Shiratsuyu-class destroyer

The Shiratsuyu-class destroyers (白露型駆逐艦) were a class of ten destroyers of the Imperial Japanese Navy in service before and during World War II.

Background
The initial six Shiratsuyu class destroyers were modified versions of the Hatsuharu-class destroyer, and had been originally planned as the final six vessels of that class under the ”Circle-One” Naval Expansion Plan.

However, design issues with the Hatsuharu class ships, notably their “top-heavy” design relative to their small displacement, resulted in extensive modifications, to the point where the final six vessels on order were named as a separate class. An additional four vessels were ordered under the ”Circle-Two Naval Expansion Plan of fiscal 1934, and all vessels were completed by 1937.

As with the Hatsuharu-class, the Shiratsuyu-class destroyers were designed to accompany the Japanese main striking force and to conduct both day and night torpedo attacks against the United States Navy as it advanced across the Pacific Ocean, according to Japanese naval strategic projections. Despite being one of the most powerful classes of destroyers in the world at the time of their completion, none survived the Pacific War.

Design
In general layout, the Shiratsuyu-class vessels closely resembled the Ariake-sub-class, or final version of the Hatsuharu-class, differing only in the more compact bridge design and the shape and inclination of the funnels. The hull retained the general configuration of the Hatsuharu class with a long forecastle with a pronounced flare to improve sea-keeping at high speeds by adding buoyancy and reducing the spray and water coming over the deck.

The Shiratsuyu-class were the first Japanese warships to be completed with quadruple torpedo mounts and telephone communications to the torpedo station. As with the Hatsuharu-class. the torpedo launchers were given a protective shield to allow for use in heavy weather and to protect against splinter damage.

Propulsion
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 and a pitch of 3.7 m. The total horsepower of the Shiratsuyu-class was only 42000 hp compared to the 42000 hp of their Fubuki-class predecessors, but the machinery was significantly lighter and more powerful on a unit basis. The Shiratsuyu's machinery weighed only 106 t compared to the 144 t of the Fubuki-class, or 396 shaft horsepower per tonne versus 347 shaft horsepower per tonne for the older ships.

Similarly the three Kampon Type Ro-Gō boilers used in the Shiratsuyu-class ships weighed 50 t in comparison to the 51 t boilers used in the Fubuki-class, but produced 14000 hp each while the older boilers produced 12500 hp. 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, just like the older models, but used superheating to improve efficiency while the older boilers simply used saturated steam.

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 4000 nmi at a speed of 18 kn with 460 t of fuel.

Armament
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 was removed on all surviving ships and replaced with from 13 to 21 (depending on the individual vessel) 25 mm Type 96 anti-aircraft guns 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 more single mounts were fitted to ships in the last year of the war.

For example. JAPANESE DESTROYER Hatsushimo mounted ten single 25 guns when she was sunk in July 1945. Four license-built Hotchkiss 13.2 mm Type 93 machine guns were also fitted to Hatsushimo, but these were also of limited utility against modern aircraft.

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 cruiser 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 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. Each tube could be reloaded in twenty-three seconds using the endless wire and winch provided.

Only eighteen depth charges were initially carried in a rack at the stern, but this increased to thirty-six after the autumn of 1942. 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.

Radar
Radar was not installed on the surviving ships of this class until late in the war, possibly as late as 1944. They 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.

Operational history
None of the Shiratsuyu-class ships survived the Pacific War. The lead ship of the class, JAPANESE DESTROYER Shiratsuyu was sunk northeast of Mindanao in a collision with the oiler Seiyo Maru. Most of the class were lost by US submarines, and Kawakaze, Yudachi, and Murasame being lost in surface actions. Only Harusame fell victim to aircraft.

JAPANESE DESTROYER Murasame was employed in several campaigns, beginning with the invasion of the Philippines. In 1942 she participated in the Battle of the Java Sea and the Battle of Midway. During the Guadalcanal Campaign Murasame played a supporting role in the Battle of the Eastern Solomons and the Battle of the Santa Cruz Islands and was sunk at the Battle of Kolombangara.

JAPANESE DESTROYER Shigure was squadron flagship of Captain Tameichi Hara through much of 1942-43, and became one of the most famous Japanese destroyers of the war. She survived numerous battles in the Solomons (including being the sole survivor of the Battle off of Kolombangara), until she was torpedoed and sunk off the Gulf of Siam by USS Blackfin (SS-322) in early 1945.

Books

 * OCLC 77257764
 * OCLC 77257764
 * OCLC 77257764
 * OCLC 77257764
 * OCLC 77257764
 * OCLC 77257764