took place with its Chinese crew. The fishermen did not speak English, but Blackfish′s crew exchanged grins with them, and traded bread and canned food to them for a string of squid. While patrolling in her lifeguard area, Blackfish came across several naval mines and attempted to detonate them with .45-caliber (11.43 mm) Thompson submachine gun fire, which proved ineffective. Eventually, she used her 20-millimeter gun to destroy the mines. She also encountered an oil slick accompanied by a smell of diesel fuel, leading Sellars to contemplate the possibility that another submarine was in the area. On 3 April 1945, Blackfish encountered more mines in need of disposal, although she later identified one of the supposed mines as an old oil drum. April 1945 continued with Blackfish engaged in routine patrolling and lifeguard duty and little more than sightings of occasional mines, numerous junks, and a few aircraft. She requested permission to venture to different sectors of her patrol area to try to find targets, but these requests were denied. On 22 April, she received orders to end her patrol the next day. Early on the morning of the 24 April, she surfaced near Pratas Reef and shelled a Japanese radio tower on Pratas Island to use up the remainder of her ammunition, scoring at least twenty hits, and leaving the tower in a brown pall of smoke. She then shaped a course for Saipan. Blackfish arrived in Tanapag Harbor on Saipan on 27 April 1945 and took on of fuel. She got back underway by 10:00 the same day. On 1 May, she set course for Pearl Harbor, which she reached on 10 May, bringing her patrol to an end. The patrol was not deemed worthy of the Submarine Combat Insignia, prompting Sellars to suggest that Blackfish′s repeated assignments to an operating area known to U.S. submariners as "Convoy College" was denying her an opportunity to find targets, and that her next patrol should be in what U.S. submariners called the "Empire Area", closer to the Japanese Home Islands, where targets were more plentiful and Blackfish′s crew would have a chance to earn the insignia. Twelfth war patrol On 14 June 1945, Blackfish put to sea from Pearl Harbor to begin her twelfth war patrol, headed for the Nanpō Islands, East China Sea, and Yellow Sea. Once again, her primary mission was lifeguard duty in support of airstrikes. She