewmen and four armed guards (the ship was armed with one 4in and two .30cal guns) managed to leave the ship on two liferafts. After 35 hours, the survivors were picked up by the Benjamin Brewster and taken to Galveston, Texas.

At 1802, the unescorted Skottland was torpedoed on the port side by U-588 about 20 miles WSW of Cape Sable, Nova Scotia. A torpedo struck aft between #3 and #4 hatch and a second is assumed to have hit amidships near the fire room. The explosions stopped the engines and the ship lost all power. Most of the crew was on deck as they had just completed a gunnery drill and abandoned ship in the starboard lifeboat because the port boat had been destroyed and the motorboat capsized. They launched the boat with great difficulty because of the heavy list to port and some of the men later transferred onto two rafts that floated free after the ship sank by the stern in about 30 minutes. The men in the boat rowed around to search for a missing stoker, but did not find him and assumed that he had been killed by the explosions. The survivors were picked up by the Canadian lobster boat O.K. Servise 4 (Master SE Himmelman) after being spotted by a Canadian aircraft and taken to Boston, where they arrived the following morning. Nine men had been injured and four of them were taken to a hospital upon arrival.