PT boatA PT boat (short for patrol torpedo boat) was a motor torpedo boat used by the United States Navy in World War II. It was small, fast, and inexpensive to build, valued for its maneuverability and speed but hampered at the beginning of the war by ineffective torpedoes, limited armament, and comparatively fragile construction that limited some of the variants to coastal waters. In the US Navy they were organized in Motor Torpedo Boat Squadrons (MTBRONs).
MinelayerA minelayer is any warship, submarine or military aircraft deploying explosive mines. Since World War I the term "minelayer" refers specifically to a naval ship used for deploying naval mines. "Mine planting" was the term for installing controlled mines at predetermined positions in connection with coastal fortifications or harbor approaches that would be detonated by shore control when a ship was fixed as being within the mine's effective range. Before World War I, mine ships were termed mine planters generally.
Allied submarines in the Pacific WarAllied submarines were used extensively during the Pacific War and were a key contributor to the defeat of the Empire of Japan. During the war, submarines of the United States Navy were responsible for 56% of Japan's merchant marine losses; other Allied navies added to the toll. The war against shipping was the single most decisive factor in the collapse of the Japanese economy. Allied submarines also sank a large number of Imperial Japanese Army (IJA) troop transports, killing many thousands of Japanese soldiers and hampering the deployment of IJA reinforcements during the battles on the Pacific islands.
Ukuru-class escort shipThe Ukuru-class escort ships were a class of twenty kaibōkan escort vessels built for the Imperial Japanese Navy during World War II. The class was also referred to by internal Japanese documents as the "Modified B-class" coastal defense vessel, and they were the fourth class of kaibōkan. The escort ship was developed after the start of the Pacific War, it became apparent that a design more capable of anti-submarine warfare than the previous and kaibōkan was needed.