Fortress-class vessel

Fortress-class vessels, more commonly known as fortresses or fortress ships, were massive warships used by the Forerunner military.

Design details
Fortress-class vessels were some of the largest and most powerful vessels in the Forerunner navy. From bow to stern the ships were approximately 50 kilometers long and 10 kilometers across at the widest point. The hull is divided into three sections. The foremost section of the ship is a massive hemispherical structure 10 kilometers in diameter. The dome's hollow core serves as living space for hundreds of thousands of Forerunner Warrior-Servants. Below the dome is a mid-section composed of layered platforms supporting landing bays and weapon mounts. The aft section of the ship is a long "tail" covered in gun emplacements and other forms of energy weaponry.

Due to their behemoth structure, a single fortress ship is capable of carrying and deploying enormous amounts of harriers and weapon-ships. During battle, fortresses would first deploy thousands of swift attack craft in outward-fanning formations. They also had automated screens of weapon-ships, up to a million of which could be commanded by individual Warriors.

At the time of the Forerunner-Flood war these ships were up to 100 km in length with far more destructive capabilities. During the Battle of the Capital, a battle group of fortresses and cruisers attacked the original Halo installations under Mendicant Bias's control. Later, in one of the final battles of the war, the Falchion's interstellar defensive clench comprised twelve fortresses—only partially mobile due to space-time debt—for a fleet of 700,000 harriers.

Known vessels

 * Deep Reverence

Trivia
From the descriptions given by the novel, the design of the fortress seems to bear many similarities to the design of High Charity.

List of appearances

 * Halo: Cryptum
 * Halo: Primordium
 * Halo: Silentium