Artemis was armed with guns and depth charges and sent to Europe as a patrol craft to protect Allied ships from German submarines and other dangers.

Cristina was a steel-hulled steam yacht designed by naval architects Gielow and Orr and built at Wilmington, Delaware by Pusey and Jones Co. for Frederick C. Fletcher of Boston, Massachusetts.

[8][note 3] After the U.S. entered World War I in the spring of 1917, the Navy, in its wide-ranging search for ships suitable to serve as patrol craft, purchased Artemis early that summer for $181,300.

After visiting Artemis at Shewan's Shipyard, Brooklyn, New York, he reported her to be a "good, well-built, apparently seaworthy boat ..." and recommended that her conversion work be expedited.

[3] Over the next week, Artemis remained at the Shewan yard, undergoing the modifications necessary to convert her from a peacetime cruising yacht to a diminutive man-of-war – such alterations as the installation of gun mounts and magazines, the fitting-out quarters for officers and men, and the overhauling of her boilers and machinery.

[3] Artemis' initial mission was a part in the operation of towing ten 110 ft (34 m) subchasers – built in American boatyards for the French government – from New York City to Leixoes, Portugal.

[3] May and Wenonah left the column on 21 November to search for Druid and the French subchasers; and, the following day, Artemis cast off from Hannibal and took under tow her former charge, SC-65.

McCully, the squadron commander, embarked in May and directed Artemis – battered by the storm – to put into Gibraltar for repairs, and she arrived there on 26 December 1917.

[3] Over the next month, Artemis underwent voyage repairs before she again stood out to sea on 28 January 1918 to serve as part of the escort for a convoy then forming up for Bizerte, Tunisia.

The next day at 14:50, while Artemis was steaming on the left wing of the formation, an enemy submarine torpedoed the convoy guide, SS Maizar, striking the merchantman's port side, forward of her bridge.

The next afternoon, another merchantman, SS Tenterton, sounded the submarine alarm, and Artemis spent almost an hour at general quarters, searching for the supposed submersible before securing it at 15:10, empty-handed.

On 1 May, as Artemis was proceeding toward rendezvous with an American merchantman off Cartagena, Spain, she spotted two suspicious-looking submarines—escorted by a torpedo boat—operating on the surface within Spanish territorial waters.

She arrived at her designated rendezvous point off Escombrera Island at 15:20 and then stood in towards the coast, carefully plotting her course so that it did not take her within the 3 mi (4.8 km) limit.

Soon thereafter, the torpedo boat commenced making "an immense smoke screen" that effectively concealed the entrance into Cartagena of the strange submersibles.

As Don Neal plodded along at 7 kn (8.1 mph; 13 km/h), her escort zig-zagged watchfully on each side of the base course and made a complete circle of her consort every half-hour.

Then, six minutes after the initial sighting, Artemis dropped a depth charge to port over bubbles and the slick water that marked the submarine's path beneath the waves.

After the resultant explosion, Artemis cautiously claimed possible destruction of the undersea craft, but postwar accounting revealed the loss of no submarine on that day.

[3] She subsequently sighted the wreckage of a large schooner (possibly an earlier submarine victim) "evidently damaged by gunfire" lying on her beam ends.

[3] Repaired, Artemis put to sea again on 28 May, but the chronic condenser casualties aborted her mission of escorting merchantman SS Ixion to Gibraltar; the yacht returned to anchorage the next day.

Still based in Gibraltar, Arcturus, over the next two months, thrice escorted the cable ship Amber to Lagos Bay, Portugal, the latter laboring on undersea lines of communication along the Portuguese coast.

[3] Arcturus spent August 1918 at Lisbon, Portugal, for repairs before she resumed operations on Gibraltar after escorting the French submarine Astree to "The Rock" on 6–7 September.

As a further variation on her regular theme of escort duty, Arcturus twice voyaged to Tangier and back, transporting Moors from Gibraltar to Morocco (10–11 September).

Returning to Gibraltar on the 16th, Arcturus weighed anchor 11 days later and headed for Lagos Bay, Portugal, in company with Amber and the tug Crucis.

[3] In the meantime, with the engineers laboring in the sloshing, rising waters below, Arcturus put over "oil bags" on the weather side to minimize the effect of the heavy seas.

Given the critical situation, Lt. Maennle mustered all hands – except those detailed to the sea anchor, radio, oil bags, and locating the leak in the engine room – at their abandon ship stations, with their life preservers on.

[3] At 13:50 on 11 November, while still at Lisbon undergoing repairs, Arcturus received word of the armistice, ending hostilities, and the admonition to naval vessels to maintain "all precautions against attack from submarines."

"[3] On 6 December, Arcturus embarked six passengers for transportation back to the U.S., and at 07:00 on the 7th, got underway for home in company with Wheeling, Surveyor, the Coast Guard cutters Yamacraw, Druid and Wenonah.

[3] Subsequently, encountering more condenser troubles occasioned by the pounding the ship was taking in the December gales, Arcturus had to be taken in tow by Surveyor on Christmas Day.

She moved to the navy yard two days later for coal and ultimately arrived at Ulmer Park Marine Basin, Brooklyn, New York, on 30 March.

Subsequently acquired by the Tropical Fruit and Steamship Company, a Honduran firm, Artemis burned and sank in the Atlantic Ocean off Key West, Florida, on 25 February 1927.