The Japanese Destroyer Kagero

The propulsion system consisting of a pair of steam turbines developing 52 000 shp and three Kampon boilers could accelerate the ship to 35 knots. The system was surprisingly fuel efficient, which translated into a projected operating range of 5 000 nm at 18 knots. During sea trials the actual range was demonstrated to be over 6 000 nm – a clear advantage for a warship operating in the vast expanse of the Pacific.
Kagero’s offensive armament can only be characterized as heavy. The main battery consisted of six 127 mm guns mounted in three lightly armored and fully enclosed turrets. The main guns had an effective range of some 19 km and were widely used on most Japanese destroyers of the time. They were considered solid weapons, although their effectiveness against airborne targets left much to be desired due to rather unimpressive angle of elevation (55°) and the rate of fire not exceeding 5 to 10 rounds per minute. The turrets’ rate of rotation was also insufficient to target fast flying U.S. Navy aircraft.
The Kageros’ real forte was their torpedoes. The ships mounted two quad Type 92 Model 4 launchers, complete with light enclosures to allow for ease of operation in bad weather conditions. Each launcher featured a simple Type 14 torpedo director, although they were only used as back-up for the main Type 91 directors and Type 92 fire control stations. En empty launcher weighed in at 18 tons and measured 8.85 m x 4.6 m x 1.3 m (length, width, height). Both launchers were mounted on the ship’s centerline. The forward launcher stood on a raised platform between the smoke stacks, while the aft one was installed directly on the deck between the aft stack and the aft deckhouse. The tubes could launch deadly effective Type 93 “Long Lance” torpedoes. Those marvels of Japanese weapon technology were reliable, fast, had a long range and packed a huge punch. Their unique feature was the use of highly compressed oxygen as fuel oxidizer, which not only greatly improved the torpedoes’ performance, but also reduced the tell-tail bubble trail typical for conventionally powered weapons. The Type 93 torpedo was superior to its U.S. counterpart – the Mark 15 (see Table 2). The U.S. Navy had a taste of its deadly efficiency on many occasions, including the Salomon Islands campaign. The launchers mounted on the Kagero class destroyers could be reloaded within 20–30 minutes1 and each ship carried 16 Type 93 torpedoes.
The defensive armament consisted of four 25 mm AA guns and 13 mm machine guns2. During wartime refits the ships received additional 25 mm guns (twenty in total), but the AA capability continued to be the Kageros’ weak spot. In actual combat the greatest threat to the destroyer proved to be enemy aircraft and neither 127 mm main guns, nor the 25 mm AA cannons could provide adequate protection against them. The 25 mm cannons did not have the range or the rate of fire to be truly effective anti-aircraft weapons. In addition, the 25 mm rounds were simply not powerful enough when used against aircraft. What the Imperial Navy needed was a weapon similar to 40 mm Bofors mounted on the U.S. Navy vessels. In the absence of those the best they could do was to increase the number of AA guns mounted on their warships, but that did little to truly resolve the issue of insufficient protection against airborne threats. The Kagero class destroyers were also rather limited in their ASW capabilities. The ships carried only two depth charge throwers with a supply of only 16 charges. Although that number was increased to 36 in 1943, it was still far from enough.
The electronics suite was another weak area of the Kageros. Although one of the Kagero class destroyers, the Hamakaze, did receive the Type 22 radar in 1942, the unit was far inferior to its U.S. counterparts. In fact, during the entire war the Imperial Navy stayed well behind the Americans in the development of radar technology and never managed to close that gap. One of the stop-gap measures adopted by the Japanese was the installation of E-27 radar warning receivers on their warships, although this barely scratched the surface of the real issue. During wartime refits Type 21 and Type 22 radar sets were installed on Japanese warships, but those too were not nearly as good as the similar units carried by the U.S. Navy vessels. The Japanese did have excellent binoculars that could also be used at night, but even the best of those could not compete with a potent radar set.
In summary, the Kagero class destroyers were quintessential fast warships with a huge offensive armament potential. However, by placing too much emphasis on the ships’ surface warfare capabilities, the designers failed to address the issues of anti-aircraft and anti-submarine protection. Deficiencies in Japanese radar technology did not help the matters either. The Japanese did try to overcome those problems, but in terms of anti-aircraft and anti-submarine warfare their warships were outperformed by the USN vessels throughout the war. Despite those issues the Kagero class was a good design. Whatever their limitations, they were not caused by design flaws or inherent shortcomings of the vessels themselves, but rather by faulty and unrealistic naval doctrine adopted by the high command of the Imperial Japanese Navy. Development of effective medium caliber HA guns or ASW systems was well within the capabilities of Japanese naval engineers of the time. However, the Japanese naval commanders, possessed by the overwhelming offensive spirit, did not believe the defensive systems deserved more than a passing glance. This attitude caught up with them during the war in the Pacific and Kagero class destroyers were among its victims.

Kagero’s operational history