As part of a group of six submarines selected for Mediterranean service, UB-47 was broken into railcar sized components and shipped to Pola where she was assembled and launched in June 1916, and commissioned in July.

Over the next year the U-boat sank twenty-two ships, which included the French battleship Gaulois and two Cunard Line steamers in use as troopships, Franconia and Ivernia.

[9] The U-boat could carry up to 27 tonnes (27 long tons) of diesel fuel, giving her a range of 6,940 nautical miles (12,850 km; 7,990 mi)at 5 knots (9.3 km/h; 5.8 mph).

[1] As one of six U-boats selected for service in the Mediterranean while under construction, UB-47 was broken into railcar-sized components and shipped overland to the Austro-Hungarian port of Pola.

[14] Although Italy and Germany would not formally be at war for another ten days,[15] German U-boats in the Mediterranean routinely attacked Italian vessels by posing as Austro-Hungarian submarines and flying the ensign of that country's navy.

[16] Stampalia was an ocean liner of 9,000 gross register tons (GRT) that had formerly been in passenger service between New York and Genoa, and had been one of the first Italian merchant vessels to be armed against submarine attacks.

The British steamer Butetown, en route from Malta to Mudro, was carrying coal and other cargo when she was sent down 55 nautical miles (102 km; 63 mi) west-southwest of Cape Matapan on 8 September.

[18] UB-47 attacked Llangorse, another British steamer, 7 nautical miles (13 km; 8.1 mi) away, sending the ship and her cargo of Canadian oats headed to Salonica to the bottom.

[21] On 4 October, Steinbauer sank the largest ship of his career when UB-47 torpedoed the 1911 Cunard Line steamer Franconia at position 35°56′N 18°30′E / 35.933°N 18.500°E / 35.933; 18.500, 195 nautical miles (361 km; 224 mi) east of Malta.

[23] UB-47's next success came a week later, on 11 October, when the 5,002 GRT British steamer Crosshill was sunk west of Malta with the loss of four men.

[25] A German military announcement of 20 October proclaiming Steinbauer's sinking of the ship reported that Crosshill's cargo included horses and Serbian grooms.

[29] UB-47's tally of sunken ships for the month of October came to 24,776 gross register tons, which accounted for nearly 20% of the total sunk by all German U-boats in the Mediterranean.

[31] Although it was screened by light cruisers and naval trawlers,[31] Steinbauer was, nonetheless, able to sink the 11,100-ton displacement ship east of Cerigo.

[36] The 8,826 GRT Huntsend was the former North German Lloyd liner Lützow, which had been captured by British naval forces in the Mediterranean in August 1914,[37] and, like UB-47, had been built by AG Weser in Bremen.

[38][Note 5] On 1 March 1917, UB-47 torpedoed and damaged the British steamer Euterpe near Suda Bay, killing two men in the process.

[39] A week later, on 8 March, Steinbauer sank his last ship at the helm of UB-47, when Georgian was sent to the bottom 52 nautical miles (96 km; 60 mi) from Cape Sidero.

The 1890 British ship, rated at 5,088 gross register tons, was carrying government stores; five of her crew perished in the attack.

[42][43] Nestos was carrying a load of wheat from New York for Piraeus when shelled and sunk 50 nautical miles (93 km; 58 mi) from Sapientza.

[4] U-47's first success in Austro-Hungarian service came nearly six months later when, on 12 January 1918, Molitor torpedoed the French steamer Mica from Saigon just short of her destination of Milos.