The Gabhdán-class Fast Combat Replenishment Ship is the result of the SDF-Navy realizing, that they needed a fast vessel for supply purposes to keep pace with other fast vessels and evolving combat situations worldwide, including the replenishment of troops ashore, if the need should arise, also capable of acting as a command and control vessel for squadrons of smaller vessels, like Fast Attack Craft.
The term gabhdán means either a container or a gulliable person.
The Gabhdán-class Fast Combat Replenishment Ship is a classical monohull-design built in accordance with military specifications, contrary to other replenishment ships, which are basically overhyped freighter designs. Vital areas, for example the bridge and engine rooms, are armoured with light Kevlar Splinter Plating. Constructed with a bow piercing the waves like a hot knife does through butter, the Gabhdán-class Fast Combat Replenishment Ship reaches higher speeds and more economic operation then similarly sized vessels.
With a length of 225.5 metres and a beam of 26.8 metres, the vesssel has a displacement of 30,500 tons full load, 18,000 tons standard, and a draught of 8.3 metres when fully loaded. The Gabhdán-class Fast Combat Replenishment Ship can be loaded with up to 10,000 tons of fuel oil of different kinds, including fuel for jets, 500 tons of fresh water and up to 2,000 tons of cargo and ammunition of various kinds. For more fresh water, the Gabhdán-class Fast Combat Replenishment Ship carries a water-purification plant, which recycles old water and uses sea water to produce drinking water.
For loading and unloading cargo, the Gabhdán-class Fast Combat Replenishment Ship is equipped with four light cranes and two heavy cranes, four lines for replenishment of other vessels with fluids, for example fuel, two each on port and starboard and capable of extending up to twenty metres.
Of the cranes, the two heave ones are aligned with the keel, capable of extending 25 metres with a loading capacity of 50 tons, while the lighter ones are at the side of the main cargo hold, two each on port and starboard, capable of extending 15 metres with a maximum load of 15 tons, including, but not limited to, the lines for fluid replenishment. The cranes can safely operate and be operated in sea state 5, the fluid lines in sea state 6, although we don't recommend that.
Additionally, the Gabhdán-class Fast Combat Replenishment Ship carries a hospital with 150 beds, an intensive care unit with ten beds included, and two small operating theatres, which allow for the same treatment as a normal hospital on shore. The vessel's interior itself is fully protected against the onslaught of nuclear, chemical and biological weapons, including storage rooms for gas suits, airlocks and other NBC-protection equipment. This also allows for operations in more frigid environments.
The Gabhdán-class Fast Combat Replenishment Ship is powered by three Diesel generators, which, in an arrangement known as Integrated Electrical Propulsion, provide power for both the ship's electrical systems, like radars or coffee makers, and the engines, thus saving space, eliminating the need for costly gearboxes and generally lowering the operating costs of the vessel. The generators, two in one engine room near the aft, one in a smaller engine room near the front, produce 97,000 kW of electricity, one of them being enough to power the basic systems of the vessel in case of general failure of the other two generators.
This amount of power suffices to accelerate the vessel to 30 knots, or 55.6 kilometres per hours, while allowing for a range of 8,000 nautical miles, or 14,800 kilometres at a cruising speed of 18 knots. This range can be extended considerably should the fuel in the tanks intended for replenishment be used by the vessel itself.
The exhaust fumes of these diesel generators are funnelled along the vessel and exhausted through one main smokestack, when they have cooled down considerably, thus reducing the vessel's thermal signature. For reducing the acoustic signature, the generators are rested on shock absorbers.
Electronic Warfare and Decoys
The Gabhdán-class Fast Combat Replenishment Ship is equipped with full suites for Electronic Counter Measures, Electronic Support Measures and Electronic Counter-Counter Measures, as well as a number of other, passive defensive systems.
Electronic Countermeasures, or ECM for short, are used to deceive and trick enemy means of detection and ultimately not having a guided missile slam into the ship's side. Be they sonar decoys or radar jammers (Rasberry Jammers is the system we usually use), active ECM measures confuse the enemy's sensors, while passive measures include for example the jamming of the guidance systems of enemy missiles.
Electronic Support Measures meanwhile detect, intercept, identify, locate, record and analyze sources of radiated electromagnetic energy (for example radar) for threat recognition and other purposes, amongst them intelligence information. With these information, a commander can make the tactical and, if necessary, strategic decisions needed. It also provides the means necessary to gather information about the Electronic Warfare Systems of the enemy either in order to avoid an attack or to attack more effectively.
With Electronic Protection (EP), or Electronic counter-countermeasures (ECCM), the ship is hardened against every kind of electronic attack, for example against scrambling and jamming. This allows to attack the enemy even when he feels safe with his jammers in place and activated.
In addition to that, for those enemies or their missiles, which come too close, the Gabhdán-class Fast Combat Replenishment Ship is equipped with a Multi-Ammunition Softkill System, MASS for short. The system connected to the sensor systems, mainly radar, and uses the data to launch radar decoys operating on all relevant wavelengths of the electromagnetic spectrum, confusing advanced, sensor-guided missiles. It can either be operated by a person or operate autonomously.
For less advanced, heat-seeking missiles, the Gabhdán-class Fast Combat Replenishment Ship is equipped with two launchers for chaffs, which will confuse heat seekers and divert them from the vessel.
In case of submarine attack, the Gabhdán-class Fast Combat Replenishment Ship carries a launcher for torpedo decoys.
Sensors and Processing Systems
The Gabhdán-class Fast Combat Replenishment Ship is equipped with several radars, both for finding the enemy and finding the own way. Primarily amongst them are two Nuacht N-12 Mark II Air/Surface Search Radars, multi-function radars operating on X-Band to search for and detect and track up to 350 targets at a range of up to 400 kilometres and a height of up to 9.5 kilometres, also looking up their IFF-Identification. These radars can also double as air-traffic control radars, navigation radars and fire-control radars.
In addition to that, the Gabhdán-class Fast Combat Replenishment Ship carries a Nuacht N-4 Navigation Radar.
For warnings against radar-locks on the own vessel, the ship is equipped with a suite of highly advanced Radar Warning Receivers, warning in case of radar locks, for example by enemy radar guided missiles and thus allowing for countermeasures.
As a measure against submarines and other botherings from beneath the surface, the Gabhdán-class Fast Combat Replenishment Ship is equipped with a bow-mounted sonar.
Most of the armament of the Gabhdán-class Fast Combat Replenishment Ship serves defensive purposes, with the primary defensive load against enemy missiles and aircraft resting on the shoulders of the four Ceantar C-84 Mark II CIWS, which are mounted two on either side of the vessel and capable of covering all angles of approach by enemy missiles with at least one gun, in most cases two. As CIWS, these are the weapon of last resort against incoming missiles, ECM and decoys being primary means. The guns can operate either autonomously, which we recommend, or be controlled manually, both of which is possible due to the C-84 Mark II having its own targetting radar and fire control mechanisms.
The weapon suite is completed by two Ceantar C-44 Mark II 40mm AA-guns, although the term AA-gun is a slight misnomer: While the Mark I was indeed a dedicated AA-gun, the Mark II is a multi-purpose gun, capable of acting against targets both in the air, on the surface and, when in range, on shore. These two guns, one on either side of the vessel between the small cranes, is designed to be controlled by external fire control systems, linked to the radars via the Type 900 Datalink, which provides the data needed for firing adjustments. While that can be done automatically, the gun can also be operated by a gunner using the mounted camera as a 'scope'.
To support the hunt for submarines, the vessel carries two Gráinneog G-321 Mark II Hedgehogs, which are capable of launching the Tormán Mark I shells: Fifteen shells, rocket launched into the general direction of the enemy submarine, each of them carrying a small torpedo as well, which passive acoustically homes into the enemy submarine, penetrating its pressure hull with their payload of twenty kilograms of high explosives - one would be troublesome, two or more would be devastating. Both of them are mounted at the sides of the forward superstructure, one port, one starboard.
Additionally, the Gabhdán-class Fast Combat Replenishment Ship has six 'balconies', positions on the superstructure designed for mounting heavy machine guns or SDY-Gabha SG-1 Mark III autocannons (which will not be included into the normal delivery). Closeby, within the superstructure, are six small rooms with numberpads, which can be used as weapons lockers for the weapons to be used from these positions, in addition to the larger armory in the aft superstructure.
The Gabhdán-class Fast Combat Replenishment Ship comes with a flight deck for two medium-sized helicopters and a hangar for up to five, including a smaller side-workshop for the repair and maintenance of helicopter drones. The flight deck itself is rated safe for vectored-thrust VTOLs.
The command systems for drones, much akin to the ones used aboard the Faoileán-class Drone Carrier, are placed in a seperate room behind the bridge. This allows the vessel to take command of drones patrolling and operating in the area, not only the own, but also the ones launched from further away. The vessel is not equipped to launch or recover fixed-wing drones.
The Gabhdán-class Fast Combat Replenishment Ship is a design older then the more contemporary Port-Hackburry-class Fleet Oiler. In the early 2000s, SDY began with a design study for a fleet replenishment ship for the SDF-Navy, on their request, to enhance the range of the vessels used by the SDF-Navy and thus enlargening the patrol radius of the vessels in question. At the time, it was known as the Pattern 996 Replenishment Ship.
That project was soon abandoned by the SDF, Silverport Dockyards Limited shelving the plans for future references - that future came in 2012, in Marley Bay, when units of the SDF-Navy went into combat during the Halfblakistani Intervention. Many lessons were taught to the SDF-Navy that day, one of which was the esseential role of larger and more capable support ships. The SDF-Navy didn't have any with them due to those, which the Navy had, simply being incapable of operating in a combat environment.
It is doubtful, that the SDF-Navy would have fared any better, if several of the Pattern 996 Replenishment Ships would have been present, but it wouldn't have hurt either way, these vessels enhancing the combat radius of especially the Fast Attack Craft, which played a vital role in breaking out of the pickle the SDF found itself in. Many of the FACs used in that battle had to be taken under tow during the return trip, which had been quite dangerous. So, after the battle, the SDF-Navy went ahead and began a large-scale modernization, one result being the Gabhdán-class Fast Combat Replenishment Ship, the unearthed, updated and finished design of the Pattern 996 - the Gabhdán herself being built as a testbed vessel by and for SDY.
The SDF-Navy has ordered ten of these vessels to replace the Sciath-class Corvettes leading the Fast Gunboat Squadrons, read the FAC-Squadrons, and to assign one of them to each of the Sealgaire-class Helicopter Carriers.