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JS Osumi (LST-4001)

1998 MODERN NAVY

JS Ohsumi (LST-4001) Story

As an island nation, Japan has always had to rely on a strong navy in its military structure. This is as true today as it was during World War II (1939-1945), when the Imperial Japanese Navy (IJN) proved to be a formidable and formidable enemy.

The modern Japan Maritime Self-Defense Force (JMSDF) is a far cry from its bellicose IJN days, but it is still a well-made and capable forceboth on the water and under the sea.

To support potential future amphibious operations, especially in the many island groups now challenged by China and other regional neighbors, the U.S. Navy has invested in three Osumi-class battleships ("Oosumi") to assist with "tank landings" "Service Ship" (TLS)/"Landing Dock" (LSD) role.

These ships are extremely important to amphibious operations as they can launch land combat forces from offshore positions and help establish and control strategically important beachheads. Only a dozen countries use these specialized ships, with the United States leading with 11 (San Antonio-class).

What's interesting about the Ohsumi-class ships is that their classification as "armored landing ships" is somewhat misleading, as they lack the bow-mounted, oversized, clamshell doors and associated unloading ramps, which are It is common when used for similar types and boarding vehicles. As such, the Osumi class does not "strand" its troops in the traditional sense, but rather its primary capability is to act as various sea docks, release vehicles and launch helicopters. This certainly limits the tactical value of the class, but makes sense given that the Japanese constitution after World War II restricted certain defensive construction projects.

In fact, the Osumi class was originally designed as a compact aircraft carrier for defensive operations, but the local political climate in Japan at the time (early 1990s) changed the design to be an amphibious support ship rather than an amphibious assault ship.

The end result is a warship that looks like an aircraft/helicopter carrier, but lacks many of the capabilities of both types. Its general shape was conceived as a pointed toe and square stern, with partially unobstructed foredeck and aft decks. The island's superstructure is identical to the midship and offset on the starboard side, while carrying the communications, sensors and radar systems common to modern warships.

It carries the OPS-14C series air search radar, as well as the OPS-28D surface search unit and OPS-20 navigation kit. Four Mark 36 SRBOCs (Super Rapid Blooming Outboard Countermeasures), tubular chaff and decoy launch systems form part of the ship's important countermeasures. It is possible that the crew complement number 138 with a typical infantry detachment of 300 men.

For humanitarian missions, the interior of the ship can be converted to provide medical supplies and sleeping/resting areas if needed.

The overall dimensions of the

class ship are 178 meters in length, 25.8 meters in beam, and 17 meters in draft. Displacement reaches 8,900 tons under standard load, increasing to 14,000 tons under full combat load.

While no lift decks or hangar facilities were installed, part of the ship's aft surface was reserved for a pair of Navy/Navy medium lift helicopters. This confines the helicopter to the ground, and the unit must be kept safe during transport as they offer no protection. All work on the helicopter must also be done on it.

Typically, these spaces are reserved for 2 Boeing CH-47 Chinook medium lift helicopters in service with the Japanese Navy or navy - although retrofit work is underway to carry updated Bell Boeing MV-22 Ospreys - Able to accommodate tilt-rotor transport.

The island superstructure is preceded by a single-level elevator that leads to the lower deck, which accommodates vehicles, infantry, and landing craft. At the stern of the hull is a large loading and unloading ramp for releasing vehicles and boats into shallow waters.

The warship can accommodate and launch two fully loaded Landing Craft Air Cushion (LCAC) amphibious hovercraft, which can help strengthen Japanese positions by transporting up to 10 main battle tanks (MBTs) and up to 1,000 troops.

Installed power includes 2 x Mitsui 16V42M-A marine diesel engines with 26,000 hp on 2 x axles. A single bow thruster is used for fine adjustment. Under ideal conditions, the boat can go 22 knots at full speed.

The three Osumi-class ships are JDS Osumi (LST-4001), JSD Shimokita (LST-4002) and JDS Kunisaki (LST-4003). The former pair was built at Mitsui Shipyard in Tamano, while the latter was completed at Hitachi in Maizuru from 1995 to 2000. Currently, all of them are assigned to Landing Division 1 in the important (and famous) Japanese naval port of Wu. The lead ship JDS Osumi was laid on 6 December 1995. She was launched for sea trials on November 18, 1996, and officially commissioned on March 11, 1998.

At this time (2018) all ships are in service.

To date (2018), this class has been used for reconstruction and humanitarian use following the devastating 2011 Tohoku earthquake and subsequent tsunami that killed nearly 16,000, injured over 6,150, and killed over 2,500 Work ignores summons. To improve the amphibious assault doctrine while constitutional restrictions are eased, the Japan Maritime Self-Defense Force has invested in the Hyuga-class helicopter carriers (described in detail elsewhere on this site) and will likely require the United States to purchase a special class of amphibious assault ships, the Wasp.

All of this is no doubt focused on preventing or countering further Chinese actions in the region's disputed waters and islands.