F-16 Class Minelayer:
Just after the design for the F-13 class minelayer was approved Koko no Kaigun designers went back to the drawing board to design a nother class of Minelayers. Planned to further replace the ships of the Fusetsukan 1 class, the new ships were based on their predecessors. Overall lenght remained roughly the same, at 107,5m but waterline lenght was increased by 1,5m, Beam increased from 11,5 to 11,8m, as draft slightly did from 3,1 to 3,2m. Thus redesigned, the hull's overall displacement went up to 1.970T and increased usable internal space. The ships carried a complement of 300 mines, all stowed internally and arranged in six rails, to be laid through as many hatches located at the stern. Armament was completed by three single 140mm gun mounts and two 40mm machine guns for anti-aircraft duties. Oil firing boilers generated enough power to push the ships to 19knots, what was needed to operate toghether with the Fusetsukan 13 units. Overall, the planned minelayers bore a slight resemblance to the Japanese ship Itsukushima, but that just ended at overall appearance and main armament, as everything else was decidedly different.
The two ships planned for the class, now named Fusetsukan 16 and Fusetsukan 17, were laid down in 1929 and 1930 respectively. Both were launched in 1931 and commissioned in 1932.
During the second half of the 1930's, after IJN Tomozoru's capsizing, concern arose on the ship's stabilty. As the two units of the F-16 class were known to have a less than satisfactory roll performance because of their hight funnel and bridge, it was decided to refit them as to solve those issues. During 1937 both ships had their funnel cut down and the bridge structure reduced in height by a deck. To make up for the internal space lost, an enclosed deckhouse was added below the boat deck. during the same timeframe the RDF equipment was added and the single 40mm machine guns were replaced by two twin 25mm ones.
After the start of the Pacific War, together with the F-13 class, both units were sent in Aleutian waters at first, then south to the Solomon Islands. F-17 was sunk there in early 1943, caught by USN carrier-based planes off Santa Cruz Island. F-16 survived long enough to escape both the Carrier raids on Rabaul and Truk in November 1944 and February 1945. She returned home where she was fitted with Type 13 and 22 radars, two triple 25mm machine guns were alsoa dded. F-16 was then deployed for the Aleutians once again. Here, on October 18th, she was torpedoed and damaged by an US submarine. The ship returned to Koko and was drydocked at Kumoi Arnsenal for repairs. During her repairs one of the 140mm guns was landed and four triple and a single 25mm machine guns added, for a total of 23 barrels. An hydrophone was installed and eight depth charge throwers and two rails were fitted and she recieved a camouflage scheme.
When Koko uprisings started mere days later F-16 was dispatched to Mitsuminato, were she remained until early January 1946, then on the 27th, US bombers attacked the harbor. F-16 crew managed to put up the engines and attempted to flee for the open sea. Just minuts later a bomb hit the fantail detonating the depth charges, F-16 lost both screws and steering and was then hit multiple times before rolling over and sinking. Her wreck was raised and scrapped after the war.
Ships in class: (laid down-launched-commissioned - fate)
F-16 1929-1931-1932 - Sunk 1946
F-17 1930-1931-1932 - Sunk 1943