Marathon-class heavy cruiser (EXverse)

The Marathon-class heavy cruiser - hull classification symbol CA - is a class of cruiser in service with the UNSC Navy. Originally built to replace Halcyon-class light cruiser, it became a common sight in human space both during Insurrection and Human-Covenant War due to be built in hundreds of examples thanks to its good firepower and little expenses.
After having commissioned Halcyon cruisers, the Navy was dissatisfied by costs and the lack of modularity of these vessels, so Sinoviet shipyards took advantage of the situation and proposed the Marathon-class which, at the time, was known as Leviathan-class; starting with six prototypes in 2513, they took part to the Operation: TREBUCHET, where they showed a massive firepower, however Naval Command wasn't very convinced about. After some modifications made during the following six years, finally the now-known Marathon-class entered in full production, with the first of the class entering in service in 2520.
Since the start of the Human-Covenant War, Marathons found themselves lacking the necessary firepower and protection to battle Covenant counterparts, showing only some successes against destroyers and frigates. So, Sinoviet Heavy Machinery laid down an improved version in the late 2527, later dubbed as Block II: until the end of the war, a total of four major upgrades, and a minor one, were produced by Sinoviet.
In 2535 Covenant fleets began to push into Inner Colonies, so Marathons and other large ships were reassigned to their defense. This meant that only a handful vessels between Block IIIA and IV could survive the war, after which the Navy introduced the new Autumn-class with the goal to replace Marathons. However, since post-war times were troublesome, Naval command decided not decommissioning Block IV cruisers, lengthening their service, while Block IIA were scrapped as they were outdated by then.
== History ==
=== Development ===
After building Halcyon-class, many officers were dissatisfied by costs, inadequate firepower and lacking of tactical viability, while only a few glorified its incredible protection. As such, Robert McLees decided to develop another cruiser, but less expensive and more modular than Halcyon, capable of assuming many roles.
With the goal to keep costs low, McLees reused much of the design with which he had created Halcyon-class, as well as it put aside the expensive honeycomb structure, creating in 2509 a purely escort vessel emphasizing anti-air cover; but while the forward head profile and large engine segment protected by armor cowlings were similar but not yet identical, some minor redesigns in the next two years led to a hull's stretching of around twenty meters and they featured a streamlined inwards-slanted underside, which took place one of the two hangar bay, while the other was placed on the prow. Weapon systems were also expanded, adding one MAC gun, much more missile pods and a vast anti-air guns array. Even so, the specialty of this draft was its modularity, as it was capable of removing all missile pods and cargo bays with ease and add other hangars, increasing starfighter capacity.
This draft was completed around March, 2512, and was presented to Naval Command for evaluation tests. It showed good promises, but the modularity and cheap costs were appreciated particularly. Also, many looked interested at the double bridge and space for additional fifty sailors or other people, which could potentially made Marathons a good flagship for all types of task forces, while its ease production and low upkeep cost could allow the Navy to ordered hundreds of vessels.
Two weeks later Reyes-McLees Shipyard were awarded 431 ships. One year later UNSC Marathon entered service.
=== Insurrection ===
Marathons became immediately a mainstay of UNSC fleets for a number of reason. Admirals often choose a Marathon as their flagship to the detriment of and supercarriers, considered them too large or they were unavailable. Captains too considered the command of one of these cruisers as the ultimate step of their career, despite commanding supercarriers or carriers were, at the time, far more ambitious. Its little requiring of maintenance meant that UNSC could spent few credits to operate them, while having a firepower not reachable by the most powerful rebel ship.
As such, Marathons were quickly employ by UNSC Navy in Operation: TREBUCHET and many other invasion during Insurrection, outgunning every rebel ship and gaining almost immediately orbital and space supremacy. Their effectiveness was so high that plans for previous were reviewed: initially expected to put in reserve by 2520 and scrapped by 2524, Naval command decided to put the class in reserve already in 2517, forseeing to scrap it by 2521. Plans modified once again in 2525, when the Covenant revealed themselves.
A changed occurred in 2518, when UNSC Navy decided to awarded Reyes-McLees a hundred of light carriers derived from Marathons. While Marathons themselves were already capable to be reconfigurable into light carriers, Naval Command needed ships without modularity but capable of ferrying troops and logistics at the same upkeep costs of the heavy cruisers, avoiding in this way the use of much large carriers and supercarriers. This choice made debates, as Naval Command didn't release a RFI open to all spacecraft manufacturers, which was provided for law. Despite this, a year later the was commissioned.
By the start of 2525 Reyes-McLess shipyards completed orders of both Marathons and Resolutes.
=== Human-Covenant War ===
The War that started in 2525 proved that, while Marathons had one of the best MAC gun of the early war, it was outgunned by Covenant counterparts and, in some cases, even by Covenant destroyers. Since the Second Battle of Harvest, Marathons found that the modest armor was completely inadequate against plasma fire,reactors weren't enough powerful to recharge MAC guns in a short time and its impressive arsenal of missiles was useless against energy shielding; besides this, its direct counterpart, the , outgunned it in every aspect, and often it was needed two Marathons to destroy a single CCS, numbers too high albeit the Navy could fielded a huge quantity. Despite this, Admiral Cole was the only one, until the advent of 2530s, to used Marathons as long-range artillery, using faster frigates and destroyers to distract and flanking Covenant ships.
So, already by the end of the 2525, spouses McLees got to work to upgrade Marathons and, at the same time, find alternatives with which fight Covenant on the same level. Reyes designed a which entered production in 2527: the Liberty-class had two super-heavy MAC guns which overperformed related to its size, increasing UNSC fleets' firepower but without increasing costs and granting a constant production rate.
McLees, on the other hand, improved the twelve years old-Marathons, giving life to Block II: this version, which was produced in 332 vessels until 2530, featured new engines, the new Titanium-A2 armor and a new targeting system. Vice Admiral Cole was the only flag officer not to used this version, as he managed to attenuating casualty rating and maximizing their performance beyond their actual capacities.
However, Covenant invasion appared to be unstoppable. Many Marathons Block II were lost at an impressive rate, forcing McLees and Reyes to designed another Block. On the third version were implemented a new engine, based upon the Block II one, and new weapon systems Streak anti-air missiles were replaced by Howlers anti-ship missiles, so switching its duties from anti-air to anti-ship; what is more, this change forced the Navy to modify complement carried, as these weapons required more space for ammunitions. Third block worked very well starting with the Battle of Jericho, much more when some captains and admirals starts to layered Titanium-A with other heat-resistant materials, as Cole did from the start of the war to its flagship. Many Marathons Block III were used by Vice Admiral Cole in his Third Fleet, and again in Battlegroup India during the climactic Battle of Psi Serpentis, where the UNSC Io was presumably used as a coverage while the Everest made an emergency slipspace jump inside Viperidae core. Marathons Block III were also used in many battles during the Massacre of Outer Colonies, but by 2536 all capital ships including cruisers were reassigned to every Inner Colony to protect them, fighting almost every last stand until the end of the war fifteen years later.
Block IIIA ruthless ended in 2546 when Camber was destroyed. As that colony was a major Navy manufacturing hub, its loss meant that many materials UNSC ships were built with were no longer available in a short time, which forced Reyes-McLees shipyards to suspend production. Before retiring, Reyes and McLees, at an old age, laid the ground for their successors by help them to design and build Block IV version, which also featured the first plasma torpedo countermeasure, the Protector system. However, due to resources shortage and the lacking of new systems of all sort, only sensor, targeting and navigation matrices were upgraded, so this version was officially dubbed as Block IIIA, despite the Protector system. This version, anyway, was produced for four years, up to 2546.
Before retired, spouses McLees helped to conceived Block IV, which they considered the last version, as the design was almost forty years old. This Block featured a new Series V CODEN translight engine, upgraded weapon systems and the latest A3 armor, which further ehnanced combat capabilities: a new couple of MAC guns, new anti-air guns and new Howlers which made Marathons capable of directly engaged a and potentially win. However CCS remained always a stumbling block, even if with some tactical inspirations it could theoretically win in a two-way fight.
By the time of the Battle of Sigma Octanus IV in 2552 only twenty Marathons Block IV were still active in FLEETCOM Sector One, but many more were under construction on Reach. Among them, UNSC Leviathan was the flagship of Vice Admiral Stanforth during later years of the war, and it fought at least three major battle starting from 2551 until the Fall of Reach on August, 2552. In the biggest battle of the war many uncompleted Marathons took part, by using their MAC systems to augmented Epsilon Eridani's fleet firepower. However UNSC forces capitulated and the colony was lost, forcing RMS to stop production.
At least eight Marathons were present at the Battle for Earth, as a part of the Fifth Fleet, of which fleet UNSC Canberra was the leading ship; many others were part of the larger Home Fleet; other four were above the vital world of New Carthage.
=== Post-War Years ===
Overall 29 Marathons survived the war. Eleven were part of Block IV and they continued to serve in the Navy until the complete introduction of Autumn-class, while Block IIIA's cruisers were decommissioned and scrapped as they were considered outdated. One cruiser, the UNSC Defiance, was the flagship of admiral Graselyn Tuwa and it took part to rescue operations above Gao.
== Specifications ==
=== Hull ===
With a length of 1,192 meters, a width of 293 meters and a height of 375 meters, the Marathon-class dwarf every UNSC destroyer and frigate, however it is dwarfed by every Covenant cruiser class except the CRS-class light cruiser, which in reality is not properly a cruiser. As the successor to the Halcyon-class cruiser, Marathon-class has a similar profile, with a forward 'head' and large engine segment protected by armor cowlings, yet are not identical and feature a streamlined inwards-slanted underside.
Two hangar bays are fitted, one of which is the located on the streamlined inwards-slanted underside, while the other is placed on the prow. As well, two bridge are located throughout the hull: the primary one, located underside amidship, host the ship's command crew, while the other, located on the stern, can host an admiral and his or her staff; otherwise, the second one can be remodeled as a recreational facility for sailors and non-commissioned officer.
Located amidships there is the famous Hell's waiting room, a large room which host sixty SOEIV drop pods used by ODSTs as well as a large holotable, to be used to plan missions; near this facility there are quarters reserved to both ODSTs and regular marines, next to which there are an armory. Other two armories are located throughout the ship, one next to the locker room and cryo-bay, while the other is near the engine room. The ship also host a large and well equipped kitchen, a luxury always present on capital ships, and a permanent recreational area reserved to officers located near the primary bridge.
Crew quarters are single and small but so livable, while the command crew has access to quarters much larger, having also a desk and a chair. The number of upgraded quarters are in excess in relation to the command crew's size, as the ship can host fifty additional personnel: so, when the ship do not carry additional personnel, these quarters are not seized by anyone, although the commander can allocate them to NCOs or sailors if they make request.
191 centimeters of Titanium-A1 armor are fitted onto the hull. The A1 was the first variant developed and, as such, it performed poorly against plasma fire, even this thickness was one the thicker armor installed at the time: while pulse lasers cannot penetrate the armor, plasma torpedoes can easily fuse the armor, leaving the superstructure unprotected. At least two torpedoes are necessary to melt two meters of Titanium-A1, so a third one can easily destroy a Marathon-class cruiser.
From Block II to IIIA was implemented the new A2 variant, which could be also layered with others element reinforcing, in this way, the armor against specific weapons. During the war many captains and admirals layered the A2 with many heat-resistant capability materials, like tungsten or tantalum, otherwise refractory compound such as the tantalum hafnium carbide. These hand-made modifications later inspired the new A3 variant, which was fitted on Block IV's version, improving Marathons protection against directed-energy weapons.
=== Propulsion system ===
The Seven Stars Naval Manufacturing Warhammer 3 is the engine installed aboard Marathons. This engine system is made up of two primary engines which are integrated by further four smaller reactors. This fusion drive was not advanced at the time, as in order to contain costs Seven Stars decided to use the Warhammer's old, but reliable, architecture. Four smaller reactors don't work always, but they activate themselves when extra-power is needed. As such, commanders can ordered to increase power up to two hundred percent, allowing the ship to move as fast as a heavy destroyer for almost five minutes. However, the mass of the ship make it not so agile, despite such reachable output.
With Block II Seven Stars introduced a completely new engine: the Wildfire I had the same architecture of the previous Warhammer, with two primary engine and four smaller reactors; however it had a new cooling system and a new way to generate the output requested to move the ship. This allowed the class to be faster during cruise speed, so keeping the pace with destroyers without activating smaller engines and, thus, and saving fuel. Wildfire II, features on Block III and IIIA, is even more powerful, while Wildfire III has an upgraded cooling system.
The SFTE Series IV CODEN Starlight Naval Company SL-A is the slispace engine fitted onto the class, capable of moving the ship at 2.85 lightyears per day. This translight engine was implemented on all blocks except Block IV, which features a Series V CODEN OKB Karman 117C, which makes the ship capable of reaching 489 lightyears per day during hyperspace travels.
=== Other systems ===
The Mk 41 long-range fire director is the main targeting system fitted on the Marathons. It is the same targeting system installed aboard Valiant-class and it is capable of track down multiple targets contemporary and it is so precisely at any range.
Mk 17 computer system is the main navigation system when an IA is not available. Mk 17 was the standard navigation system at the time and it remain the standard NAVSYM until the introduction of the more advanced Mk 26 in 2531. While for sublight travels Mk 17 is good enough, it isn't accurate for slipspace travels, and SFTE technology cannot help, as at the time it wasn't still perfect.
=== Crew and complement ===
Standard crew aboard a Marathon is made up of 1,000 personnel, while minimum crew required is about 589 sailors and officers. During late-war and after this amount of crew was considered exagerated, but during Insurrection ships had far less automated system, so a crew of this size was on average. Marathons can also accommodate four hundred Marines and sixty ODSTs, to which it can be added fifty personnel, ranging from an admiral and his staff to ONI operatives, as well as some other high-ranking officers or UEG diplomatics.
The two hangar bays can host, in a standard configuration, 20 Pelican dropships, 6 D96-TCE Albatross dropships, 9 C709 Longsword starfighters, 24 Warthogs, 8 M808 Scorpion tanks and 40 M274 Mongoose. As space aboard Marathons is maximize the amount of ammunition and armor, this configuration is always standard, unless a ship is remodelled to be function as a light carrier; in this case, the amount of vehicles, aircrafts and soldiers hosted is larger.
=== Armament ===
Marathons are cruisers, which means that, by UNSC doctrine, they sported more missile pods than coilgun batteries. Despite being updated throughout the entire Human-Covenant war, their armament have never been changed drastically.
==== MACs ====
==== Missiles ====
==== Coilgun batteries ====
==== Nuclear warheads ====
== Roles ==
Marathons can fulfill a wide variety of roles.
During initial development Robert McLees design the class as a purely escort vessel with a strong anti-air defense system. After reviewing design, McLees didn't remove anti-air systems, so maintaining the initially predicted escort role. As such, its primary role is escort of other capital ships, thanks not only to its anti-air guns and missiles, but also to its powerful MAC guns. Vice Admiral Cole used frequently Marathons as escort for carriers together with destroyers and frigates, as his rejected both ship-to-ship combat - due to a weak armor - and fleet and command duties, where Valiants were superior; indeed Cole, as later did Danforth Whitcomb and Graselyn Tuwa, managed to make Marathons effective beyond their capacity especially against CCS battlecruisers, losing much less ships than any other flag officers.
Another role that a Marathon can perform is fleet command, thanks to its double bridge which can allow a ship's command crew to concentrate its effort in keep safe the ship without interfere with the fleet's command staff. However its flag bridge was smaller and less advanced than that fitted on Valiants, and the sensor array wasn't as large. Nonetheless, the ship can take the lead quite effective.
== Ships of the line ==
Name 	Hull Classification Symbol	Commissioned	Destroyed 	Notes 	 	
Block I 	Block I 	Block I 	Block I 	Block I 	Block I 	Block I
 	CA-42 	2513 	2533 	Lead ship of the class. 	 	
 	CA-53 	2516 	2526 	Destroyed above Biko. 	 	
 	CA-42 	2515 	2526 	Destroyed above Bliss. 	 	
 	CA-42 	2522 	2531 	Destroyed during the Harvest Campaign. 	 	
Block IIIA 	Block IIIA 	Block IIIA 	Block IIIA 	Block IIIA 	Block IIIA	Block IIIA
 	CA-42 	2544 	2552 	Tore down above Reach. 	 	
Block IV 	Block IV 	Block IV 	Block IV 	Block IV 	Block IV 	Block IV
 	CA-70 	2519 	Still in service	Flagship of the Fifth Fleet. 	 	
 	CA-33 	2515 	August 30, 2552 	Flagship of the eponymous battlegroup. Destroyed above Reach.	 	
UNSC Defiance	CA-410 	2551 	Still in service	Flagship of the eponymous battlegroup. 	 	
 	CA-399 	2550 	Still in service	Part of the Home Fleet.