[1][2] In 1920 Anglo-Saxon Petroleum Co., a wholly-owned subsidiary of the Royal Dutch Shell Company, decided to expand their oil carrying fleet by placing orders with a number of United States West Coast shipyards.

In August 1920 it was reported that one such order for three tankers of approximately 8,400 deadweight tonnage each was entered with the Southwestern Shipbuilding & Drydock Co.[3] Silvanus was the second of these three vessels (the other two being SS Scopas and SS Semiramis), and had her keel laid at the shipbuilder's yard on 20 October 1920, and launched on 30 June 1921, with Mrs. Earl L. Miller, wife of the Pacific coast manager of the Royal Dutch Shell, being the sponsor.

[6] Upon undergoing her final inspection, and loading the cargo, Silvanus departed San Francisco on 31 August, bound for Shanghai.

[8] The tanker then proceeded to visit ports of Shanghai, Singapore and Balikpapan, and returned to San Francisco on 12 December via Victoria and Seattle, thus successfully completing her maiden voyage.

[11] After discharging her cargo, the tanker departed on 14 March for Balikpapan, the major oil producing center in the Dutch East Indies.

[13] Subsequently, Silvanus spent the remainder of 1922 transporting fuel oil between Abadan and Suez, before departing in early January 1923 back to Singapore and Balikpapan.