Owned by A/S Ørnen and managed by A/S Thor Dahl of Sandefjord. She had been purchased in 1928 and converted from an oil tanker. She was 12,201 gross tons, 7272 net tons, 16,500 deadweight tons, 527.1 feet registered length, 66.75 inches breadth, 33.9 feet draught, and 42.1 feet registered depth. She was fitted with a quadruple-expansion four-cylinder steam engine of 787 nominal horsepower, had a speed of 10 knots and carried about 2000 tons of fuel oil. As the 16,203 tons deadweight tanker San Lorenzo, she was launched by Swan, Hunter & Wigham Richardson Ltd, Wallsend, River Tyne, on 27 December 1913, and was delivered to her owners Eagle Oil Transport Co Ltd, London, on 10 February 1914. During the First World War she was employed as a naval base fleet oiler.

On 3 June 1917 she was torpedoed by the German submarine U54 about 140 miles off northwest Ireland. The submarine reported that about 1700 hours on that day a convoy of two tankers escorted by armed trawlers was sighted by periscope proceeding on a westerly course; U54 surfaced and pursued the ships and at 2145 hours dived for a submerged attack on the leading tanker. Both tankers were carrying out a zig-zag course and it was not until 2300 hours that U54 was able to fire a torpedo, at a range of 560 metres, and this hit the leading tanker, which was San Lorenzo. Another German submarine, U70, was in the vicinity and witness the attack. U54 surfaced shortly after midnight and observed that the tanker was stopped, but on an even keel, with two armed trawlers standing by. When U54 returned for a daybreak attack shortly before 0500 hours on 4 June, the tanker had gone and was presumed sunk. But despite having extensive damage, San Lorenzo was able to get to port safely and was repaired.

On 14 September 1928 San Lorenzo was sold to Thor Dahl, converted into a whale factory, and renamed Ole Wegger.