USS Big Horn ( AO - 45 ) USS " Big Horn " ( AO - 45 / IX - 207 ) was a Q - ship of the United States Navy named for the Bighorn River of Wyoming and Montana . " Gulf Dawn " , a single - screw oil tanker , was built in 1936 at Chester , Pennsylvania , by the Sun Shipbuilding & Drydock Corp . and operated by the Gulf Oil Corporation . Acquired by the Navy on 31 March 1942 , she was renamed " Big Horn " and given the hull designation symbol AO - 45 on 3 April 1942 . Her conversion began at the Bethlehem Shipyard in Brooklyn , New York . She was commissioned 15 April 1942 , under the command of Commander James A . Gainard , USNR , formerly master of SS " City of Flint " , which had become the center of an international incident at the beginning of the war , and was later sunk by a U - boat . Atlantic Fleet . Sailing to Boston on 23 April , " Big Horn " entered the Boston Navy Yard for conversion to a Q - ship . A disguised heavily - armed merchantman , the decoy ship was intended to lure unsuspecting U - boats to the surface and sink them with gunfire . While at Boston , " Big Horn " completed her disguise as a fleet oiler and was given extra watertight integrity – in case she was torpedoed – by the installation of thousands of sealed empty drums in her cargo tanks . That work was completed on 22 July 1942 . After two days on the degauss ing range and in calibrating compasses and radio direction finders , " Big Horn " proceeded to Casco Bay for training under Commander , Destroyers , Atlantic Fleet . This training period was followed by a shakedown cruise which was completed on 26 August 1942 , at which date USS " Big Horn " put in again at the Navy Yard , Boston , for further alterations and repairs until 12 September . As U - boats had been attacking bauxite ore cargo ships in the West Indies , the Q - ship sailed south to help defend the convoy routes there on 27 August . 1942 . The first cruise of USS " Big Horn " began on 27 September 1942 , when the ship proceeded from New York with a convoy bound for Guantanamo Bay , Cuba , taking a position which permitted the vessel to act as a straggler . The trip was made without incident , and thereafter " Big Horn " was semi - attached to NOB [ Naval Operating Base ] Trinidad , with orders to operate from that base over the bauxite route to and from ports where that commodity was loaded . Many ships in this area had been sunk in recent weeks . Ships proceeding from Trinidad were convoyed to a designated point from which they fanned out to take various routes to their ultimate destination . " Big Horn " was directed to proceed to that point and drop down on independent routes to and from bauxite ports . After joining south - bound convoy GAT - 11 at Guantanamo Bay , the ship – using her old call sign of " Gulf Dawn " — purposefully lagged behind the convoy en route to Trinidad . No U - boats were tempted to attack , however , and the ship moored in Port of Spain on 9 October . On 16 October 1942 , " Big Horn " sailed in convoy T - 19 from Trinidad to the point of separation . That same afternoon , three U - boat s attacked the convoy , and at 15 : 20 in , the British steamer SS " Castle Harbour " was hit on the starboard side by a torpedo and sank in less than two minutes . At almost the same time the United States steamer , coal - laden , was struck forward on the starboard side . Later she limped into Trinidad . Soon afterwards , lookouts on " Big Horn " sighted a U - boat moving at periscope depth on the port beam , but in such a position that no action could be taken without damaging the United States troopship " Mexico " or the Egyptian ship " Raz El Farog " . At 16 : 27 , lookouts on " Big Horn " again sighted a periscope and conning tower , on the port side , and her four - inch ( 100 mm ) gun was trained in that direction just as a submarine chaser crossed through the line of fire and dropped five depth charge s . Thereafter , the cruise in these waters was continued without incident for several days and " Big Horn " returned to NOB Trinidad about 29 October . A second cruise in company with a convoy from Trinidad was begun by " Big Horn " on 1 November 1942 , to a point nearly due north of Paramaribo , where the vessel left the convoy and proceeded on varying courses without incident until return to Trinidad on 8 November 1942 . On 10 November 1942 , USS " Big Horn " sailed in convoy TAG - 20 , with the gunboat USS " Erie " ( PG - 50 ) , two PC - boats ( submarine chaser s ) , and a PG - boat ( patrol gunboat ) acting as escorts . Because of submarine warnings , the convoy changed course so that the approach to Curaçao was made from the south and west . Because of engine difficulties , USS " Big Horn " dropped out of the convoy at 15 : 30 on 12 November 1942 , in company with a Venezuelan tanker , and arrived at a point about 1 . 5 miles ( 3 km ) off Willemstad harbor , where the Curaçao - Aruba subsidiary convoys were joining the main convoy . At 17 : 02 , a great volume of smoke was sighted as it rose from " Erie " ’ s stern , about 1000 yards ( 1000 m ) on the starboard bow of " Big Horn " , at . " Erie " had been torpedoed on the starboard side aft . " Big Horn " called General Quarters , increased speed to and proceeded for the scene of action , but repeated orders from Willemstad forced " Big Horn " to alter course at 17 : 25 and proceed to Willemstad . " Erie " swung into the wind ; efforts to subdue the fire were unsuccessful . The gunboat was finally beached , officers and crew abandoning ship . On 21 November 1942 , USS " Big Horn " proceeded from Curaçao with a convoy bound for New York , The convoy proceeded on a course for Guantánamo with a Dutch gunboat and four SC - boats as escorts . Other vessels joined convoy at Guantánamo until on leaving that meeting point there were 45 ships and five escorts in company . The remainder of the cruise to New York via Caicos Passage was uneventful , and " Big Horn " anchored in The Narrows in New York Harbor at 20 : 40 on 1 December 1942 . During the next few weeks , " Big Horn " entered the Todd Shipyard at Hoboken , New Jersey , for what proved to be nine weeks of repair work and alterations . The latter included the installation of a mousetrap , a hedgehog depth charge projector , and a DF ( direction finding ) radio receiver . 1943 . She departed New York on 17 February 1943 , and arrived at New London , Connecticut , the following day . On 19 February 1942 , Lieutenant Commander Farley assumed command of a newly organized Task Group consisting of " Big Horn " and three 173 - foot ( 53 m ) PC - boats : " PC - 560 " , " PC - 617 " , and " PC - 618 " . Antisubmarine measures had been so successful that no vessels had been sunk in coastal waters since July 1942 . This Task Group was designed to hunt U - boats in the central Atlantic ; the three PC - boats would escort " Big Horn " , which would act as bait and support in antisubmarine combat , as well as fuel and supply ship for the escorts . During the period from 2 to 14 March , this Task Group conducted training exercises in Long Island Sound with the submarine " Mingo " ( SS - 261 ) supplied for the purpose by ComSubLant , During the next two weeks the Task Group made a shakedown cruise . After a short trip to New York between 20 and 28 March , the Task Group continued antisubmarine training against " Muskallunge " ( SS - 262 ) until 9 April . " Big Horn " and the two subchasers then sailed south in Task Group 21 . 8 ( TG 21 . 8 ) to New York , arriving there on 9 April . Convoy UGS - 7A sailed on the morning of 14 April 1943 , and the special Task Group joined up off New York and continued in company until 08 : 00 on 21 April , when the Group left the convoy and dropped astern 25 nautical miles ( 45 km ) , proceeding as straggler - with - escorts , although the escorts remained far enough astern so that they would not be visible to an enemy submarine sighting " Big Horn " . The cruise was uneventful during the next two weeks . After several changes of course , " Big Horn " was at ( about 500 miles ( 900 km ) south of the Azores ) at noon of 3 May 1943 . Early that morning , " Big Horn " had made radar contact with a suspected U - boat at a range of about six miles ( 11 km ) and sent the two PCs to investigate . At 11 : 04 , " PC - 618 " reported a submarine on the surface , distant about six miles ( 11 km ) . At 12 : 35 , " Big Horn " got a sound contact and delivered a hedgehog attack just after sighting a periscope on the starboard bow at 12 : 42 , followed by a heavy swirl as the U - boat dove . At 13 : 33 a second attack was delivered and the contact was lost . At 15 : 40 the contact was regained at 3 , 700 yards ( 3 . 4 km ) and at 15 : 54 , speed five knots ( 9 km / h ) , " Big Horn " delivered a third attack . About five of the hedgehog projectiles ( which detonate only on contact ) exploded about 12 seconds after they entered the water , and " Big Horn " continued in to drop depth charge s . Considerable light oil came to the surface and continued to spread for two hours . At 01 : 03 on 4 May an oil patch was visible over an area of 200 to 300 yards ( about 200 m ) . By daylight that morning , all traces of the oil slick were gone . As none of the vessels in the Group were able to establish contact during the next 44 hours , it was presumed that one submarine had been destroyed ; that the other U - boat which had been sighted by the " PC - 618 " had moved out of the area . A postwar review of German U - boat losses , however , indicated that no submarines were sunk on that date in this area . Continuing on a homeward course , the Commanding Officer of " Big Horn " attempted to use the COMINCH ( Commander in Chief , United States Fleet ) daily submarine estimates as guides for fruitful changes of course , but after several attempts had failed to produce results , the Task Group Commander recorded in his log , on 13 May 1943 : This makes three submarines we have attempted to intercept on our return trip , all of which we theoretically should have met . This experience again accents the hopelessness of trying to find submarines . The proper procedure , as originally planned , is to remain in the vicinity of convoys , to which the submarines will come . On the next trip , it is planned to stay within about 15 miles [ 28 km ] , or less , of the convoy After returning to New York on 17 May , the ship underwent another overhaul between 19 May and 16 July . On her final cruise as a Q - ship , " Big Horn " again she served as the flagship of a small Task Group which included only two other vessels : " PC - 618 " and " PC - 617 " . Commander L . C . Farley had relieved Captain Gainard as Commanding Officer of " Big Horn " on 24 June because of the illness of the latter . The Task Group departed New York on 20 July 1943 , and proceeded to Norfolk , where convoy UGS - 13 made up and sailed on the morning of 27 July . On 29 July , " Big Horn " straggled from the convoy and streamed her Mark 29 gear . For the next few days she trailed the convoy , distant about fifty miles ( 90 km ) . On 4 August , U - boats were reported by COMINCH to be operating in the vicinity of 38°N , 38°W , and the Task Group changed course to intercept . On 6 August , a submarine was sighted in and attacked by " PC - 618 " with mousetraps which failed to explode . Thereafter the contact was not regained . An expanding box search was carried out during the next few days without results , then the group moved northward of the Azores . Planes from the escort aircraft carrier USS " Card " ( CVE - 11 ) were sighted several times during this period and it later transpired that some of these planes had made definite kills of U - boats during that period . " Big Horn " was not so fortunate , in spite of frequent changes of course to intercept submarines reported by COMINCH . The cruise continued in the general area and as far south as the latitude of Dakar , during the last weeks of August and throughout September . During the last week of September , a new search area was tried far to the north of the Azores , but again without success ; then the homeward leg of the cruise was executed without event . " Big Horn " and her escorts stood up Ambrose Channel on 7 October 1943 . On 14 October , COMINCH directed that " Big Horn " should be retained in active service but that no alterations or extensive repairs should be made without specific authorization of COMINCH . After training exercises in the New London area with a friendly sub from 29 October through 10 November , " Big Horn " made one more uneventful cruise in company with " PC - 617 " and " PC - 618 " . On 11 November , the Task Group returned to New York to refuel and provision ; on 15 November , the Task Group departed in company and proceeded on an eastward course until they had reached the hunting ground north of the Azores on 27 November . Searches were unsuccessful . " Big Horn " then steamed back to New London on 30 November , whence she conducted training in Long Island Sound , before departing on a third " decoy " cruise on 19 December . Although she operated near a suspected U - boat concentration in the waters off Bermuda , the Q - ship and her two subchasers had no contacts and returned to New York empty - handed on 30 December . In summarizing this cruise , the Commanding Officer of " Big Horn " wrote It may be noted that during the period from 27 November to 1 December , this Task Group was in the midst of a group of from 10 to 15 U - boats . Nine contacts , sightings or attacks on U - boats took place in our immediate vicinity , so that it is most unlikely that we were not seen by some U - boats . Evidently the U - boats are wary of attacking an independent tanker . If the Q - ship program has contributed to this wariness , as is suggested in several prisoner - of - war statements , many independent merchant ships may thereby have escaped attack , and the Q - ship program has thus been of value . Coast Guard , 1944 . COMINCH did not agree , and , considering similarly meager results and even losses by other Q - ships , cancelled the entire Q - ship program . " Big Horn " was ordered to Boston , and arriving there on 17 January 1944 , was transferred to the United States Coast Guard as USCGC " Big Horn " ( WAO - 124 ) to join " Asterion " ( AK - 100 ) on weather - patrol duty in the North Atlantic , under the supervision of the United States Coast Guard and manned by Coast Guard officers and crew . The ship was assigned to the 1st Naval District and operated out of Boston . Her main duty was to conduct 25 - day patrols on the Coast Guard ' s mid - ocean weather stations and report on surface and aerial weather conditions . These reports were used to determine air - ferry routes across the Atlantic and to reroute shipping around storm concentrations . Because her antisubmarine equipment still remained intact , she could take offensive action if such opportunities presented themselves . Her name was struck from the Naval Vessel Register on 22 January 1944 . Pacific Fleet , 1945 . Although she kept her Coast Guard crew , " Big Horn " was returned to Navy control on 1 February 1945 and redesignated IX - 207 two days later . Over the next five weeks , the ship was converted into an oil shuttle and storage vessel before departing for the Pacific on 11 March . After loading 84 , 000 barrels ( 13 , 400 m³ ) of oil at Aruba , Netherlands West Indies , on the 18th , she passed through the Panama Canal on 21 March and reported to the Service Force , Pacific Fleet , that same day . Steaming west , " Big Horn " stopped at Pearl Harbor in early April before sailing on to the Marshall Islands , where she anchored at Ulithi on 1 May . Assigned to Service Squadron 10 ( ServRon 10 ) , the shuttle tanker carried oil to Kossol Roads and Peleliu in the Western Carolines in early May before moving on to Tacloban in the Philippines later in the month . Returning to Ulithi on 3 June , she loaded more oil and delivered it to Leyte on the 9th . Over the next eight weeks , " Big Horn " carried out three more of these shuttle missions from Ulithi to Leyte . The tanker sailed to Okinawa on 11 August and she was at that island on 15 August 1945 , when her crew heard the news of the Japanese surrender . Departing Okinawa on 29 September , " Big Horn " steamed to Japan , where she was assigned duty as a station tanker at Nagoya on 3 October . She remained there through January 1946 . After transferring her cargo of oil to " Beagle " ( IX - 112 ) , the shuttle tanker got underway for home on 25 February . After a refueling stop at Pearl Harbor , she passed through the Panama Canal in early April and moored at Mobile , Alabama , on 15 April . " Big Horn " then proceeded to New Orleans , Louisiana . She was decommissioned on 6 May 1946 , and her name was struck from the Naval Vessel Register on 3 July 1946 . Berthed at Orange , Texas , the ship was subsequently delivered to the Maritime Commission for disposal on 22 November 1946 .