The following afternoon, the auxiliary cruiser gave up her vigil for "Purissima Concepcion" off Cienfuegos and set a course back to the eastern end of Cuba. She rejoined the Santiago blockade on 16 June but put into the anchorage at Guantanamo Bay the following day to take on coal. Late on the 18 June, the ship returned to sea bound once more for blockade duty off Cienfuegos. On the 19 June, during the passage from Guantanamo Bay to Cienfuegos, "Yankee" stopped and inspected two sailing vessels—a British schooner and a Norwegian bark—and a steamer, the British SS "Adula". All three had their papers in order, and the auxiliary cruiser allowed them to proceed unmolested. That evening, she arrived off Cienfuegos and began cruising on blockade station between that port and Casilda. At about 08:30 on the morning of 20 June, "Yankee" sighted a steamer lying in Casilda harbor closely fitting the description of "Purissima Concepcion". The American ship stood in as close to the shoals as she dared and then fired a shot across the steamer's bow in an unsuccessful effort to make her show her colors. Instead, the merchantman began preparations for getting underway. Yankee responded by opening a steady fire at extreme range. As the supposed Spanish steamer moved farther into shoal water and disappeared behind some islets, "Yankee" shifted fire to an enemy gunboat and a floating battery, both of which had opened an ineffective fire upon her. The extreme range—in excess of —made the gunfire from both sides so ineffective that "Yankee" broke off the engagement and resumed her patrols between Casilda and Cienfuegos. The auxiliary cruiser continued her blockade of that stretch of the Cuban coast until 24 June, when her dwindling supply of coal forced her to head for Key West. "En route" to that base, she visited the Isle of Pines where she captured and destroyed five Spanish fishing vessels on the 25 June. "Yankee" arrived in Key West on 27 June and began taking on coal. She completed her refueling operation and departed Key West on 3 July, bound for New York, where she arrived two days later. She remained at New York until the 12 July, taking on ammunition for transportation to the Eastern Squadron on the Cuban blockade. On 13 July, she reached Norfolk, where she spent another four days taking on additional ammunition for the ships of the blockading squadron.