This article is about the DropShip class. For the individual DropShip, see Fortress (Individual Overlord-class DropShip).
Fortress TRO3057r.png
Production information
Manufacturer Semier Data Tron[1]

Tharkad Aerospace Group[2][3]

Production Year 2613[4]
Use Assault Ship
Type Spheroid
Tech Base Inner Sphere
Technical specifications
Mass 6,000 tons
Structural Integrity 13
Length 112 meters
Width 112 meters
Height 94 meters
Drive System Anacon B500
Safe Thrust 1.5 g
Max Thrust 2.5 g
Fuel (tons) 400 tons
Fuel (days) 217.4 days
Armor 46.5 tons standard
Crew 42[1]
  • 7 Officers
  • 26 Enlisted
  • 9 Gunners

(Base Crew Type Requirement)[5][6]

  • 3 Pilots
  • 5 Engineers
  • 30 Secondary Engineers

Bay Personnel: 204

Escape Pods/Life Boats 4/5
Heat Sinks 131 single
BV (1.0) 4,347[7]
BV (2.0) 4,798[citation needed]


The Fortress-class Assault DropShip is one of the few true ground assault DropShips capable of securing its own landing zone, deploying sufficient forces to hit its targets, and providing them with indirect fire support. Carrying a combined-arms battalion and sufficient logistical and C3 capabilities to support it, a Fortress also makes an excellent anchor for any defensive line, with enough firepower and armor to give most enemies pause. However, even when it was first produced in 2613 the Fortress gained a reputation for being over-engineered and prone to breakage, and as the Succession Wars dragged on its computers, fire control system, and even fusion drives were often replaced with inferior parts. Between 2974 and 3027 less than a dozen Fortress-class DropShips were produced, and with most models over a century old, the line neared extinction. In a declassified 3025 report, ComStar reported the last of the part manufacturers had closed in the early 31st century, and no known production facilities of the class, though SDT secretly produced twenty of the vessels for the Archon in the years leading up to the Fourth Succession War.[1][8]

The alliance between the Federated Suns and Lyran Commonwealth would save the Fortress, with production restarted by Semier Data Tron to support the newly-formed Federated Commonwealth during the Fourth Succession War. Despite an initial fast buildup of twenty ships in six years, production of new Fortresses postwar slowed to an average of two a year until 3047. That initial burst had exhausted the source-unknown Anacon B500 engines. The craft built post-Fourth Succession War until 3047 were built with inferior engines: Semier Data Tron used the smaller Quad RanTech 720 drive that consumed fuel at a much faster rate from their Seeker line.[9] At the same time, Tharkad Aerospace Group fitted theirs with surplus Intruder Movem-XL drives.[3] Eventually, SDT closed down its manufacturing center to retool and refurbish the facility and reopened in early 3051 with efforts begun on producing newer, upgraded Fortresses by 3058 with properly sized Piper C1-5 interplanetary drives.[1][8][10]


The Fortress is noted for its heavy armament and protection, being as heavily armored as the larger Overlord and better armed. The heavy weapons of this loadout are the two massive AC/20s, six PPCs, four LRM-20s and eight Large Lasers. These impressive weapons are backed up by five lighter AC/5s, six SRM-6s, four LRM-10s, and sixteen medium lasers. The majority of this weaponry is located around the sides of the ship, providing immediate support against any enemy units within the landing area. The capstone of this impressive loadout though is a weapon rarely seen on DropShips: the massive Long Tom Artillery Piece, mounted in the ship's nose. The Long Tom allows the Fortress to back up its battalion no matter where they are, though it can only be used when the ship is grounded. Fully loaded the Fortress carries twenty-five tons of ammo for the Long Tom, along with five tons each for its AC/5s and AC/20s, sixteen tons for the LRMs, and four tons for the SRMs.[1][8]


The Fortress carries an entire combined-arms battalion, a company each of BattleMechs, Combat Vehicles, and Infantry, within three cargo bays. The first bay carries the ship's complement of twelve 'Mechs with a single access door. The second carries twelve heavy vehicles, though it is serviced by two doors. The last bay carries three platoons of infantry, who also enter and exit through two access doors, along with the cargo.[1]

Cargo (415.5 tons), 1 door


  • Upgrade 
    Launched in 3058, this version of the Fortress replaces the normal heat sinks with fewer double heat sinks and uses the extra tonnage to greatly improve the weapons load and strengthen the internal structure of the Dropship. First, two AC/5s, four medium lasers, and two SRM-6s were stripped out, making room for upgrading the PPCs to ER PPCs and adding Artemis IV to all the remaining missile launchers. Further, the Large Lasers were upgraded to ER, ten of the remaining medium lasers were upgraded to Medium Pulse Laser, and to help round out the new weapons load, two Gauss rifles were added to give the DropShip more long-range punch. Further, the engine was slightly upgraded to a more efficient drive and the structure of the ship was also reinforced, and the cargo capacity increased to 368 tons. Interestingly, the lifeboats of the Star League version were removed and replaced with a group of 10 escape pods. BV (1.0) = 5,831,[11] BV (2.0) = 6,072

Named Vessels[edit]

(See Category:Individual Fortress-class DropShips)


  • In German products, the unit's proper name was translated to Festung.



  1. 1.0 1.1 1.2 1.3 1.4 1.5 Technical Readouts: 3057, pp. 50–51
  2. Handbook: House Steiner, p. 147: "Tharkad Aerospace Group (TAGCorp)"
  3. 3.0 3.1 Objective Raids, p. 82: "Produced TAG Components
  4. MUL online date for the Fortress
  5. BattleSpace rulebook, p. 63
  6. DropShips and JumpShips: Operations Manual, p. 41
  7. AeroTech 2 Record Sheets, p. 240
  8. 8.0 8.1 8.2 DropShips and JumpShips: ComStar Intelligence Summary, pp. 50–51
  9. Objective Raids, p. 83: "Produced Semier Data Tron Components"
  10. Technical Readouts: 3057 Revised: Fortress, pp. 48-49
  11. AeroTech 2 Record Sheets, p. 241