The Tenryu-class cruiser of the Imperial Japanese Navy
The Tenryū-class cruiser (天龍型軽巡洋艦 ) was composed of two light cruisers: Tenryu and Tatsuta. This kind of light cruiser class was the first to be operated by the Imperial Japanese Navy. During the was they were very active participating in major operations in secondary roles. The weaknesses and advantages of their designs were used to build the larger and improved Kuma-class cruisers. The Tenryu cruiser design was intended to play the role of flagship for destroyers so that the capabilities of these vessels were similar to those of the destroyers themselves. Some features resembled those from the Royal Navy Arethusa class and C-class cruisers. The similarity in their designs come from the fact that the Royal Navy industries and Japanese shipbuilding industry had long periods of cooperation. They were planned during 1915, and ordered formally in the 1916 fiscal year with a cost of 4.55 million yen.
The design had several problems because the latest Japanese destroyers such as the Minezake class had a faster speed of up to 39 knots! So that the Tenryu could not follow and play the designed role of flagship. The planned series of 6 ships were finally reduced to only two. Between 1935-1936, it was planned to covert them into anti-aircraft or anti-submarine platforms but busy schedules of Japanese shipyards constructing major ships forced to abandon the plans. In addition, new destroyers class, such as the Akizuki-class destroyers, assumed the anti-submarine and anti-aircraft roles in a more versatile manner.
After improvements in oil-fired turbine engine technology and the use of Brown Curtiss geared turbine engines, the Tenryū class got more than twice the horsepower of the previous Chikuma class, and were capable of 33 knots (61 km/h).
The weakness came from the weapons they carried. The Tenryu-class was weaker than any other contemporary cruiser because the main battery for the Tenryu class consisted of four 14 cm/50 3rd Year Type naval guns. These kind of batteries were also used as the secondary battery on the Ise-class battleships. In addition, they had limited angle of fire. Another drawback was that they lack of room for anti-aircraft guns.
However, the Ternryu- class also was the first to use triple torpedo launchers, with two centerline-mounted Type 6 21-inch launchers. No reloads were carried. The hull design was somehow longer than that of destroyers but not too much. The armor protection for the hull was weak, designed primarily against the 102 mm weapons used on contemporary United States Navy destroyers.
Both units, the Tenryu and the Tatsuta, were refitted and modified in 1930 and 1933, respectively. Several others followed in the late 30s and early 40s. Of the two vessels that were built in the Tenryū class, neither of which survived the Pacific War. The Tenryu was sunk after the Naval Battle of Guadalcanal by USS Albacore, and struck on 20 January 1943. The Tatsuta was sunk while bound for Saipan by USS Sand Lance, 40 nautical miles (74 km) NNE of Hachijōjima on 13 March 1944. on May 1933, the Tatsuta was struck.