Kasatka-class submarine

The Kasatka class were a group of submarines built for the Imperial Russian Navy. The six boats were built between 1904 and 1905. They were designed by I.G. Bubnov and were based on the Delfin. The first boat Kasatka experienced significant problems with stability on trials and had to have extra flotation added. The boats were re-built around 1910 with diesel engines added (120 hp) and new conning towers replacing the older structure.

Ships
All six boats were built by Baltic works St. Petersburg and launched in 1904