Klass Horn was built by Prussia for King Nikolai I of Montenegro in 1892. After its bankruptcy, it was purchased by Russia and became the flagship of the czar's fleet. After the Russian revolution in 1918, it was taken over by the Finnish navy and renamed Klas Horn. At the beginning of acquiring the ship, the Finnish navy wanted to convert it into a mine laying ship, but after the transformation in the 1920s, it was used as a gunboat. In the 1930s, the aging Klass Horn ended its service and turned to be a mother ship for marine survey. But according to other information, she may actually have joined the earliest submarine formation in Finland as a submarine mother ship. The submarine is 57.2m long, 7m wide, 3.1m draft, 420t displacement, 19 knots speed, steam power. In terms of weapons, the Finns initially equipped the ship with two 102mm French cannon after taking over. For this ship, it can be said that a small boat carries a large cannon, so that the cannon must be fixed with ropes to avoid affecting the stability of the ship. Even so, its seaworthiness is still poor, so it may be replaced with a 75mm cannon later, with 50 mines. The ship did not participate in the battle, and it existed as a floating hotel and restaurant 57 years later, until it was finally abandoned.