Jade-class naval gunfire support ship

The Jade-class is a class of nine Invenian Navy naval gunfire support ships (GS) designed for shore bombardment missions. Armed with 8-inch guns in two two-gun turrets or heavier armament, they are the heaviest-armed ships in terms of gunnery in the Invenian Navy. The last ship of the class, USIS Sapphire, has a modified armament with the 15-inch/L45 Mark 3 single-gun turret replacing the front 8-inch two-gun turret. As the classification suggests, the class is not designed for naval combat. The class has since been autonomously operated after a major refit in 2019.

In some unofficial publications, the Jade-class is also referred to as the Gemstone-class.

Characteristic

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The Jade-class was the first class of ships to feature guns with calibre larger than 127 mm since the retirement of the last gun cruiser, USIS Mille in 1980. However, unlike the conventional designs of heavy and light cruisers, the Jade-class prioritized protection solely for the turrets, lacking overall armour. The Jade-class is also slower than traditional gun cruisers, at 24 knots compared to 30 knots since the Jade-class were meant to operate with the amphibious fleet rather than the main fleet.

The Jade-class's primary weapon is the autoloading, rapid-fire 8-inch/L60 Mark 16 guns. They were the first autoloading 8" developed by the Invenian Navy with the help of the Invenian Navy, doubling the rate of fire of previous designs to ten rounds per minute per barrel. The Mark 16 gun is capable of firing different types of shells, such as HE, AP, special HEAT and guided shells. Guided shells are most commonly used because they are far more accurate than unguided shells and have more than double the range (85km). Elevation of the turret ranged from -5 to +65 degrees.

The last ship of the class, USIS Sapphire, had its armament modified with its fore turrets replaced by a 15-inch/L45 Mark 3 single-gun turret as a technology testbed. The 15-inch/L45 Mark 3 was upgraded from a spare 15-inch/L45 Mark 2 barrel for the Liwich-class fast battleships thus many characteristics of the Mark 3 are shared with the Mark 2. A major alteration from the older guns was the autoloading system on the Mark 3, allowing a significant increase in the rate of fire to 3 shells per minute. The new Mark 3 turret can be elevated to a maximum elevation of 50 degrees. However, since all of the 15-inch shells were decommissioned and disposed of following the decommissioning of the Liwich-class fast battleships, the shells have to be reinvented entirely. New HE and AP shells were developed, however, the development of the ambitious guided or rocket-assisted shells was cancelled due to cost concerns, resulting in an inferior range compared to the 8-inch/L60 Mark 16 guns using guided shells. As a consequence, the 15-inch/L45 Mark 3 was not installed in any other ships at least until the development of guided 15-inch shells in the future. In addition to guns, the ships also feature a twin land-attack missile launcher, allowing standoff strike capability.

The ships' defensive weapons are a Topaz gun/missile close-in weapon system and short-range surface-to-air missiles: one SAM-13 "Stubborn" launcher containing 9 missiles and one SAM-14 "Silver" launcher containing 8 missiles. To save space, the launchers are positioned on top of the fore and aft turret. In addition, they are equipped with a corner reflector decoy system as well as one decoy launcher.

Due to the vulnerability of this class, it was the first class of ships to be scheduled for conversion to unmanned surface vessels (ASV) under the COMPASS conversion in 2019.

Development

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Origin
After the retirement of the last gun cruiser, USIS Mille in 1980, debates regarding the role of naval surface fire support (NSFS) intensified. "Reformers" factions within the Navy and the Marine opposed the decommissioning of USIS Mille and request the reactivating of the ships along with the Liwich-class fast battleships; or the development of a new class of battleship to fulfil the NSFS role. The Navy pointed out that reactivating the Liwich-class fast battleships or developing a new class of battleship would be prohibitively expensive, while the Naris-class heavy cruisers are too obsolete to be reactivated. The debate was heated to the point that the Navy publicly ridiculed the idea in 1982 with the battleship design contest on April Fools, which has since then become an annual tradition. This led to public scrutiny and complaints that the Navy had not been in good faith considering the potential of battleships in naval combat or in providing NSFS. In June 1982 the Parliament requested the Navy to initiate a study for potential new ships to fulfil the NSFS role with gun calibre of at least 6-inch (155mm). In 1985, the Navy announced that it would not build new battleships or gun cruisers to fulfil this role; but rather small specialized ships carrying high-calibre turrets. Development and testing with guns of various calibre began in 1986 at the Opemc Proving Ground in Neodyl with the help of the Invenian Army. In 1988 the prototype 8-inch/L60 Mark 16 gun based on the 8-inch/L60 Mark 15 of the Naris City-class cruiser was chosen as the primary weapon of the ships. The Navy contracted Norjen Ship System for the design of the gunfire support ships, resulting in a 6000-ton design armed with four 8-inch/L60 Mark 16 guns. However, the project was delayed again after the Parliament request the use of the 15-inch barrels in storage as potential technology demonstrators for the last ships of the class. The Navy obliged and began a joint development with the Army to develop the 15-inch/L45 Mark 3 with new shells. development was completed in 1992 and nine ships were authorized, with the last ship carrying the 15-inch/L45 Mark 3 experimental turret.

The first ship of the class, USIS Jade was laid down in 1999, launched in 2000 and commissioned in 2002.

USIS Sapphire modification
USIS Sapphire, the last ship of the class, was commissioned with a fore 15-inch/L45 Mark 3 single-gun turret instead of the 8-inch/L60 Mark 15 two-gun turret as a technology demonstrator. Due to the limited range because of the cancellation of rocket-propelled shells, the proposed followed-up to the ship was cancelled. Nevertheless, the 15-inch/L45 Mark 3 was considered effective in shore bombardment.

USIS Sapphire was laid down in 2001, launched in 2002 and commissioned in 2005.

Project COMPASS conversion
The Jade-class ships have long been criticized for their lack of armour, earning them the nickname of "floating powder kegs". As such, when Project COMPASS come online in 2018, the Jade-class ships were the first ships considered for conversion. In addition, the ships' sensors and processing systems were replaced with newer-generation technologies. The conversion/refit took an overall 3 years to complete, shorter than other ship classes because of their size and their role as gunfire support ships rather than surface combatants.

Ship in class

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Name	Hull no.	Builder	Laid down	Launched	Commisioned	Home port	Status
Jade	GS-1	Sanaii Heavy Industry	1999	2000	2002		Active
Diamond	GS-2	Sanaii Heavy Industry	1999	2000	2002		Active
Topaz	GS-3	Naris Shipbuilding	1999	2000	2002		Active
Onyx	GS-4	Naris Shipbuilding	1999	2000	2002		Active
Ruby	GS-5	Howe Navy Yard	2000	2001	2003		Active
Garnet	GS-6	Howe Navy Yard	2000	2001	2003		Active
Amethyst	GS-7	Sanaii Heavy Industry	2001	2002	2004		Active
Emerald	GS-8	Sanaii Heavy Industry	2001	2002	2004		Active
Sapphire	GS-9	Naris Shipbuilding	2001	2002	2005		Active