"Sea Dog" remained off the Kyūshū coast for another day; then moved north to lifeguard duty south of Sagami Wan. Although assigned to cover both sides of the Izu Shoto, resulting in much of her time being spent on high speed runs south around Mikura-jima with no rescues being made at the end of the runs, potential target opportunities increased. On 2 April, she sighted and fired on a small minelayer. All torpedoes missed. On 16 April, she sank a medium-sized cargo ship, "Toko Maru", between Hachijo Jima and Mikura-jima. A typhoon then interrupted both hunting and rescue operations; and, on 23 April, she headed for Guam.