On the evening of 18 June 1918, Unit F was on an antisubmarine patrol in the Strait of Otranto when it became involved in a friendly fire incident. At 21:00, the submarine chasers′ hydrophones detected sounds which their crews assumed were coming from a submarine. The submarine chasers followed the sounds until 22:40, when they grew louder and the submarine chaser crews interpreted them as coming from a submarine on the surface. All three submarine chasers headed toward the source of the sound at flank speed and soon sighted the Royal NavydestroyersHMS Defender and HMS Nymphe, identifying them merely as two low-lying objects in the water which the submarine chaser crews believed were Central Powers submarines. The submarine chasers challenged the British destroyers with recognition signals flashed several times by blinker light. Defender and Nymphe did not respond, so the submarine chasers opened fire, with SC-94 firing two rounds and SC-151 firing one. One of SC-94′s shots hit Nymphe, severing a steam line and putting one of her steam engines out of commission. Defender and Nymphe immediately flashed lights at the submarine chasers, which ceased fire, went alongside the destroyers, and discovered their identities. When the submarine chaser crews asked why the destroyers had not answered the recognition signals, the crews of Defender and Nymphe replied that they had orders not to use recognition signals, a restriction unknown to the submarine chaser crews because of a lack of a unified Allied command in the area. Defender took Nymphe in tow, and the submarine chasers resumed their antisubmarine patrol. Discussing the incident in a letter to the British Admiralty, the commander of United States Naval Forces Operating in European Waters, Vice AdmiralWilliam Sims, wrote: "While it appears that, under attendant circumstances, the commanding officers of the submarine chasers were justified in opening fire on the destroyers, I nevertheless wish to express regret that the incident occurred, and that H.M.S. Nymphe should have sustained damage."[3]
Beginning at 11:30 on 19 June 1919, Unit F and Unit G (made up of USS S.C. 95, USS S.C. 179, and USS S.C. 338) gained and lost sound contact on a submarine several times before Unit G finally attacked it with 16 depth charges at 40°24′N019°00′E / 40.400°N 19.000°E / 40.400; 19.000. After the attack, Unit G again made sound contact on the submarine, indicating that it had survived, but Unit G′s submarine chasers had expended all of their depth charges and therefore discontinued pursuit of it.[4]
By late October 1918, Austria-Hungary had begun to disintegrate, and its dissolution led to a requirement for Allied forces to maintain order along the Adriatic coast of what had been Austria-Hungary. As a result, on 15 November 1918, Unit F received orders to proceed to the island of Lissa in the Adriatic.[5]
Not long afterward, SC-94 was decommissioned. She was sold in Italy in early 1919.[1][6]
When the U.S. Navy adopted its modern hull number system on 17 July 1920, Submarine Chaser No. 209 retrospectively was classified as SC-209 and her name was shortened to USS SC-209.
Woofenden, Todd A. Hunters of the Steel Sharks: The Submarine Chasers of World War I. Bowdoinham, Maine: Signal Light Books, 2006. ISBN978-0-9789192-0-7.
