After decommissioning from the Navy on 9 August, Black Arrow proceeded to New York on the 15th, where passenger accommodations were refitted and "various minor hull and machinery repairs" completed.
She was then chartered by the USSB to the American Line, a subsidiary of International Mercantile Marine, to inaugurate a new service to Near East and Black Sea ports including Constanța, Rumania, and Constantinople, Turkey.

Black Arrow's initial voyage to the Near East was originally scheduled for departure from New York on 15 September, but was rescheduled for the 25th.
On the 23rd, a rumor circulated that the ship was being loaded with munitions bound for General Anton Denikin's White Army, then engaged in warfare with Bolshevik forces in Russia.
The U.S. State Department denied knowledge of any such shipment, while officials of both the American Line and the USSB declined to comment; however, the arms shipment to Denikin was later apparently confirmed, with the destination port given as Novorossiysk.

Black Arrow departed New York for Constantinople and other ports on 25 September, returning via Smyrna 28 December, in the process becoming the first ship to return to the United States from Constantinople since the outbreak of World War I. The ship returned with 103 passengers including American relief workers who had been stationed in Anatolia, some of whom were willing to speak of their experiences in the region, in particular, the plight of Armenians still living there who had survived the recent genocide.
One of the relief workers, a chaplain in the U.S. Army Reserve, described how the relief commission had set up a marriage bureau in Broussa to assist Armenian girls, rescued from harems since the war's end, to find husbands willing to take them; according to the chaplain, the bureau was proving quite successful.
Another of Black Arrow's passengers was an Armenian woman of letters who, after surviving many horrors, had been spared the harem experience by a compassionate Ottoman official who found her a position as a servant in his household.
Black Arrow's cargoes on this voyage included a gift of a bronze book "from the people of Bulgaria" to Mrs. Andrew Carnegie in appreciation of her late husband's philanthropy.

On 2 January, the USSB offered a number of ex-German ships in its possession for sale, including Black Arrow, on condition that they be employed on routes set by the Board.
An offer of $700,000 was eventually made by the Oriental Navigation Company, but the sale did not eventuate.
In the meantime, Black Arrow embarked on a second voyage to the Near East, with ports of call including Constantinople, Smyrna, Varna, Bulgaria, and Constanța.
Departing New York on the 21st, the ship returned via Gibraltar and Madeira, Spain, clearing the latter port 21 March
 and arriving at New York 2 April.
Her passengers on the return trip included the captain and 39 crew of the ship Natenna, an American wooden-hulled freighter built during the war which had been lost off Casablanca, Morocco, on 8 March.
Black Arrow's return cargoes included $119,000 of antique and new Persian rugs—reportedly the first such shipment to the United States since the end of the war—which were later offered at retail prices ranging from $59 to $2,250.
After decommissioning from the Navy on 9 August, Black Arrow proceeded to New York on the 15th, where passenger accommodations were refitted and "various minor hull and machinery repairs" completed. She was then chartered by the USSB to the American Line, a subsidiary of International Mercantile Marine, to inaugurate a new service to Near East and Black Sea ports including Constanța, Rumania, and Constantinople, Turkey.
Black Arrow's initial voyage to the Near East was originally scheduled for departure from New York on 15 September, but was rescheduled for the 25th. On the 23rd, a rumor circulated that the ship was being loaded with munitions bound for General Anton Denikin's White Army, then engaged in warfare with Bolshevik forces in Russia. The U.S. State Department denied knowledge of any such shipment, while officials of both the American Line and the USSB declined to comment; however, the arms shipment to Denikin was later apparently confirmed, with the destination port given as Novorossiysk.
Black Arrow departed New York for Constantinople and other ports on 25 September, returning via Smyrna 28 December, in the process becoming the first ship to return to the United States from Constantinople since the outbreak of World War I. The ship returned with 103 passengers including American relief workers who had been stationed in Anatolia, some of whom were willing to speak of their experiences in the region, in particular, the plight of Armenians still living there who had survived the recent genocide. One of the relief workers, a chaplain in the U.S. Army Reserve, described how the relief commission had set up a marriage bureau in Broussa to assist Armenian girls, rescued from harems since the war's end, to find husbands willing to take them; according to the chaplain, the bureau was proving quite successful. Another of Black Arrow's passengers was an Armenian woman of letters who, after surviving many horrors, had been spared the harem experience by a compassionate Ottoman official who found her a position as a servant in his household. Black Arrow's cargoes on this voyage included a gift of a bronze book "from the people of Bulgaria" to Mrs. Andrew Carnegie in appreciation of her late husband's philanthropy.
On 2 January, the USSB offered a number of ex-German ships in its possession for sale, including Black Arrow, on condition that they be employed on routes set by the Board. An offer of $700,000 was eventually made by the Oriental Navigation Company, but the sale did not eventuate. In the meantime, Black Arrow embarked on a second voyage to the Near East, with ports of call including Constantinople, Smyrna, Varna, Bulgaria, and Constanța. Departing New York on the 21st, the ship returned via Gibraltar and Madeira, Spain, clearing the latter port 21 March
 and arriving at New York 2 April. Her passengers on the return trip included the captain and 39 crew of the ship Natenna, an American wooden-hulled freighter built during the war which had been lost off Casablanca, Morocco, on 8 March. Black Arrow's return cargoes included $119,000 of antique and new Persian rugs—reportedly the first such shipment to the United States since the end of the war—which were later offered at retail prices ranging from $59 to $2,250.
USS Black Arrow