In March and April 1971, "Otway" participated in SEATO Exercise Subok. On 26 August 1971, "Otway"s fin was struck by a dummy helicopter-dropped torpedo during training exercises in Jervis Bay. There was only superficial damage to the submarine, which was quickly repaired. On 1 September, the fin was damaged again when a periscope mast was hit by a whale: repairs were completed in Sydney that day. In October, the submarine visited Brisbane for Navy Week, but was forced to sail on short notice and with only two-thirds of her personnel to locate and rescue the crew of the ketch "One and All", which had run aground on Middleton Reef.