by Max Barry

Latest Forum Topics




by The Dutch Democratic Republic of Knootoss. . 12 reads.

KDF Phlegethon Class [FFG]

This is the design of Knootoss released for export in Royal Beaufort Shipwrights Guild, linearted by The freethinkers

KDF Styx of the Knootian Home Fleet (click the image above to see the high resolution version)

The Phlegethon-class guided missile frigate is a prolific example of one of the older pre-Ondeugd class ships that has been constantly refitted and improved to remain at the core of the Marine of the Knootian Defence Force. These Phlegethon-class vessels play a pivotal role in the protection of Knootian coastal waters, and also undertake ASW roles in Knootian territorial waters and in large maritime battlegroups.

In Greek mythology, the river Phlegethon ("river of fire") was one of the five rivers of the underworld. It flowed with fire that burned but did not consume fuel. In the Divine Comedy the river is made of boiling blood and is part of the seventh circle of hell, containing the shades of tyrants, murderers, robbers and those guilty of sins involving violence against others.

Like the De Ruyter-class Battlecruiser, the Phlegethon recieved initial gate planning shortly before the first Vogels administration, but the design itself only began in production in the second year of this administration. The laissez-faire government sought to replace a large number of old and increasingly outdated coastal patrol vessels and escorts as cheaply and as quickly as possible. The Marine therefore opted for the proposed Phlegethon design as it represented the best balance of capability and cost that would be allowed, and could be easily retrofitted and refitted with new systems and weapons, should the situation change for the worse in the future.

The design of the vessel itself was relatively simple. An all-steel monohull with a double bottom and twelve water-tight compartments for survivability, the Phlegethon was surprisingly tough, and the horizontal main deck and the angular single-block superstructure provided a mildly stealthy outline. The initial weapon, engine and sensor fit was hotly debated, as was the role of the ship itself given the variety of ships the class was going to replace, but eventually budgetary constraints won out and the basic fit, though sufficient, left a significant gap in capability.

For the construction of the ships themselves, each vessel was divided into five 'super-segments' which could be built simultaneously, to reduce production time and save money, and then welded together in a dry dock before fitting out. The modular design of this nature allowed far quicker installation of the larger machinery within the ship (such as the engines and gearboxes) within a shorter time period, and would in the future also allow far more efficient retrofitting of the ship's internal systems. Armour was removed to reduce cost, but a complete damage control and NBC protection system was installed, along with anti-spall liners and a hardened keel. The modular nature of the design allowed heavily damaged sections to be replaced entirely, whilst the thin steel hull could be easily repaired even at sea in the event of an attack.

Armament and Sensors were kept to a minimum, and the lack of committed funding meant very often that ships going out to sea were fitted with different outfits of weapons and electronics. The baseline weapon fit included a 76mm (3 inch) OTO Melara Gun, 2 20mm Phalanx CIWS, an 8 Cell Self Defence Mk.41 VLS, 2 20mm cannons and 2 dual 324mm Torpedo Launchers. Sensors included a decent 2D air/search system, and a hull mounted active and a towed passive sonar array for detecting and engaging submarines.

A hanger and pad for a helicopter were fitted aft, able to launch, maintain and recover a variety of helicopters, but only on ranged deployments were helicopters carried as matter of course on the Phlegethon class due to a lack of money and the aircraft themselves.

Despite these drawbacks, the Phlegethon class proved the underlying excellence of Knootian shipbuilding, and the ships, though underarmed, were excellent seaboats and tough fighters, popular with their crews due to the low maintenance requirements and the spacious and gentle ride they provided. The vessels served their masters well for a number of years, however, as subsequent events proved, an underfunded, undergunned Knootian Marine couldn't hope to complete the tasks and trials required of it.

After a rise in Defence spending, a refit from the original design was proposed and approved.

Refit (Batch II)
The basic design would remain the same, but the extra space for new weapons and sensors was quickly used up as the ships were bought 'up to spec' to be able to compete in the modern warfare environment. The main gun was replaced with a new 127mm model, allowing the Phlegethon class to finally be able to engage land and large surface targets with heavy artillery fire. The old, now-ineffective 20mm CIWS were replaced with more powerful Thales systems.

Two Quad ASM missile launchers were fitted aft of the funnel and the VLS was expanded from 8 to 16 cells along with an increase in the types of weapon avaliable to be carried. This increased firepower was complimented with a brand new 3D Air/Surface search radar and new ECM equipment, allowing the ship to track, engage and destroy more targets at a greater range. Other systems also recieved minor upgrades and new armour plating was added to the design to protect vital areas.

The Phlegethon class, having gone through this extensive refit, are now highly capable and effective ASW and Escort Frigates, able to deploy in both large battlegroups or by itself with relative ease, equipped with a weapon system and sensor package equal to any comparable design.

Technical data

Phlegethon class


126 m


14 m


4.4 m


4,200 t


115 officers and crewmen


1x OTO Melara 127mm/52 D/P Gun
1x 16-Cell Sub Length Mk.41 VLS (VLA, ESSM, SM-2)
2x Quad Launchers for Boeing 'Harpoon' Block II SSM
2x Thales Naval Goalkeeper 30mm CIWS
2x Oerlikon 20mm Cannons
2x Twin Eurotorp 324mm SD Torpedo Tubes


Thales SMART-L 3D air/surface search
2x Mk. 99 SAM control FCS
Thales PHS-36 Hull-mounted Active Search, housing for towed array


Thales M40A Combat Management System as standard. Command and Control is also to be enhanced by a follow-up to the old CAESAR system developed by Caesar SuperComputer Inc The software for the CAESAR 2.0 computer system is to feature revolutionary new capabilities.


Falltech Mk603 ECM Suite
1x AN/SLQ-25A 'Nixie' Towed Decoy
4x 16-Cell Decoy Launchers, Flares/Chaff


Combined Diesel And Gas Turbine arrangement
2x Thales/Thompson C1400 Diesel Turbines for main drive
1x Thales/Thompson C2600 Gas Turbine for high speed running
38,000 total SHP driving two five-blade, variable-pitch propellers

Flank speed

29 knots

Cruise speed

16 knots


8,500 km @ 16 kts ave.


3mm steel spall liners (1st). Retrofitted with light steel and composite armour schemes for vital areas and new structural bracing