The United States Navy suffered its largest non-combat loss of life when the collier USS Cyclops set sail from Barbados to Baltimore and was never seen again, presumably disappearing in the Bermuda Triangle.

The United States Navy (USN) is the maritime service branch of the United States Department of Defense. It is the world's most powerful navy with the largest displacement, at 4.5 million tons in 2021. It has the world's largest aircraft carrier fleet, with eleven in service, one undergoing trials, two new carriers under construction, and six other carriers planned as of 2024. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the U.S. Navy is the third largest of the United States military service branches in terms of personnel. It has 299 deployable combat vessels and about 4,012 operational aircraft as of 18 July 2023. The U.S. Navy is one of six armed forces of the United States and one of eight uniformed services of the United States.

A collier is a bulk cargo ship designed or used to carry coal. Early evidence of coal being transported by sea includes use of coal in London in 1306. In the fourteenth and fifteenth centuries, coal was shipped from the River Tyne to London and other destinations. Other ports also exported coal – for instance the Old Quay in Whitehaven harbour was built in 1634 for the loading of coal. London became highly reliant on the delivery of coal by sea – Samuel Pepys expressed concern in the winter of 1666–67 that war with the Dutch would prevent a fleet of 200 colliers getting through. In 1795, 4,395 cargoes of coal were delivered to London. By 1824, this number had risen to about 7,000; by 1839, it was over 9,000. The trade continued to the end of the twentieth century, with the last cargo of coal leaving the Port of Tyne in February, 2021.

USS Cyclops (AC-4) was the second of four Proteus-class colliers built for the United States Navy several years before World War I. Named after the Cyclops, a race of giants from Greek mythology, she was the second U.S. naval vessel to bear the name. The loss of the ship and 306 crew and passengers without a trace occurred sometime after 4 March 1918.