Shiratsuyu-class destroyer

The Shiratsuyu class, as with the previous Hatsuharu class, carried two sets of Kampon geared turbines, one for each shaft. Each set consisted one low-pressure and one high-pressure turbine, plus a cruise turbine connected to the high-pressure turbine. The LP and HP turbines were connected to the propeller shaft by a two-pinion reduction gear. Each propeller had a diameter of 3.05 m (10.0 ft) and a pitch of 3.7 m (12 ft). The total horsepower of the Shiratsuyu class was only 42,000 hp (31,000 kW) compared to the 50,000 hp (37,000 kW) of their Fubuki-class predecessors, but the machinery was significantly lighter and more powerful on a unit basis. The Shiratsuyus' machinery weighed only 106 tonnes (104 long tons; 117 short tons) compared to the 144 tonnes (142 long tons; 159 short tons) of the Fubuki class, or 396 shaft horsepower per tonne versus 347 shaft horsepower per tonne for the older ships.[5]

Similarly the three Kampon Type Ro-Gō boilers used in the Shiratsuyu-class ships weighed 50 tonnes (49 long tons; 55 short tons) in comparison to the 51 tonnes (50 long tons; 56 short tons) boilers used in the Fubuki class, but produced 14,000 hp (10,000 kW) each while the older boilers produced 12,500 hp (9,300 kW). This gave a ratio of 3.6 kg per shaft horsepower for the Shiratsuyu class compared to the 4.1 kg per shaft horsepower of their predecessors. The newer design of boilers initially used steam pressurized to 20-bar (290 psi), just like the older models, but used superheating to improve efficiency while the older boilers simply used saturated steam.[6]

A single 100 kW turbo-generator was fitted behind the reduction gears in a separate compartment and two 40 kW diesel generators were located between the propeller shafts. As initially completed the Shiratsuyu class had a range of 4,000 nautical miles (7,400 km) at a speed of 18 knots (33 km/h) with 460 tonnes (450 long tons; 510 short tons) of fuel.[7]

The Shiratsuyu-class destroyers used the same 50 caliber 12.7 cm/50 Type 3 naval gun as the Fubuki class, but all turrets could elevate to 75° to give the main guns a minimal ability to engage aircraft. During the war the single turret in "X" position was removed on all surviving ships and replaced with two triple Type 96 anti-aircraft guns, while other guns were added so that between 13 and 21 (depending on the individual vessel) of this calibre were eventually carried in double and triple mounts. Although these powered mounts were unsatisfactory because their traverse and elevation speeds were too slow to engage high-speed aircraft[8] more single mounts were fitted to ships in the last year of the war. Four 13 mm guns were also added.

For example, Hatsushimo of the related Hatsuharu class mounted ten single 25 guns when she was lost in July 1945. Four license-built Type 93 machine guns were also fitted to Hatsushimo, but these were also of limited utility against modern aircraft.[9]

The 61 cm Type 90 torpedo was mounted in quadruple tube Type 92 launchers, derived from the twin tube Type 89 launcher used in the Takao-class heavy cruisers. Shields were fitted to both the torpedo mounts and lockers to protect them from the weather and from strafing aircraft. Initially the shields were made from Duralumin to save weight, but these quickly corroded and had to be replaced. "NiCrMo" steel, taken from the air chambers of obsolete torpedoes, 3 mm (0.12 in) in thickness, was chosen for the new shields to save weight. It was traversed by an electro-hydraulic system and could traverse 360° in twenty-five seconds. If the backup manual system was used the time required increased to two minutes. Eight reloads were carried, and each tube could be reloaded in twenty-three seconds using the endless wire and winch provided.[10] Because of the weight of the extra guns added, one set of reloads for the torpedo tubes was removed, together with the minelaying and minesweeping gear. By the start of the Pacific War, all ships of the class were using Type 93 torpedoes.[2]

Only eighteen depth charges were initially carried in a rack at the stern, but this increased to thirty-six after the autumn of 1942, with four depth charge throwers. Apparently no sonar or hydrophones were fitted until after the outbreak of the war when the Type 93 sonar and Type 93 hydrophones were mounted.[11]

Radar was not installed on the surviving ships of this class until late in the war, possibly as late as 1944. Surviving ships were given a Type 22 radar on the foremast, a Type 13 on the mainmast and a Type E-27 radar countermeasures device was carried high on the foremast.[11]

• Evans, David (1979). Kaigun: Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887-1941. US Naval Institute Press. ISBN 0-87021-192-7.
• Brown, David (1990). Warship Losses of World War Two. Naval Institute Press. ISBN 1-55750-914-X.
• Roger Chesneau, ed. (1980). Conway's All the World's Fighting Ships 1922-1946. Grenwitch: Conway Maritime Press. ISBN 0-85177-146-7.
• Howarth, Stephen (1983). The Fighting Ships of the Rising Sun: The Drama of the Imperial Japanese Navy, 1895–1945. Atheneum. ISBN 0-689-11402-8.
• Jentsura, Hansgeorg (1976). Warships of the Imperial Japanese Navy, 1869–1945. US Naval Institute Press. ISBN 0-87021-893-X.
• Lengerer, Hans (2007). The Japanese Destroyers of the Hatsuharu Class. Warship 2007. London: Conway. pp. 91–110. ISBN 978-1-84486-041-8.OCLC 77257764
• Stille, Mark E. (2013). Imperial Japanese Navy Destroyers 1919-45 (1) - Minekaze to Shiratsuyu Classes. Osprey Publishing (No. 198). ISBN 978-1-84908-984-5.
• Watts, Anthony J. (1971). The Imperial Japanese Navy. Macdonald & Co. ISBN 978-0385012683.
• Watts, Anthony J. (1966). Japanese Warships of World War 2. Ian Allan Ltd.
• Whitley, Michael J. (1988). Destroyers of World War 2. Cassell Publishing. ISBN 1-85409-521-8.