S-9 Class Minesweepers:
Successor class of the Sokaitei-1 units, the S-9 class were based on the Japanese W-13 Minesweepers. Differing from their IJN siblings by having a straight quarterdeck they were 74m long, 8,2m abeam and drafted 2,1m for a displacement of 525T. Armed with 2 120mm guns and two single 13mm machine guns for AA duties they were capable of 20 knots with a 2.600 nautcial miles endurance at 12-knots.
Koko no Kaigun ordered eight units for the class, the first two units S-9 and S-10, were laid down in December 1931 and ultimately commissioned in late 1933.
By the time the Tomozoru incident happened S-11 through S-14 had already been laid down. to correct the ensuing stability issues S-9 and s-10 were refitted to reduce topweigh, the other units recieved modifications before beign commissioned.
The last two units, S-15 and S-16 were delayed unitl early 1935 and were of an improved design. Draft was increased to 2,5m bringing the displacement to 616T, fuel bunkerage was increased to maintain the 2.600-nm range, but top speed decreased to 19 knots. Topweight was further reduced resulting in a slightly different bridge structure. They also featured a sighly different midship break. Such modified the last units of the class entered service in 1936.
As it was for the S-1 class, the war exacted it's toll. S-9 was sunk in 1942, with S-11 and S-13 following in 1943 and 1944 respectively. The 5 surviving units were recalled for minesweeping dutied around kokan home waters in response of the US advance. The ships were refitted by recieving an hydrophone and increased depth charge inventory. A type-13 air-search radar was also installed. The two 13mm machine guns were removed and replaced with two twin and four single 25mm machine guns. S-10 and S-12 were sunk in late 1945. Just before the start of Koko uprisings the remaining three units recieved a camouflage paintjob.
In early 1946 S-14 and S-16 were both sunk during an US bombardment on Mitsuminato Harbor. S-15 was bombed a few days later in Nadayoko's harbor, severly damaged she was beached to prevent her sinking. After the war she was declared a constructive total loss and was promptly decommissioned and scrapped.
Ships in class: (laid down-launched-commissioned - fate)
S-9 1931-1933-1933 - Sunk 1942
S-10 1931-1933-1933 - Sunk 1945
S-11 1932-1933-1934 - Sunk 1943
S-12 1933-1934-1934 - Sunk 1945
S-13 1933-1934-1934 - Sunk 1944
S-14 1934-1935-1935 - Sunk 1946
S-15 1935-1935-1936 - Decommissioned 1946
S-16 1935-1935-1936 - Sunk 1946