360 miles SE of Okinawa. Around 1700, when the surfaced I-58 is running northwards at 12 knots, her Type 3 detector detects multiple radar impulses. Soon thereafter masts are sighted on the horizon. LtCdr Hashimoto orders to dive.
At 1716, a 15,000-ton seaplane carrier escorted by one destroyer is sighted. Kaiten No. 3 piloted by FPO1C Hayashi Yoshiaki is launched at 1758 from an estimated distance of 8,800 yards. In reality, the "seaplane carrier" is Landing Ship Dock USS OAK HILL (LSD-7), escorted by THOMAS F. NICKEL (DE-587) enroute from Okinawa to Leyte.
At 1826, the lookouts on OAK HILL report a periscope 1000 yards away on the port quarter. LtCdr Claude S. Farmer's THOMAS F. NICKEL turns toward the attacker, making flank speed. At 1830 the lookouts on NICKEL sight a wake of an apparently broaching torpedo. The DE heads towards the direction opposite to that of the torpedo and fires a shallow pattern of depth charges from her K-guns, mistakenly indetifying the attacker as a conventional submarine. NICKEL's sonar fails to make a contact.
At 1837, OAK HILL reports an incoming torpedo wake directly astern. The lookouts on the DE observe a "submarine" breaking the surface in the wake of OAK HILL. When THOMAS F. NICKEL attempts to ram it, a scraping noise is heard in her forward and after fire rooms and the after engine room along the port side of the bilge. At 1842, OAK HILL reports that the "object" is still chasing her about 2,000 yards astern, although now moving somewhat slower. Suddenly, the kaiten stops, breaks surface and self-detonates, sending smoke and water about 200 ft into the air at 21-15N, 131-02E.
At 1905, lookouts on THOMAS F. NICKEL sight another periscope dead astern of OAK HILL. The DE charges, firing a shallow depth charge pattern. A secondary explosion follows 50 ft outside of the pattern, throwing a black 50-feet geyser of oil and water in the air. A long oil slick is also sighted.
