Potrero del Lano
Teddy Suhren, known for his irreverence even to superior officers (he once told Gross Admiral Donitz that an exhortation to attack a nearby convoy with vigor was belittling and unnecessary, for which he was half-jokingly spanked), kicked a hornet’s nest when he sank the neutral Mexican tanker Potrero del Llano in the Straits of Florida north of the Cay Sal Bank. Combined with the sinking of the Faja del Oro by Rasch in U-106 exactly a week later, these attacks would push Mexico to issue a declaration of war against Germany and the Axis within a month, making the Gulf of Mexico a much less safe haven for German submarines.
Compounding the outrage and confusion, the Mexicans claimed that their ship clearly illuminated as a neutral with Mexican flags prominently displayed, and that Suhren had been sighted trailing the ship for at least half an hour and thus had ample opportunity to ascertain it’s neutrality. Suhren for his part countered that he mistook the Mexican flag for a fake Italian insignia, though his superiors later claimed that U-564 found the ship darkened and not illuminated at all. Obviously politics played a heavy part in the aftermath, but the sinking itself went along the now familiar and deadly lines of so many attacks like it.
According to Barnette and U-Boat, the Potrero del Llano was the former Italian Lucifero but seized my Mexico in April 1941 when Italy joined the Germans. It was built in 1912 by Palmers Shipbuilding & Iron Company Limited, Hebburn-on-Tyne, England, as the F. A. Tamplin for an eponymous shipping firm (formally T. W. Tamplin & Co.) of London. Her dimensions were 4,000-tons GRT, 364 in length, and 47.5 wide. In 1921 she was named Arminco after being sold to the SA d’Armement, d’Industrie & de Commerce, of Antwerp, Belgium. From 1930 to 1941 it traded as the Lucifero for the Società Italiana Transporti Petroliferi (SITP), of Genoa, Italy. Interned the 10th of June 1940 in the same port as the Columbus, Aruaca and others, on the 8th of December 1941 (the day after Pearl Harbor), it was seized by Mexico. Put to work for Petroleos Mexicanos (Pemex), she was given her final name and registered to Tampico, on the Caribbean Sea.
At the time of her sinking the Potrero was enroute from Tampico for New York with 6,132 tons of oil. She was under the command of Captain Gabriel Cruz Diaz who lead a total crew of 35 souls, all of them Mexican nationals. In position 25.35N and 80.06W (between South Beach Miami and the northernmost Florida Keys), she was struck by Suhren just east of Cape Florida. The attack occurred at 11:55 PM on Wednesday May 13th, 1942. According to Quatermaster Eduardo Sibaja y Ramirez, “four spotlights [were] directed at the large Mexican flags painted on either side of the ship”. (Barnette, Vol. 1, p.195). While stumbling drowsily towards the bridge, Sibaja witnessed the entire structure obliterated by the explosion and impact of the torpedo. He “and several others recalled seeing the conning tower of a submarine moving away swiftly as they prepared to abandon ship.” (Id.). According to Barnette, “thousands of individuals lined the beaches of Miami to watch the blazing vessel drift northward. For hours they sat mesmerized by the massive flames shooting skyward.” (Id.)
Twelve men were killed in the attack, outraging the Mexican people and government against German business interests and people in that country. The 22 survivors were landed in Miami, but one of their number died on shore of wounds sustained in the explosions. The exact location of the Potrero del Llano, like the intentions of the skipper of the submarine which attacked her, remain unclear to this day.