Creachadóir-class/Predator-class Anti-Submarine Corvette

## Predator-class Anti-Submarine Corvette

### Propulsion

Integrated Electric Propulsion, 3x Diesel Generators, 4000 kW each, two water jets

### Range

3,000 nmi (5,600 km) at 14 knots (26 km/h)

### Sensors and Processing Systems

1x Air/Surface Search Radar, 1x navigation radar, Radar Warning Receiver, 1x Variable Depth Sonar, 1x Magnetic Anomaly Detector, Type 900 Datalink

### Decoys

Multi-Ammunition Softkill System, Torpedo Decoy System

### Armament

2x 30mm CIWS, 1x 40mm AA-guns, 2x hedgehogs, 1 quadruple 533mm torpedo launcher, 2 rails for mines and depth charges

### Aviation Facilities

Flight deck, hangar, drone control room

The **Creachadóir-class Anti-Submarine Corvette**, or **Predator-class Anti-Submarine Corvette** for the international market, is a small and relatively cheap ASW-corvette developed by SDY for export to smaller navies as a viable tool in anti-submarine warfare, or for larger navies as a handy small vessel to conduct ASW-patrols in the own waters. The Creachadóir-class Anti-Submarine Corvette is designed for both active submarine hunting as well as escorting both trade convoys and larger vessels and fleet groups.

The term *creachadóir* means predator, as in a predatory animal, hence the name for the international market.

## Design

The Creachadóir-class Anti-Submarine Corvette is a classical monohull-design, displacing 1,050 tons at standard load, 1,200 tons at maximum load. The vessel is 81.68 metres long, with a beam of 9.8 metres and a draught of 3 metres at standard load. This allows for operations from nearly every harbour in the world, capable of operations both in Blue and Brown Waters, high-seas and coastal areas.

With a range of 3,000 nautical miles at 14 knots, or 5,600 kilometres at 26 kilometres per hour, and a maximum speed of 30 knots, 55.5 kilometres per hour, the Creachadóir-class Anti-Submarine Corvette is capable of hunting down enemy submarines, as well as keeping pace with most warships and trading vessels.

As with most of the newer vessels of SDY, and nearly all military vessels of SDY, the Creachadóir-class Anti-Submarine Corvette is build with stealth measures in mind, but no dedicated stealth vessel. Inclined flanks bounce off radar beams into the unknown, away from the receiver, while parts of the superstructure, such as the anchorhouse and stairwells, are placed inside, further reducing the radar cross-section to that of a far smaller craft.

The thermal signature is reduced by the exhaust gases being channelled through smaller pipes to cool off before being released through three small exhausts, making the vessel's thermal signature smaller. The producers of that exhaust, the diesel generators, are rested on shock absorbers, which reduce the acoustic signature considerably, which helps with both not being detected by enemy acoustic detection measures and detecting enemy acoustic signatures, for example from submarines. The Creachadóir-class Anti-Submarine Corvette is built using non-magnetic steel.

The Creachadóir-class Anti-Submarine Corvette can not carry or support a helicopter, but has a small flight deck for medium sized helicopter-drones, as well as a hangar to maintain and store them. Additionally, a control room for helicopter drones is placed near the bridge, using a system and installation bearing striking resemblance to the ones used aboard the Faoileán-class Drone Carrier and with similar capabilities (however, the Creachadóir-class Anti-Submarine Corvette can not launch or recover fixed wing drones).

### Propulsion

The Creachadóir-class Anti-Submarine Corvette is powered by three diesel generators, which provide 4,000 kW each, the same generators as onboard the Spéirling-class Fast Attack Craft. These generators provide power for everything aboard the vessel, be it the radars, the engines or the coffee makers, arranged in a dispersed fashion: Two generators are in the main generator room aft, while the third one is close to the bow in a separate engine room. This engine arrangement, called Independent Electric Propulsion or IEP for short, reduces maintenance cost considerably, as gearboxes and their needs of maintenance are simply not necessary, as well as all the power aboard being provided by one system.

The Creachadóir-class Anti-Submarine Corvette is capable of limping back to harbour on only one of these generators, if need should arise. Noise interference and vibrations from the generators are low as well, mainly due to the stealth measures taken: The shock absorbers not only reduce the noise the vessel makes, they also add to crew comfort by eliminating this source of noise almost completely.

Two water jets, or more technical pump jets, propel the vessel forward with a maximum speed of 30 knots or 55.5 kilometres per hour. Although a bit more expensive then conventional propellers, the water jets are both more silent and the blades themselves are better protected against debris and other stuff floating underwater, as well as more silent. Reversing is done by the addition of a reversing bucket, adding to the manoeuvrability of the vessel, while manoeuvring itself is handles with the water jets themselves via thrust vectoring. This also allows for higher speeds during heavier sea states.

### Electronic Warfare and Decoys

The Creachadóir-class Anti-Submarine Corvette is equipped with an arrangement of systems for Electronic Warfare and decoys to defend itself against the enemy without bringing the weapons to bear, the first layer in the defence of every warship.

Core of these systems are both the ECM-Suite and the Multi-Ammunition Softkill System, MASS for short, acting against above-surface threats. The ECM-Suite provides the capability for Electronic Countermeasures, meaning capabilities to deceive and trick enemy means of detection and ultimately not having a guided missile slam into the ship's side. With radar jammers (Rasberry Jammers is the system we usually use), active ECM measures confuse the enemy's radars, while passive measures include for example the jamming of the guidance systems of enemy missiles.

The MASS is 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 the defence against torpedoes, the major system is the dispenser for torpedo decoys, which generate a sonar signal, for example engine noise, for the torpedo to lock on instead of the vessel, which is especially effective against passive sonar guided torpedoes. Against active sonar guided torpedoes, the system receives amplifies and sends back the pings send out by active homing torpedoes to confuse the sensors by appearing as a larger vessel. The system, called the Lacha Chluana Mark III, is a fibre-optic towed array on a drum winch to bring the array back to the vessel in case of non-use, and incorporates a small sensor unit to detect incoming torpedoes.

### Sensors and Processing Systems

The Creachadóir-class Anti-Submarine Corvette has a wide array of sensors at its disposal in order to detect sub-surface vessels of any kind and size. Core of that suite is a variable-depth sonar, a Nuacht N-81 Mark II VDS, capable of detecting submarines at a distance of up to 150 kilometres at an accuracy of less then 100 metres at maximum range. It is capable of operating in very rough seas as a system for passive and active surveillance 360 degrees around the vessel, analysis of any received signal (and keeping apart, if it is a whale or a submarine), audio output and includes a torpedo alert. Hanging at a single tow line, the Nuacht N-81 Mark II VDS can actively send out pulses while passively detecting sounds made underneath the surface as well in every direction.

The other system for the detection of sub-surface threats is a magnetic anomaly detector – while the system is usually used aboard aircraft, the MAD can also work in a vessel. The principle is rather simple: Every submarine, be it diesel powered or nuclear powered, even when built of non-magnetic materials, creates a magnetic moment displacement, which is detectable. Additionally, every submarine has bits of magnetic materials, be it in diesel engines or nuclear reactors and many other systems, which can be detected.

To detect targets above the surface, the Creachadóir-class Anti-Submarine Corvette is equipped with a proven and capable Nuacht N-12 Mark II Air/Surface Search Radar, an X-Band Radar. This radar, used onboard many of SDY's smaller vessels, like the Scoth-class Corvette, can detect objects from 400 kilometres away, at a maximum height of 9.5 kilometres.

Another radar aboard is the Nuacht N-4 Navigation Radar, used to find the way.

For the detection of incoming radar impulses, for example of enemy warships or aircraft or even incoming radar-guided missiles, the Creachadóir-class Anti-Submarine Corvette is equipped with a Radar Warning Receiver. Other sensor systems can be employed by the Helicopter-Drones.

The Type 900 Datalink is a system for Duplex Communication in both directions in real time, processing said data in real time as well. Not only sensors and weapons are connected by this system, but virtually everything onboard the ship, from consoles on the bridge to the mobile coffee maker by the helipad. Personal Computers and gaming devices of the crew use another system, utilizing a satellite uplink and being diconnected from the Datalink in every way, shape and form imagineable.

To exemplify the processing power of the Type 900 Datalink: When the first prototype of the Type 900 was supposed to be tested, the corresponding department in Laclan hosted a LAN-party with roundabout ten thousand participants (4,157 at height) playing 25 different games - with the 'Local Area Network' reaching across the entirety of the Free Lands with no lags whatsoever.

### Armament

The Creachadóir-class Anti-Submarine Corvette is equipped with a wide array of weapon systems, most of them geared towards the defence of the own vessel and the attack against sub-surface targets.

For attacking targets far above the surface, the Creachadóir-class Anti-Submarine Corvette is equipped with two 30mm CIWS, Ceantar C-84 Mark II, one on starboard, one on port. The C-84 Mark II is equipped with their own little targeting radar, operating fully autonomously against incoming missiles and aircraft coming too close for mutual comfort. This results in said target, usually a missile, being shredded by 30 millimetre bullets.

Mounted on the bow, the Ceantar C-44 Mark II 40mm AA-gun is not only an AA-gun, but also a multi-purpose gun, capable of acting against both surface targets and airborne targets, including missiles (although it is not effective as an auxiliary CIWS). While guns of this type can operate independently with the aid of a fire control radar, the C-44 aboard the Creachadóir-class Anti-Submarine Corvette can use the Nuacht N-12 in that function, but we recommend setting it to manual control and let an operator remote control the gun with the mounted CV-cam as his scope.

Mounted on either side of the superstructure, the Creachadóir-class Anti-Submarine Corvette is equipped with two Gráinneog G-321 Mark II Hedgehogs, capable of firing the Tormán Mark I shells: Fifteen shells are rocket launched into the general direction of the detected enemy submarine, but each of these shells now carries a small torpedo, an passive acoustic homing little weapon optimized for attacking submarines, penetrating their pressure hull quite effectively with 20 kilograms of high explosives. One will only cause problems for sure - two or more are a bit more difficult to handle.

Mounted at the rear on a fixed mount is the longer ranged weapon against submarines, the Feadán Fe-32 Mark II 533mm Quadruple Torpedo Launcher, differing from the Mark I, as it used aboard the Rhiannon-II-class Frigates only by the addition of one barrel. The torpedoes are launched by compressed air, out aft into the sea.

Last, mounted at either side of the torpedo launcher, but definitely not least, are the two rails for mines and depth charges, which can be dropped either manually or using the automated system. Up to 20 normal-sized naval mines can be loaded for each rail within the standard load-out of ammunition.

## History

Ever since the invention of the submarine, the question had always been how to counteract them – merciless battles were fought by submarines, both against surface targets and sub-surface targets, for the own survival. With the end of World War II, the famous Wolfpacks made way to independently operating submarines with many roles, from fighting ships to ending the world.

Warfare against submarines, ASW, became more and more important to the planners of navies and wars, both on the defensive and the offensive, and defending against submarines became more and more of an issue. Silverport Dockyards Limited realized that a long time ago: One of the first military designs of SDY, following the Sciath-class Corvette's Construction Contract, was the Práta-class Corvette, a dedicated ASW-Corvette, which was never built, despite being a sound design and a foundation for the Creachadóir-class Anti-Submarine Corvette.

It took a while, the SDF-Navy preferring multi-purpose vessels and SDY not yet exporting in major quantities, until Yard 15 took the matter up again as a side-project - and in early 2017, they presented a design, which became the Creachadóir-class Anti-Submarine Corvette, a vessel primarily for the export to foreign countries or two mercenary groups, like the Bristeach Company, which acquired two boats in 2020.