Kuma Class Cruiser - Design

Design

The Kuma-class hull design was based on a 5,500 ton nominal displacement, with a high freeboard and light bridge structure, behind which was a tripod mast with the fire control platform and two searchlights. The design proved so versatile that it became the standard upon which all future light cruisers in the Japanese navy would be based.

The propulsion system for the Kuma-class was based on four axial deceleration turbines with 12 boilers, providing 90,000 hp (67,000 kW). Ten boilers were designed to burn heavy oil, and the remaining two burned a mixture of coal and oil. With improvements in geared-turbine engine technology, the Kuma-class vessels were capable of the high speed of 36 knots (67 km/h), and a range of 9,000 nmi (17,000 km) at 10 kn (12 mph; 19 km/h) . The silhouette of the Kuma-class was discernible by its three smoke stacks, with the stacks flaring out in a trumpet shape.

The number of 14 cm/50 3rd Year Type naval guns was increased from three on the Tenryū-class to seven on the Kuma-class, centerline mounted in individual gun turrets, (two fore, three after and one on either side of the bridge). The positioning meant that only six of the guns could be brought to bear in a broadside. As with the Tenryū-class, the Kuma-class remained highly deficient in anti-aircraft protection, with only two 8 cm/40 3rd Year Type naval guns and two 6.5 mm machine guns. Provision was made for 48 naval mines. The two triple torpedo launchers on the Tenryū-class was changed to four double launchers, placed in pairs so that four torpedoes could be fired on each side. Eight reloads were also provided.

Kiso was unique in that it had both a forward and aft flat surfaced superstructure, with a rotating floatplane take-off platform located aft. The platform appears to have never been used, and was removed in 1922, but her superstructure retained the shape of the hanger.