The UNSC Navy is the branch of the UNSCDF responsible mostly for naval operations in space, though they sometimes operate in the oceans with their terrestrial arm. Its roles include ship-to-ship combat, orbital bombardment, the deployment of atmospheric and space fighters, and the delivery of UNSC Marines, especially ODSTs, into combat.
The UNSC Navy was formed in the wake of the Interplanetary War of the 2160's during the Argyre Planitia Campaign of 2163, as a result of the UN's need to oversee and monitor Marine deployments from space. The UNSC Navy is a direct descendant of the UN Navy, and is led by the UNSC Naval Command.
The UNSC Navy is comprised of several known fleets constructed of many capital ships and single-ship craft. The UNSC Navy sustained heavy losses of materiél and personnel throughout the war against the Covenant, with many valuable assets being destroyed defending Reach, and a substantial portion of its surviving strength lost during the occupation of Earth by the Prophet of Truth.
At the onset of the Human-Covenant war in early 2525, the UNSC Navy was hopelessly outclassed both technologically and numerically by the Covenant juggernaut. The Covenant Navy was fielding (among other technologies) energy shielding and plasma weaponry that allowed them to deliver and receive more punishment than their human counterparts. Superior slipspace navigation also allowed the Covenant to travel more than four hundred times faster than human vessels, with incomparable accuracy. This discrepancy was still very evident towards the climax of the war some 27 years later, in 2552 and 53, despite humanity's strong efforts to both innovate and emulate Covenant, and to a lesser extent Forerunner, technology.
By 2558 however, the balance of power had shifted, and the UNSC Navy was outmatching the Covenant Remnant's technology, as demonstrated at Requiem. This has been paraded with the launch of the UNSC Infinity the largest, and most sophisticated ship in the Navy arsenal, which exceeds the CAS-class Assault Carrier in size, and rivalled its shielding and weaponry. The UNSC has further refitted its current fleets with reverse-engineered Covenant and Forerunner technology gathered during the war, allowing them to not only hold their own against, but to surpass the previously superior Covenant ships.
The primary offensive armament of all UNSC capital ships is the Magnetic Accelerator Cannon (MAC). These weapons are massive coil guns that are used to accelerate projectiles ranging in mass from 600 tons in the case of smaller warships, and 3,000 tons in the case of Super MAC platforms, to extremely high velocities. These projectiles are composed of Titanium-A, depleted Uranium, and/or Tungsten with a ferrous (iron) core. Super MAC platforms accelerate MAC rounds to over point four-tenths of the speed of light  or about 120,000 kilometers per second with twenty-three linear accelerator coils, while ship-based MACs have a lower velocity. Super MAC platforms can also reload a round in 5 seconds, where as the smaller capital ships will need several minutes.
The UNSC frigate Gettysburg is quoted as firing a 600-ton shell at 30 kilometers per second. Before Reach fell, UNSC Pillar of Autumn was equipped with a modified MAC that could quickly fire three lighter projectiles in succession instead of just one heavier projectile. It was originally intended to allow Pillar of Autumn a better chance of disabling a Covenant ship, which was a feature required for a mission that was later scrubbed following the Fall of Reach.
Almost all UNSC warships are equipped with Archer Missile pods for ship-to-ship engagements, which prove mostly effective against unshielded targets. A common tactic among UNSC ships is to disable the target's shields with MAC rounds and then pummel it with Archer missiles. UNSC ships in 2525 carried Fusion rockets as an offensive weapon. They seem to have been removed or replaced in later years. UNSC ships may also carry Shiva-class Nuclear Missiles. In addition, the UNSC mounts 50mm auto-cannons on its ships for defense against enemy fighters and boarding craft, controlled by shipboard AIs. However, these auto cannons can be used against Covenant capital ships if the two ships are close enough, as displayed by UNSC Savannah during Operation: UPPER CUT.
UNSC warships also carry significant Marine detachments for internal security, boarding actions, and planetary assault, and carry all the equipment and materiel needed by Marine forces. It is implied that a significant portion of the interior of UNSC warships are devoted to this purpose, as there are armories and barracks that hold these supplies.
Ships of the UNSC navy also carry a number of GA-TL1 Longsword-class Interceptor. These are armed with 110mm Rotary cannons and ASGM-10 Missiles, and sometimes a Moray space mine system or even a single Shiva-class Nuclear Missile. They can also be remotely-operated and used to carry a remotely-detonated Shiva missile, which, when detonated, effectively destroys both the Longsword and its selected target.
Despite all of this firepower, however, UNSC warships have great difficulty defeating Covenant ships even with a numerical advantage. It typically takes multiple hits from a ship-based MAC weapon to disable a Covenant ship's shields, although larger, ODP-based Super MACs can fire a round that can literally shatter Covenant capital ships. Archer missiles must be used in tremendous amounts to breach Covenant shield systems. Even with their shields down, Covenant ships have been noted to remain operational after multiple direct hits from normal MAC rounds. This advantage in firepower and shielding gives the Covenant an effective 3:1 ratio and better against UNSC ships in combat.
Far into the 26th Century, the UNSC Navy continued to use terrestrial ships to patrol the seas of its worlds. Little is known about this Naval arm, only that bases existed on Earth's Mombasa Quays and the fortress world of Reach. Other than that, it is known that the Navy possessed numerous UNSC Aircraft carriers with a full complement of F-99 Unmanned Combat Aerial Vehicles, suggesting that they were always kept on a high-level of alert.
Aside from participating in the Battle of Mombasa to some extent, the wet Navy may have also been involved with an operation in the Yucatán peninsula where the SPARTAN-II Blue Team attacked a Covenant excavation force under the Gulf of Mexico.
- Main article: UNSC Navy uniforms
|UNSC Navy Officer Ranks|
|Ensign||Lieutenant, Junior Grade||Lieutenant||Lieutenant Commander||Commander||Captain||Rear Admiral (Lower Half)||Rear Admiral (Upper Half)||Vice Admiral||Admiral||Fleet Admiral|
|For the UNSC Navy Enlisted rank structure click here|
|UNSC All Under Heaven||Unknown||Unknown|
|UNSC Epoch||Epoch-class heavy carrier||Unknown|
|UNSC Orion||Orion-class carrier||Unknown|
|UNSC Poseidon||Poseidon-class light carrier||Unknown|
|UNSC Aladdin||Sahara-class heavy prowler||Active|
|UNSC Applebee||Unknown||Unknown, presumed Active|
|UNSC Athens||Unknown||Unknown, presumed Active|
|UNSC Dusk||Unknown||Unknown, presumed Active|
|UNSC Eclipse||Eclipse-class light prowler||Unknown|
|UNSC Edge of Umbra||Unknown||Unknown, presumed Active|
|UNSC Lark||Unknown||Unknown, presumed Active|
|UNSC Last Gleaming||Unknown||Unknown, presumed Active|
|UNSC Port Stanley||Stealth Corvette||Active|
|UNSC Razor's Edge||Unknown||Unknown, presumed Active|
|UNSC Red Horse||Unknown||Unknown, presumed Active|
|UNSC Sahara||Sahara-class heavy prowler||Unknown|
|UNSC Tokyo Rules||Unknown||Unknown, presumed Active|
|UNSC Wink of an Eye||Unknown||Unknown, presumed Active|
|UNSC Winter||Winter-class light prowler||Unknown|
|UNSC Callisto||Unknown||Unknown, presumed Scrapped|
|UNSC Chalons||Unknown||Unknown, presumed Active|
|UNSC Coral Sea||Unknown||Unknown, presumed Active|
|UNSC Pony Express||Unknown||Unknown, presumed Active|
|UNSC Two for Flinching||Fast-attack Corvette||Unknown, presumed Active|
|UNSC Bum Rush||Unknown||Unknown, presumed Active|
|CMA Season of Plenty||Unknown||Unknown|
|UNSC Spirit of Fire||Modified Phoenix-class colony ship||Left to Drift|
|UNSC Skidbladnir||Phoenix-class colony ship||Scrapped|
- UNSC Agincourt - Unknown class, Destroyed
- CMA Argo - Scout ship, Destroyed
- UNSC Armstrong - Unknown class, heavily damaged
- UNSC Austerlitz - Unknown class, Destroyed
- UNSC Basra - Unknown class, Destroyed
- UNSC Belfast - Unknown class, Destroyed
- UNSC Belleisle - Auxiliary vessel, Active
- UNSC Brilliant Shores - Unknown class and fate
- UNSC Bunker Hill - Unknown class and fate
- UNSC Campo Grande - Unknown class, Destroyed
- UNSC Dunedin - Auxiliary vessel, Active
- UNSC Excellence - Unknown class, Destroyed
- UNSC Final Summit - Unknown class and fate
- UNSC Glasgow - Unknown class and fate
- UNSC Herald - Unknown class and fate
- UNSC Hermes II - Unknown class and fate
- UNSC Hilbert - Science vessel, Destroyed
- UNSC Iceni - Surveying shuttle, Active
- UNSC Infinity - Infinity-class warship, Active
- UNSC Lance Held High - Unknown class, Destroyed
- UNSC Long Time Coming - ONI Prospecting vessel, destroyed
- UNSC Lowrentz - Unknown class, Destroyed
- UNSC Majestic - Unknown class and fate
- UNSC Maelstrom - Unknown class, Destroyed
- UNSC Midway - Unknown class, Destroyed
- UNSC Onan - Cargo Freighter, Unknown
- ONI PRO-49776 - Unknown
- UNSC Point of No Return - Stealth Cruiser - Active
- UNSC Pompadour - Unknown class and fate
- UNSC Sacramento - Unknown class, Destroyed
- UNSC Silberg - Stealth ship, unknown
- UNSC Texas - Unknown class, Destroyed
- UNSC Tharsis - Unknown class, Destroyed
- UNSC Troy - Unknown class, Destroyed
- UNSC Vindication - Vindication-class light battleship, Unknown
- UNSC Walk of Shame - ONI Sloop, Unknown, presumed active
- UNSC Waterloo - Unknown class, Destroyed
- UNSC Witch Bucket - Unknown class and fate
- Beatrice - Chiroptera-class Stealth Vessel - Decommissioned, later destroyed
- Coda - Shuttle Pod, Destroyed
- Han - Diplomatic Shuttle, Unknown
- Mona Lisa - Cargo Freighter, Destroyed
|Cairo Station||Heavily damaged|
Other orbital facilitiesEdit
|Reach Station Gamma||Orbital Drydock||Destroyed|
|UNSC Cradle||Refit/Repair Facility||Destroyed|
|UNSC Hopeful||Hospital Ship||Unknown, probably active|
|ONI Medical Facility||Unknown, presumed destroyed|
|M25L Recovery Station||Unknown|
- See UNSC Naval personnel for a list of UNSC naval personnel.
- Many UNSC Navy traditions currently in use were also UN Navy traditions. Preceding the UN Navy, they were various United States Naval traditions.
- Naval personnel are sometimes referred to as "swabbies". The term "swabbie" can be a joke or a sign of disrespect.
- The UNSC Navy provides the rank structure for the SPARTANs.
- Respirator packs are worn by UNSC personnel when an atmosphere is not present, and provides an auxiliary supply of oxygen for the wearer.