Secondary hull

On manyFederationstarships, thesecondary hull (also known as theengineering hull, theengineering section, thestardrive section, or thebattle section) was a major component of the overallhull structure. The secondary hull was generally located behind and below theprimary hull.

The secondary hull was usually dedicated to engineering and support functions, especially in starships built after the mid-23rd century. It was the home of thewarp drive,Main Engineering, and other engineering support systems. Separating these potentially dangerous systems from the majority of the crew, located in the primary hull, allows the secondary hull to be abandoned in the event of catastrophicdamage to thewarp core or a loss ofantimatter containment.

The warpnacelles also make a direct connection to the secondary hull. Other areas typically found in the secondary hull include theshuttlebay,cargo bays,Crew quarters,corridor,transporter room andbrig. Themain deflector dish was usually located at the very front of the secondary hull, as weretorpedo launchers.

Sometime after January2155, a secondary hull was added to theEnterprise NX-01. (PIC: "The Bounty")

OnGalaxy-class starships, the secondary hull was usually referred to as the battle section because it mounted the majority of the ship's weaponry and was intended to enter combat or other dangerous situations following asaucer separation. The saucer module, containing the majority of the ship's crew (including civilians) could then retreat to safety. Both sections could operate without one another for long periods of time. Once the crisis was resolved, the two sections could reconnect. Because of this, the battle section was designed with duplicates of systems usually found only in the primary hull, including abattle bridge,captain's ready room,sickbay,crew quarters,corridor,transporter room, acomputer core, and other mission-critical facilities. (TNG: "Encounter at Farpoint", "The Arsenal of Freedom", "The Best of Both Worlds, Part II")

Thedeflector dish weapon used against theBorg by theUSSEnterprise-D in2367 required the entire forward half of the secondary hull to be evacuated due toradiation danger. (TNG: "The Best of Both Worlds")

SomeFederation starship classes that lacked a secondary hull included theNX-class,Freedom-class,Miranda-class,Akira-class, andDefiant-class.

Severalduraniumalloy fragments of theIKSToh'Kaht's secondary hull survived its destruction nearDeep Space 9 in2369. (DS9: "Dramatis Personae")

In analternate timeline,debris from the secondary hull of theUSSVoyager was found in the29th century following atemporal explosion which obliterated theSol system andEarth. (VOY: "Future's End")

Parts of the secondary hull ofUSSSyracuse were used to rebuild the USSEnterprise-D following its retrieval fromVeridian III. (PIC: "Võx")