Wrecks over 100 years old and archaeological objects found underwater are protected under the National Monuments (Amendment) Acts 1987 and 1994. Significant wrecks less that 100 years old can be designated by Underwater Heritage Order (UHO) on account of their historical, archaeological or artistic importance as is the case with the wreck of the RMS Lusitania lost off the Old Head of Kinsale in 1915. UHOs can also be used to designate areas of seabed or land covered by water to more clearly define and protect wreck sites and archaeological objects . https://www.archaeology.ie/underwater-archaeology
On the 24th of May, 1917, USS O’Brien arrived in Queenstown (now Cobh) in the south of Ireland. O’Brien was in the company of the other US Destroyers Benham, Cummings, Cushing ,Nicholson, Sampson and Rowan. Queenstown was the centre for anti-submarine forces, on the Western Approaches, under the command of Admiral Lewis Bayley, Commander in Chief , Coast of Ireland. Initially there was uncertainty as to the most effective use of destroyers. At first they were given patrol areas which they would scout, singly or in pairs. Any stray incoming merchantmen seen, were to be escorted to near their destinations. This was a most ineffective use of the force, as the chances of coming across, and destroying a lone submarine in the vastness of the Western Approaches was virtually nil.
By Summer 1917, under the urging of commanders such as Admiral Sims, Commander of US Naval Forces in Europe, the convoy system was initiated. Groups of merchantmen were escorted through the war zone by flanking destroyer screens. This had the dual effect of reducing the amount of targets for German u-boats, and allowing destroyers and sloops to attack the harassing submarines. The priorities of the destroyers were to:
Protect and escort Merchantmen.
Save the crews and passengers of torpedoed ships.
Anti-submarine patrols did continue also for the duration of the war, especially in the Irish Sea and close to the coast of France, where u-boats would try to sink merchantmen as the convoys dispersed. In 1918, any destroyer in the Irish Sea, which was not actively convoying, came under the orders of The Irish Sea Hunting Flotilla, under the command of Captain Gordon Campbell VC based in Holyhead, Wales. US destroyers were also used to patrol the west coast of Ireland to hunt suspected gun-running ships, for Irish Republicans.
The destroyers , initially, were ill-equipped to fight submerged submarines. When they arrived in Europe they were armed with guns and torpedoes. The only undersea weapons supplied were single hand-launched 50lb depth charges which were particularly ineffective. It was the later fitting of dual depth charge racks on the sterns of the ships, Thornycroft depth charge throwers, and Y shaped charge throwers that turned them into a dangerous force. These were capable of dropping and firing a continuous patterned barrage of 200lb, charges around a submarine's suspected position. Most of the retro-fitting of these armaments was done at Cammel Laird in Birkenhead, England.
On the 7th of June, 1917, in position 52.44N, 14.15W, SS Cranmore was torpedoed while under escort. Ship continued under her own steam. USS O’Brien escorting until relieved by British sloop HMS Camellia who escorted her to Galway.
On the 16th of June, 1917,4.30pm, in position 10 miles south of Ballycotton, USS O’Brien sighted periscope and dropped depth charge. At 7.30pm the British sloop HMS Jessamine reported passing through large area of oil in same position.
On the 7th of July, 1917, USS O’Brien picked up survivors of Norwegian ship SS Victoria ll, in position 48.26N, 05.26W. This ship had been shelled by enemy submarine on the 7th of July. Some of the enemy crew boarded the ship and stripped her of any foodstuffs and portable equipment. The ship’s crew were sent to the boats, and shortly afterwards the Victoria ll was sunk by explosives placed on board.
In the week of the 21st of July, 1917, USS Porter, USS Nicholson, USS Cassin, USS Ericsson, and USS O’Brien returned from convoy duty in France. The latter two ships escorting to Queenstown USS Kanawha.
On the 20th of August, 1917, USS O’Brien received signal from sloop HMS Camelia, reporting submarine sighted. O’Brien and Nicholson raced to the spot, but nothing further seen. Later that day, O’Brien made two submarine sightings, but no attack was made, due to inability to pinpoint position of submarine.
On the 3rd of September, 1917, in pos 49.10N, 10.33W USS O'Brien sighted submarine on surface.
On the 14th of September, 1917, in pos 50.37N, 08.20W, USS O’Brien sighted enemy submarine which submerged immediately.
On the 16th of September, 1917, in pos 49.14N, 10.52W, the French fishing vessel Quatrefreres was sunk by gunfire. USS O’Brien picked up 6 survivors, who were landed at Queenstown.
On the 15th of Decmber, 1917, USS O’Brien,and Parker were on anti-submarine patrol. When in a postion 15 miles WSW from the Smalls, O’Brien sighted conning tower of submarine . O’Brien gave chase and was joined by USS Wilkes and Parker. Submarine submerged and was not seen again. Until later when trawler Okino reported submarine on surface. USS O’Brien went to area and sighted steamer being torpedoed. This was the Q-Ship HMS Arbutus.
O, Brien approached the sticken ship and spotting periscope, dropped one depth charge. This charge did not explode, and attack was ended.. USS Wilkes and Parker approached, and screened ships. USS O’Brien took on board 5 officers and 76 men from the Arbutus.
USS O’Brien delivered the rescued crew of HMS Arbutus, some of who were seriously injured, safely to Milford Haven.
On the 22nd of January, 1918,USS Balch, Davis, Wadsworth, O’Brien and Parker escorted submarine tender USS Bushnell, and 6 United States submarines from position 50.00N, 15.00 W, to Queenstown
On the 3rd of February, 1918, USS O’Brien, and Cummings, safely escorted SS Philadelphia, from position 48.40N, 15.00W, to Liverpool.
On the 7th of May, 1918, in pos 52.44N, 05.33W, USS OBrien sighted periscope. Dropped 21 depth charges. Heavy oil came to surface.
On the 12th of May, 1918, in pos 49.37N, 5.01W USS Davis and USS O'Brien sighted oil wake. The destroyers dropped 40 depth charges. More oil came to surface.
On the 16th of May, 1918, in pos 51.40N, 07.40W, USS O'Brien sighted submarine. USS Allen and USS Beale came to assist. Together they dropped 24 depth charges. No apparent result.
In June, 1918, USS O’Brien was transferred to the Brest, France, command. She served here for the remainder of the War.