Laid down as Fort McHenry for US Shipping Board (USSB), completed in August 1922 for Bethlehem Shipbuilding Corp, Baltimore MD. In April 1924 renamed Vacoil for Vacuum Oil Co Inc, New York. In January 1929 renamed Schulau and registered in Germany for Deutsche Vacuum Oel AG, Hamburg. In February 1935 sold to Britain and renamed Eocene for Standard Transportation Co Ltd, Hong Kong. 1941 transferred to Ministry of War Transport (MoWT).

At 20.19 hours on 20 May 1942 the Eocene (Master Henry W. Wilcox) in convoy AT-46 was hit by one of two torpedoes from U-431 about 13 miles northeast of Bardia. The tanker was the leading ship of the port column in station #11 and struck by the torpedo on the starboard side between #1 and #2 tanks. The explosion badly bulged and buckled the well deck and completely wrecked the forward part of the bridge with all port holes blown in. Miraculously the highly flammable cargo in the forward tanks did not catch fire but was seen to pour out in a thick stream through the hole in the side. The ship immediately began to settle by the head with a list to starboard. A haze of benzine fumes enveloped the tanker and the master ordered the crew to abandon ship due to the danger of an explosion or being gassed by the fumes. The two lifeboats aft were lowered in a moderate swell with the officers and engineers leaving last after about 25 minutes. Eocene was still settling slowly when a minor explosion occurred at 21.26 hours, presumably caused by fumes reaching the boiler fires in the engine room. The back of the ship broke, being weakened from previous bomb damage that had only been temporarily repaired. There were no casualties and all hands were picked up by HMS Cocker (T/Lt J. Scott, RNVR) within one hour after the attack. The armed whaler stood by the wreck which remained on an even keel until she sank vertically by the bow with the stern raising into the air at 23.45 hours. The master, 33 crew members, six gunners (the ship armed with one Italian 76mm gun, two 20mm, four machine guns), two army engineers and one convoy signalman were landed at Tobruk on the morning of 21 May.