USS Sea Dog (SS-401) - Fourth War Patrol

Fourth War Patrol

Refit took Sea Dog into May, when preparations were made for her last foray into Japanese home waters. Additional duties during the patrol included those of flagship for the nine-submarine Japan Sea Patrol Pack (TC 17.21). On 27 May, she departed Guam with the other two submarines of her immediate pack, Spadefish (SS-411) and Crevalle (SS-291). Later that day, the ships separated to proceed independently, planning to rendezvous on 4 June. On 28 May, one of Sea Dog’s crew became seriously ill and was diagnosed as a possible pneumonia case. On 29 May, the submarine rendezvoused with Lamson (DD-367) and, after transferring the patient to that destroyer, continued on to the Sea of Japan.

On arrival, Sea Dog reconnoitered the approaches to western Honshū ports to locate minefields; then took up station off the east coast of Sado Shima. At 2000 on 9 June, she sank her first target of the patrol, the small cargo ship, Sagawa Maru. Twenty-three minutes later, she made her second contact; and, at 2044, she fired three torpedoes at another merchant ship, the Shoyo Maru. One torpedo hit, starting a fire aft. Sea Dog pulled away, watched, then moved in for the coup de grace. Two more torpedoes were fired, one ran erratic; the second hit amidships. The target exploded; her bow broke off; and her stern assumed a 60-degree down angle.

Soon afterward, Sea Dog cleared the Niigata area and headed north to patrol off Sakata and Akita. On 10 June, she closed Oga Hanto, and that night she patrolled northwest of Kiskakata and northeast of Tobi Shima. On 11 June, she returned to the vicinity of Oga Hanto. Shortly after 1300, she made contact with another coastal freighter, surfaced, and commenced running west and north to intercept. At 1519, she dived. At 1555, she fired one torpedo. Forty-three seconds later, the torpedo hit; and the target, cargo ship Kofuku Maru, broke in two, up-ending both the bow and the stern.

Sea Dog resumed her patrol to the southward. That night, she took up station to the north of Nyudo Saki and, at 0635 on 12 June, sighted a small convoy as it rounded that headland and continued northward, through relatively shallow waters, toward Henashi Zaki. Sea Dog fired on the freighter farthest from the coast. Shinson Maru broke in two and sank in about two minutes. Her companions moved even closer to the coast. Sea Dog headed for deeper water and patrolled to the southwest.

On 13 June, Sea Dog was still off Oga Hanto. That evening, the starboard mine clearing cable, installed during the previous refit at Guam, parted and fouled the starboard screw. Sea Dog cleared the Japanese coast and stopped, lying-to while attempts were made to get divers down. Leaks in the face mask of the shallow water diving outfit, however, proved impossible to repair; and, soon after 0130 on 14 June, the submarine got underway. The noise and vibration from the starboard shaft was found to occur only for short periods at low speeds. At high speeds, its performance was satisfactory, and Sea Dog resumed her patrol, setting a southwest course for a surface patrol across the approaches to Akita, Sakata, and Niigata.

With daylight on 14 June, she dived, stopped her starboard propeller, and commenced hunting underwater. Less than an hour later, she sighted smoke and attempted to intercept. Her quarry, two cargo ships beat her into Sakata. That night, she moved northward again, and, at 0510 on 15 June, she sighted a passenger/cargo ship standing south past the northern end of Oga Hanto. At 0522, she fired a torpedo which hit just forward of amidships. Koan Maru sank in four minutes. Sea Dog cleared the area as small craft from the beach moved out to pick up survivors.

On 17 June, Sea Dog rotated areas with Spadefish and Crevalle and headed north to hunt along the Hokkaidō coast between Benkai and Kamoi Misaki. Two days later, she sighted three merchantmen moving northward along the coast and attacked, firing two torpedoes at the lead ship and three at the second. The third ship changed course. Sea Dog turned back to the previous targets. The first ship, cargo ship Kokai Maru, was going under, stern first. But, before she could fire again on the second ship, an enemy plane was sighted. Sea Dog dived. At 116 feet (35 m), she grounded; backed off, cleared and then headed north. The plane did not attack.

SS-401 remained in the area for several more days, then headed for Pearl Harbor. On 30 June, she arrived at Midway; and, on 5 July, she entered Pearl Harbor.