On 4 May, "Wahoo" proceeded to reconnoiter the northeast tip of Etorofu Island; she found nothing and changed course to the southeast. Morton positioned the boat to intercept the seaplane tender . The submarine submerged and fired a spread of three torpedoes. The first hit between the stack and bridge; the other two missed. "Kamikawa" turned away and was making , with a slight list. ("Kamikawa" survived but was sunk 29 May 1943 by the .) "Wahoo" continued on an easterly course, surfaced and continued her patrol of the Kurils southward.