Built by the Standard Shipbuilding Corporation and launched from their New York yard on 29th January 1921 the San Tiburcio measured 413.0′ x 53.4′ x 31.1′ and weighed 5995 gros tons, 3618 net tons. Her triple expansion steam engine by Sun Shipbuilding and Drydock Company generated 544 net horsepower. The construction of these simple but extremely seaworthy tanker vessels built to transport oil was to prove invaluable when she was sunk in Moray Firth in the spring of 1940. Basically a long steel box divided into 33 water tight compartments the ships of the Eagle Fleet served their company well in the years leading up to the Second World War. When fully loaded the ships low freeboard resulted in the decks being continually awash but they remained stable and safe even in this condition. As a result a ‘flying bridge’ ran the full length of the ship connecting the three islands of her fo’c’cstle, her bridge and her engine room at the rear allowing the crew to move freely around the ship even in rough conditions. Requisitioned by the Admiralty at the outbreak of war the ships continued to ply the oceans around Britain transporting much needed fuel for the countries’ warships and merchant fleet.
It was on this duty in May 1940 that the San Tiburcio left Scapa Flow destined for Invergordon in the Cromarty Firth with a cargo of 2193 tons of fuel oil and 12 aeroplane floats. She was under the command of Captain Walter Frederick Fynn with a crew of 39 men.
Earlier in the year, on February 5th, the German U-boat U-9 had loaded her deadly cargo of mines and set out from her home port of Wilhelmshaven under the command of her skipper Oberleutnant Wolfgang Luth. The patrol was planned to lay the mines of the Scottish East coast in preparation for Operation Nordmark…. a foray into the North Sea by the German battleships Scharnhorst, Gneisenau and Admiral Hipper intent of engaging British warships near Scapa Flow. The mines were successfully laid off Cromarty on February 10th and U-9 left the area undetected and returned safely to port.
On 4th May Fynn navigated his ship down the Scottish east coast and was only a few miles from his destination in the Cromarty Firth when the ship was rocked by a huge explosion. She had hit one of U-9’s mines. The massive explosion ripped an enormous gash more than 50 feet long in the heavily laden ship and within minutes the weight of the two ends of the ship tore the ship in two splitting to the rear of the midships superstructure. Thankfully, despite the devastating damage, the construction of the ship, with its watertight compartments, kept the two sections afloat for more than 30 minutes enabling the crew to escape with no fatalities. As they pulled away in the ship’s boats they watched as both sections sank to the bottom within minutes of each other.
The Wreck Today
The wreck of the San Tiburcio has become one of the iconic wreck dives in Scotland as the two well preserved sections of the ship sit upright in 30 metres of sheltered water and rising 6 metres from the seabed. She lies in position 57°46.567’N, 03°45.533’W oriented 022°/212°. The forward section is most in tact and covered in encrusting sealife. The stern section lies only 50 metres from the bow section and, although more damaged and broken, still provides an interesting wreck to explore. A four inch gun fitted for defensive purposes is clearly visible on the port side.