The smallest component of the fleet organization, a Line Element is simply an individual command (ship). The rank of a Line Element’s commanding officer varies based on the mass and ORBAT classification of the ship. A small Attack or Guard Ship might be captained by as low as a Lieutenant Commander whereas a Battleship would be captained by a full Captain. Regardless of actual rank, the commander of a ship is addressed as “Captain”.
A Line of Battle within the Republic Navy is the most basic unit. Its organization is composed of as few as 4 to several dozen ships, depending on the type of line and its purpose. By nature, Lines of Battle can be easily changed, adding and subtracting Line Elements from within a Squadron. A Line of Battle is commanded by a Captain of the Line, who is the most senior commanding officer within the Line. The seven codified Lines within the Republic Navies ORBAT are: Assault, Heavy Assault, Battle, Skirmish, Troop, and Bombard.
Likely the most common Line type within the Republic Navy, a Assault Line is intended to directly engage enemies in combat and consists of between 3 and up to a dozen Attack Ships (or more, depending on vessel mass), frequently accompanied by 1-3 Guard Ships. An alternate configuration consists of solely Guard Ships, numbering between 5 and 10 such ships.
Heavy Assault lines are intended for operations where greater firepower and durability is needed than a Assault Line provides. They generally consist of between one and three Patrol Ships escorted by 3-5 Attack or Guard Ships.
Bringing immense destructive power to a battlefield, a Battle Line is comprised of a single Battleship. Battle Lines are quite rare within the Navy.
Skirmish Lines consist of smaller ships and craft, such as system patrol vessels, fighters, and assault shuttles. The make-up of a Skirmish Line varies widely based on the vessels and craft making it up. Lines made of primarily Strike Craft usually consist of a full Wing, numbering between 50 and 120 craft. It is not uncommon for larger ships (or larger groupings of small ships) to have their Auxiliary Craft organized in to a Skirmish Line paired with the parent Line.
Troop Lines are tasked with bringing Army forces to a hostile planet or installation. They usually consist of between two and four heavy Troop Transports and 4-6 Guard Ship escorts. A Troop Line can generally deliver a full Army Corps, numbering around 70,000 soldiers, including all equipment, armor, and garrison bases.
Bombard Lines bring heavy support fire to a Squadron and consist of 1-3 Field Support Ship and their escorts, usually 4-6 Guard Ships. Bombard Lines can bring enough firepower to a battlefield to slag entire worlds easily or wipe out whole fleet from range. However, due to their relative vulnerability and high target priority by enemy ships Bombard Lines rarely operate without support from other Lines.
A Squadron is composed of several lines and usually numbers between 13 and 70 ships. A Squadron is commanded by a Vice-Admiral and is the smallest force within the Navy intended to operate independently from High Command. The four codified Squadron types within the RN ORBAT are: Light, Heavy, Battle, and Troop. While not technically permanent (like Systems Force and larger) unit within the Navy, Squadrons generally operate for extended periods of time without reorganization.
A Light Squadron is intended to patrol areas with known to be free of significant enemy forces. They consist of two Assault Lines and a single Skirmish Line.
A Heavy Squadron is intended to patrol areas or engage systems with no significant enemy presence. They consist of two Heavy Assault Lines, one Assault Line, and a Skirmish line for situations where the enemy composition or position is unknown. When enemy forces are known to be defending a fixed asset the Assault line is substituted for a third Heavy Assault Line.
A Battle Squadron is distinguished from a Heavy Squadron by the addition of a Battle Line. It usually consists of the single Battle Line escorted by two Assault Lines and a Skirmish Line. The two Assault lines where occasionally replaced with two Heavy Assault or one Heavy Assault and one Assault line.
Used when a major invasion was planned, a Troop Squadron can deliver a truly staggering number of soldiers to a planet. They consist of two Troop Lines, an Assault Line, and a Skirmish Line and can transport and deploy a full Army to a planet.
A Systems Force’s operations cover multiple star systems consisting of several Squadrons under the command of an Admiral. Usually being the senior officer within the group, the commander of the Systems Force is addressed as the Commodore. A Systems Force is the smallest permanent (requiring time to reorganize to another unit) unit within the Navy. At the level of Systems Forces group structure is less defined, allowing for more organizational flexibility on the part of the Commodore. The two most common general organizations are Force Escort and Force Superiority.
Force Escort is focused primarily on maintaining security within already controlled space. They protect important economical assets (both space stations and facilities) and commercial ships as well as being tasked with hunting down and destroying pirates. A typical Force Escort Systema Force consisted of two Heavy Squadrons and two Light Squadrons.
Force Superiority focuses on operations in contested or openly hostile space, aiming more for raw firepower over flexibility. A typical Force Superiority Systema Force consists of three Heavy or Battle Squadrons supplemented by a Light Squadron.
The largest currently applicable Navy structure, a Fleet combines several System Forces under a single Admiral of the Fleet (frequently shortened to Fleet Admiral). Depending on the systems and operations it is responsible for a typical fleet consists of several hundred vessels, usually including one to two dozen Patrol Ships and a few Battleships. Fleets contain all of the support elements necessary to operate for indefinite periods without resupply, including repair ships, fleet tenders, factory ships, and agricultural ships.
Technically allowed for within the Republic Navies ORBAT, a Sector Group is the sum total of all Navy ships and operations occurring within a Sector under the command of a High Admiral. Currently there is only a single Sector under the control of the Occhestan Republic and because of this all Navy vessels (excepting those in the Reserve Fleet) fall under the same Sector Group.