He and his family, including his son Harry, used her in waters ranging from the North Sea to the Dutch East Indies.

On 18 August, before her conversion into a warship was complete, Captain Thomas P Magruder, the Commander of Squadron Four, Patrol Force, raised his burgee pennant aboard her to maker his flagship.

A week later, Wakiva II left Boston for Provincetown, Massachusetts with Squadron Four, which included six French Navy submarine chasers and several patrol boats and converted fishing craft.

Nine days later, Captain Magruder hauled down his pennant from Wakiva II to establish his headquarters ashore.

On 28 October 1917, Wakiva II and USS Alcedo rescued survivors from the troopship Finland, which had been disabled by a torpedo.

[4] On 23 November 1917, Wakiva II sighted an object at 500 yards (460 m) range that they took to be a U-boat conning tower.

After firing seven rounds, Wakiva II got close enough for her crew to see that the object was a convincingly-painted dummy for target practice.

[4] As soon as they rejoined the convoy, Noma sounded the alarm and launched a depth charge at what her crew believed to be a U-boat.

While still 1+1⁄2 nautical miles (3 km) from Nova, Wakiva II sighted a periscope at a range of 100 yards (91 m).

[4] As Wakiva II passed over the suspected U-boat a second time, she launched a salvo of depth charges.

[4] In his action report after the engagement, Wakiva II's commanding officer praised his crew as a "perfect fighting unit" that showed "admirable coolness and courage", and did not manifest any nervousness or inefficiency.

Momentarily she had to suspend fire, to avoid hitting the USSB cargo ship Florence H., which was just beyond where the U-boat had appeared.

The armed yacht Noma signalled the convoy commodore aboard the troopship USS Black Arrow to this effect.

Electrician Second Class Charles E. Kirkpatrick, UNSRF, was on duty as Wakiva II's wireless telegraphist.

Chief Boatswain's Mate Thomas Olson, USNRF, rigged out the motor whaleboat and rousted out men from below decks.

As the engine room flooded, Machinist Mate First Class Charles AA Smith began to start her pumps, then realised that they could not cope with the rate at which water was entering the hull.