The No. 1-class submarine chaser (第一号型駆潜艇, Dai 1 Gō-gata Kusentei) was a class of submarine chasers of the Imperial Japanese Navy (IJN), serving during World War II. Three vessels were built in 1933-36 under the Maru 1 Programme and the Maru 2 Programme. They have two sub classes.
Background
In World War I, German U-boat raged. The IJN began maintenance of an anti-submarine boat as a lesson in this, because Japanese shoreline and sea-lanes were very long. The IJN had some submarine chaser type tugboats and yard ferries. However, they were small and their speed was low.
The IJN wanted to give the anti-submarine boats a speed of more than 20 knots, because their Kaidai III submarine already achieved a 20kt surfaced.
The No. 1 and the No. 2 were completed in March 1934, and they were assigned to the 1st Submarine Chaser Division, Yokosuka Naval Defence Squadron.
However, because of their very shallow draft they lacked the rolling performance. This fact become evident after the Tomozuru incident.
The Tomozuru incident affected the No. 1-class. The No. 1 and the No. 2 were sent to the Uraga Dock Company in July 1934, and repairs were started. They were equipped 80 tons ballast and mounted a ballast keel. The drawings for the No. 3-class boat was also revised.
Service
Late 1934, Repairs were completed.
October 1936, The No. 3 assigned to 1st SchDiv. They always shared an action afterward.
In 1938, the 1st SchDiv was transferred to the No. 1 Base Force (Shanghai).
On 5 September 1941, the No. 1 Base Force was transferred to the 2nd Fleet.
On 1 May 1942: The 1st SchDiv was dissolved. They spent all their time for escort operations in the Java Area.
Ships in classes
No.1-class
Project number was K3. 2 vessels were built under the Maru 1 Programme. They equipped the MV hydrophone by Submarine signal company and latest active sonar the Type 93.
Project number was K4. Only 1 vessel was built under the Maru 2 Programme. The No. 3 was equipped the French SCAM active sonar and latest hydrophone the Type 93. The No. 3 was classed in the No. 1-class in the IJN official documents.
Ship
Builder
Laid down
Launched
Completed
Fate
No. 3
Asano Shipyard
17 April 1935
6 June 1936
5 October 1936
Scuttled by Royal Navy off Singapore on 11 July 1946. Decommissioned on 10 August 1946.
Photos
No. 2 in 1934
No. 3 in 1936
Footnotes
^Submarine chaser No. 1 (第1号駆潜艇, Dai 1 Gō Kusentei). The same shall apply hereinafter.
Bibliography
Ships of the World special issue Vol. 45, Escort Vessels of the Imperial Japanese Navy, "Kaijinsha"., (Japan), 1996.
The Maru Special, Japanese Naval Vessels No. 49, Japanese submarine chasers and patrol boats, "Ushio Shobō". (Japan), 1981.
Imperial Japanese Navy
No. 2 in 1934
No. 3 in 1936
