Whether that ship was "Seal"s target or the colliding ship is not known, but it is possible that the freighter's hull had been badly punctured by the submarine's periscope shears. On 17 November, "Seal" was ordered to start for Pearl Harbor. She arrived on 30 November, and after temporary repairs, continued on to the Mare Island Navy Yard for permanent repairs. On 2 April 1943, she returned to Hawaii, and 12 days later, she departed on her sixth war patrol. On 18 April, she topped off at Midway Island, and by 1 May, she was patrolling off the Palau Islands. On 2 May, she attacked a freighter, but missed and subsequently came under an aerial bombing attack. On 4 May, she sank "San Clemente Maru", but for the remainder of the patrol, was unable to close any targets. "Seal" returned to Midway on 3 June. Refit took two weeks; further training took a third. On 24 June, she was ready for sea. On 2 July, she entered her area off Todo Saki on the northeastern Honshū coast, and on 8 July, she underwent a severe, ten-hour, depth charging which resulted in persistent air and oil leaks and forced her to turn back for repairs. She arrived at Pearl Harbor on 24 July. Her repairs were quickly completed, and in mid-August, she sailed west again. On 27 July, she entered the southern Kuril Islands. On 31 July, while the submarine was diving, the conning tower hatch failed to latch, and subsequently flew open. The pumproom was flooded before the boat could be surfaced. Substantial damage to her electrical circuits resulted and "Seal" retired eastward to make temporary repairs. The work continued for a week, and on 8 August, as the air compressors were being jury-rigged to provide sufficient air pressure to launch torpedoes, she returned to the Kurils and crossed into the Sea of Okhotsk. On 17 August, she attacked two freighters with no success. On 25 August, she cleared the area, and on 4 October, she returned to Pearl Harbor. During her next war patrols, "Seal" provided lifeguard services and conducted reconnaissance missions—at Kwajalein on her ninth - from 7 November-19 December - and at Ponape on her tenth - from 17 January-6 March 1944. "Seal" proceeded to Mare Island, and after re-engining and overhaul, returned to the northern Hokkaidō–Kuril Islands area for her eleventh war patrol, from 8 August-17 September.