SS Nickeliner, a US amonia tanker sunk in convoy by U-176 under Dierksen 13 May 1943 along with SS Mambi

Comparison in size between Cuban patrol boat CS-13 and U-176 from a Cuban history site.


           As Nickeliner and Mambi were sunk in the same convoy, same position and at the same time, their accounts should be read together.

             The American steam tanker Nickeliner was built by Dolomite Marine Company of Pittsford, New York in 1938 as Dolomite 4. She was sold two years later to All Waterways Navigation Company of Lake Charles, Louisiana and renamed Nickeliner. Her next owners were the Chemical Marine Company of Lake Charles, Louisiana, to which port she was registered. At the cost of $284,000 she was converted to carry bulk ammonia in 1943 ( Her tonnage was 2,249 tons gross. Nickeliner was the only tankers in the US market custom fit to carry the volatile cargo ammonia.

             On her final voyage the Nickeliner left Nuevitas Cuba at twenty minutes after midnight on the 13th of May 1943 bound in convoy NC 18 for Nicaro (Antilla) Cuba. On board were 3,400 tons of ammonia water destined for the Nicaro Nickel Mines Company plant, which was about to “produce a metal of high strategic value.”

            Her Master was Captain Julius Fridlef Swensson who was responsible for a total of 31 souls on board his ship, one of them a Canadian. These consisted of 15 crew, eight officers and one passenger. The convoy escort of three 83-foot Cuban patrol craft was led by Lieutenant Junior Grade Perez Soto on CS 31. The convoys had to pull into port every 24 or so hours to enable the escorts to refuel.

             U-176 attacked the convoy from the north, roughly six miles north of Manati Cuba as the group of five ships was only three hours into their voyage. At 3:28 whilst the Nickeliner was on course 112 degree east-northeast true and making eight knots a torpedo struck her port blow. The impact sent a geyser of water and red flame one hundred feet into the air. The explosion caused the forward deck plates to buckle. To the men on board it was as though their ship had hit a submerged rock and the bow moved upwards by the impact.

             Twenty seconds later another torpedo struck, this one in the cargo tanks a bit further aft than the first. Ammonia water was sprayed throughout the ship and the instruments on the bridge went dead. The officer of the watch (Captain Swensson was in his cabin at first), ordered hard right rudder and engines full ahead to avoid any other projectiles, but the ship slowed speed significantly as it sank by the bow.

             By 03:38 the engines had stopped, most likely due to damage sustained by both torpedo strikes. The Radio Operator managed to send distress signals, but received no replies. At 3:40 am Captain Swensson and his Chief Officer, Smith Bryant, 36 of Baton Rouge, saw “blinker signals” roughly 500 yards ahead of the ship. The Signalman, Nelson Roy Hood, 21 of Rockwood, Tennessee, then sent a reply asking “identify yourself” which was not replied to.

           Then more signals began about 2,000 yards off to starboard. The signal read “Make Manati” and was repeated. Manati Cuba was the nearest report. After the men had been rescued Swensson asked which of the escorts had sent the signals, however all of them denied sending anything (CS 33, at the front of the convoy simply sailed on, oblivious to the fact that her convoy had been decimated with one hundred percent loss).

             By 03:55 the ship was settled by the bow and two thirds of her length was under water, though she retained an even keel. By 3:55 the ship had been abandoned by all personnel. Captain Swensson commended the calm order of six merchant marine academy cadets who were making their first trip since leaving school.

             At 4:10 Lieutenant Soto on the patrol craft heard several taunts on the radio to the effect of “Don’t take any shit. You are too little to get me, get away with that shit” in a “low and impressive” voice with a Central American accent. At 4:15 the Nickeliner was seen to sink completely by her bow. The men climbed into two lifeboats and were picked up by CS 31 under Lieutenant Perez and taken to Nuevitas.

             On the way into Nuevitas both Perez and Swensson observed a “bum boat” or local inter-harbor cargo ship heading out to where the convoy had just been attacked. Swensson asked Perez if a warning should not be given via radio to help other victims steer clear of the U-boat, to which Perez replied that the bum boat was too small for a submarine to bother attacking.

             Then a US Liberty Ship, the SS Pendleton, came out of Nuevitas while the Nickeliner and Mambi survivors were inbound. Swensson asked again if Perez would warn the ship and when Perez said he would ask his navy to do so, it was too much for Swensson. Swensson had his Radio Operator, Robert Lincoln Thompson, aged 26, fire up an emergency transmitter on the spot and warned the Pendleton about the immediate danger from a nearby U-boat. Heeding this warning, the master of the Pendleton turned around and returned to port.

               The day before the attack the men in the convoy had spotted a small single-engine plane following them which did not reply to signals. The Navy said no single-engine aircraft were in the area. Given the unique value of the Nickeliner to the war effort, it was felt that her loss was due to some fifth column activity, and that the small aircraft might have been doing surveillance for a submarine or Axis shore station.

                As a result the only three people to board her since she left Havana, a port pilot, a customs official and a vendor of sea shells at Cayo Frances, were interrogated and investigated. This general confusion and suspicion was naturally a product of the times in which the men lived, in which convoys could be decimated mere hours after leaving the safety of port.

                An air search for the submarine and any survivors was instituted from Guantanamo that morning, however some blame was given to the Cubans for not broadcasting the loss of the convoy to the Americans sooner. From Nuevitas the Nickeliner survivors were taken to Guantanamo Cuba and repatriated to the US where appropriate. First Mate Bryant Smith and Ordinary Seamen Stanley Mozdzyn and John Arensen arrived in Maimi via Pan-American Airlines plane from Camaguey Cuba on the 16th of May.