Except for a voyage to Halifax, Nova Scotia, she served along the East Coast until 9 January 1918, when she was assigned to the Naval Overseas Transportation Service.

She made an unscheduled stop in Barbados because the water level was over the Plimsoll line, indicating that it was overloaded,[1] but investigations in Rio proved the ship had been loaded and secured properly.

[16] As Cyclops disappeared during World War I, and submarines of the Imperial German Navy were known to operate in the West Indies, that the ship was lost due to hostile action was considered.

[1] Reports indicate that on 10 March, the day after Cyclops was rumored to have been sighted by Amolco, a violent storm swept through the Virginia Capes area.

While some suggest that the combination of the overloaded condition, engine trouble, and bad weather may have conspired to sink Cyclops,[1] an extensive naval investigation concluded: "Many theories have been advanced, but none that satisfactorily accounts for her disappearance.

"[5] This summation was written, however, before two of Cyclops's sister ships, Proteus and Nereus, vanished at sea during World War II less than a year after their sale to civilian operators.

In both cases, their loss was theorized to have been the result of catastrophic structural failure,[18] but a more outlandish theory attributes all three vessels' disappearances to the Bermuda Triangle.

This was observed definitively on USS Jason, and is believed to have contributed to the sinking of another similar freighter, Chuky, which snapped in two in calm seas.

[21] Investigations by the Office of Naval Intelligence revealed that Captain Worley was born Johan Frederick Wichmann in Sandstedt, Hanover, Germany in 1862 (the official Navy Register lists his date of birth as 11 December 1865), and that he had entered North America by jumping ship in San Francisco in 1878.

He would berate and curse officers and men for minor offenses, sometimes getting violent; at one point, he had allegedly chased an ensign about the ship with a pistol.

In Rio de Janeiro, one such man was assigned to oversee the loading of manganese ore, something a collier was not used to carrying, and in this instance the ship may have been overloaded, which may have contributed to her sinking.

One of the passengers on the final voyage was Alfred Louis Moreau Gottschalk, the consul-general in Rio de Janeiro, who was as roundly hated for his pro-German sympathies, as was Worley.

Charles Winfield Reed, the game's protagonist, served on the USS Cyclops as a sailor and diver before her mysterious sinking, of which he is the sole survivor.

The ship's sinking and Reed's subsequent experiences prior to the game's beginning also closely mirror that of the unnamed protagonist of the H. P. Lovecraft short story "Dagon."