JR Potts, AUS 173d AB (Updated: 6/29/2016):
For many years following World War 2, the nation of Japan was not allowed a standing army, air force or navy per se - this primarily due to their contributions on the losing side of the Axis powers (to include Nazi Germany and Italy among others). As such, her military power since has been largely relegated to defensive-type instruments and, as such, the government overseeing the modern Japanese Navy requires a defensive presence suitable for protecting the island chain as well as the large maritime fishing interests and cargo fleets in both home and international waters - a stark contrast to the aggressive resource-hungry nature of the Imperial Japanese fleet of the 1930s and 1940s. To date (2012), the Shirane is 32 years old and is expected to be decommissioned sometime in 2014.
The Shirane's design profile is characterized by sharp clean lines even with a bulbous bow sonar. There is a compact superstructure forward of amidships and aft of 2 x 5-inch dual-purpose stepped deck guns. Between the superstructure and deck guns is the ASROC 8-shot anti-submarine torpedo launcher. The fire control system (FCS) is mounted atop of the bridge superstructure and the air-search radar is affixed to a platform extending out near the top of the forward funnel. A small pagoda sits atop the forward funnel housing the surface search radar and applicable weather sensor equipment. Aft of the superstructure is a lower hanger deck for the three helicopters assigned to the ship. The two 20mm CIWS (Close-In Weapon System) Gatling-type guns are located on stands, one to portside and the other to starboard, nearly positioned on the ship's centerline atop the helicopter hanger. The shorter aft funnel protrudes from the hanger deck roof and the Sea Sparrow surface-to-air medium-range missile launcher (a successful navalized version of the air-to-air Sparrow missile) is mounted on top of the hanger deck aft of the funnel. A large flight deck extends rearwards from the two hanger deck doors to the fan tail. An open air secondary deck is located under the flight deck on the fan tail and has stowage space for the towed sonar gear. In all, the Shirane manages four complete decks below the main deck.
As the Shirane was built to defend against all manner of threats including submarines, surface and air threats and she can be further called upon for shore bombardment if needed. Starting from the bow, she fields 2 x 5-inch /54 caliber Mk 42 automatic guns which were designed for air or surface targets (dual-purpose). However, as air targets continued to increase in cruising speeds, the Mk 42 became more of a surface threat counter weapon. The two 5-inch guns are controlled by the Mk 68 Gun Fire Control System (FCS) located at the superstructure and on top of the gun mounts. The entire Mk 42 system weighs 60 tons. Under the gun mount are two drums that hold 40 rounds each of 5-inch shells. each projectile weighing 70 pounds each. However, the guns cannot sustain the manufactured specifications of firing 40 rounds per minute (the actual maximum rpm fired is 33 or about 1 round every 2 seconds per gun, this based on the information provided on the Shirane itself). In each of the two gun mounts, the storage space capacity is 599 rounds of the 5-inch shells. When fired the 5-inch shells travel at a velocity of 2,300 feet per second with a maximum range of 14.9 miles (26,224 yards) at 45 degree elevation.
Aft of the twin 5-inch gun mounts is a MK-112 matchbox-type RUR-5 ASROC ASW system launcher developed in the 1950s. This anti-submarine weapons system is a rocket assisted launcher holding 8 x homing Mark 46 torpedoes (unknown if reloads are carried below deck). Each torpedo weighs 950 with and is 15.1 feet long and has an internal guidance system. The launcher can pivot and fire to port or starboard or forward over the bow of the ship as needed. The superstructure obviously obstructs launching these torpedoes to the stern. Additional ASROC torpedo launchers may be installed. If the onboard ship's sensors or the sonar on the SH-60J accompanying helicopters detect an enemy submarines location, this data is fed into the acoustic homing torpedo for an ASROC attack. The torpedo is then launched into the air by its solid propellant rocket motor until reaching a preprogrammed moment in flight to which the torpedo separates from its rocket booster, lowered into the water by a parachute. The torpedo then actively homes in on its target in the usual sense using active or passive sonar. This quick-reaction delivery system allows the Shirane to attack hostile submarines with minimal warning.
The Sea Sparrow launcher is on top of the hanger deck aft of the funnel. The standard twin 4-pod launcher platform is positioned to fire aft, port, starboard or vertically. The Sea Sparrow can engage aircraft or inbound missiles even those of the sea-skimming type. The Sea Sparrow missile is 12 feet long and weighs 510 pounds including a 90-pound warhead. Its inherent range is 10 nautical miles (19 km) and guidance is via semi-active homing radar. Detonation is through a proximity fuse allowing for a 27 foot kill radius.
Two triple ASW (Anti-Submarine Warfare) torpedo launchers are located amidships along the outer edge of the ship at port and starboard. The three tubular units can be rotated out to face the sea for launching and each torpedo is thrown into the water using air pressure. This tried-and-true method of compressed air launching of torpedoes has been a staple of naval warfare since the days of World War 1. Each tube is pre-loaded with a Mark 46 torpedo which are the of the current NATO standard type. Each torpedo weighs 508lbs (231kg) and has a range of 12,000 yards (11km) and can dive to 1,200 ft (365m) when hunting enemy submarines. These weapons use a circular search pattern running at 40 knots (74 km/h) while using an internal guidance active/passive acoustic homing system.
The 20mm Phalanx CIWS is the "last chance" anti-ship/anti-aircraft/missile defense short-ranged weapon system. The radar-guided 20mm Gatling can fire 4,500 rounds per minute and is mounted on a swiveling base, integrated to a radar system aboard for acquiring and tracking of targets up to 3,600 meters (11,800 feet) away from the ship.