D5 class
The D5-class battle cruiser was a type of large warship that was in service with the Klingon Imperial Fleet during the mid-22nd century.

History 
In service as early as 2147, the D5 class was fully documented, albeit classified, in the Vulcan database. ()

The D5 class often served patrol duties throughout the Klingon Empire. One vessel of this class served as the personal flagship for high ranking fleet admiral. ()

In the 2260s, Kor commanded an attack on Caleb IV from the , a D5-class cruiser.

By the 2370s, the D5 class was considered to be an old design. ()

Technical data

Physical arrangement 

Like many of its successors in the Imperial Klingon fleet, the D5 battle cruiser was a rugged warship that was composed of diffusion bonded monocrystal and distinguished by a roughly bird-like form.

The bridge was located in the forward-most position of the ship, and was connected with a series of reinforced support cables, via an elongated neck that extended into the secondary hull. Along the nape of the neck was ship's forward sensor platform and the primary weapons array.

The bulk of the ship rested in the aft section, which flared down and out, port and starboard, into a pair of angular wings which contained talon-like warp nacelles. A superstructure rested on top of the vessel, which contained the cargo loading door, aft sensor platform, and the maneuvering thrusters. Below the superstructure, on the aft-most section of the secondary hull, were the ship's impulse engines. ()

Design variant 
The D5 class, described as being "little more than a freighter", could be modified to carry eight under-slung deuterium tanks, capable of transporting over 80,000 liters. Capable of operating with a crew of twelve and a skeleton crew of four, this variant was considerably less advanced than its battle cruiser counterpart, notably in its lack of the ventral disruptor cannon common to the class. In terms of the defensive capabilities of this design, Jonathan Archer stated that he would "lay odds they're no match for ." ()

Tactical systems 
The fully armed D5 battle cruiser was considerably more advanced than Starfleet's most powerful vessel of that era, the  starship. Indeed, the maximum speed of the D5 class was warp factor six. ()

The offensive arsenal of the D5 class was rather impressive for the time, as the ship possessed a forward weapons port capable of firing both disruptors and photon torpedoes, a 360° rotating turret containing twin belly-mounted disruptor cannons, and a dorsal disruptor array. The D5 class was protected by defensive shields and dispersive armor. ()

The D5 class was superior in almost every aspect to Starfleet's NX class; however, given ideal circumstances, it was speculated by Enterprises tactical officer, Malcolm Reed, that "sustained phase cannon fire should be able to penetrate their armor, but I doubt they'd sit still long enough to give us the chance." ()

Additional systems 
Like its  counterpart of the same era, the D5 battle cruiser was outfitted with "standard multi-spectral sensors," not unlike those used on Starfleet's NX class. () However, according to Arik Soong, the D5 battle cruiser was equipped with sensors that were "far superior" to those used on an NX class. ()

A fake warp signature matching that of a D5 battle cruiser could be generated by an NX-class starship by reconfiguring the warp coil assembly. This alteration was undetectable by Klingon sensors at a range beyond 80,000 kilometers. ()

Interior design

Main bridge 

Capable of operating with a bridge crew of three, the configuration of the D5 battle cruiser's bridge shared many features found in contemporary designs. 

At the front of the bridge, against the forward bulkhead, was the ship's viewscreen. Directly behind the viewscreen, near the center of the bridge, was the captain's chair. Directly behind the captain's chair was the entryway to the bridge, with two manned consoles located on either side of the doorway. The position of the captain's chair could also be moved toward the aft of the bridge to supplement the addition of a forward console. Along the perimeter of the bridge were several stations, each designated for a specific task. ()

Commanding officer's cabin

The commanding officer's cabin provided the vessel's commanding officer with a private place to conduct ship's business. The room contained a desk and chair with a desktop monitor. ()

Ships of the class 
Named
 

Unnamed, by commander
 Korok's ship
 Krell's battle cruiser
 Magh's battle cruiser

Appendices

Appearances 
 
  (ENT Season 2)
 
  (ENT Season 4)

Background information

Model 
Though the final draft script of , had described the D5 class as "small but menacing", writer David A. Goodman very much wanted the Klingon ship in  to be a  vessel. Yet, Executive Producer Rick Berman believed an earlier model of craft was called for, as the D7-class had been depicted in the later-set original series of Star Trek. Berman therefore came up with the name "D5 class". Script references to the D7 class, in the "Judgment" teleplay, were duly changed to reference the D5 class. Peter Lauritson interpreted that to mean a different configuration of vessel was required, so he instructed Michael Okuda to have a new Klingon ship designed. Despite his idea of using the D7 class not coming to fruition, Goodman remarked about the D5 class, "It's a cool-looking ship." ("Judgment" text commentary, ENT Season 2 Blu-ray special features; "Judgment" podcast/audio commentary) Incidentally, Berman's decree was in stark contrast with an earlier situation that the  art department had needed to face, in regard to the Klingon , when the producers, against the express wishes of the art department, had insisted on ordaining a  vessel for use as Vorok's battle cruiser in the first season episode , causing a clearly noticeable continuity error.

The D5 class was designed by illustrator John Eaves, who was reverted the chore by Okuda, and was created as a CG model by Pierre Drolet at Eden FX.  Coined the "Klingon D5 Class Tanker" in production staff circles, the model made its debut in "Marauders".  Neither its class nor its designation as "tanker" were established in "Marauders" (even though the vessel's deuterium tanks themselves were, with the ship itself merely compared to a "freighter") and it appeared only in that episode as such. The model made three subsequent appearances as a battle cruiser without the tanks, the first time in "Judgment", where it received its class designation.

The D5 class design as scaled in relation to the other models created by Eden FX was 155 meters. According to an okudagram which appears in "Judgment", the length of the D5 class was said to be merely seventy-five meters.

Inconsistencies 

In writing  DS9 Season 7 episode , Ronald D. Moore stated that he intentionally included a nod to  by means of a reference to  TAS Season 1 episode .  In this reference, the elderly Kor recalls, "I commanded the first division from the Klothos – one of the old D-Five cruisers" during the Battle of Caleb IV.  While the reference to the cloaking device-equipped Klothos matched the Klothos that appears in "The Time Trap", the design itself in the animated episode appears to be a slight variant of the D7 class, rather than a ship of the D5 class retconned later for Star Trek: Enterprise, in .

Apocrypha 
In the Star Fleet Battles series of games, the D5 class is a newer, but smaller ship roughly based on the older and heavier D6- and D7-classes. It was primarily used as a light cruiser and was designed for rapid production and high combat power in a smaller class ship. The Klingon Empire was capable of building at least eighteen ships of this class per year. Considered an exceptional design in comparison to other races' ships of that class, it was noted for its maneuverability and superior weapons' arcs. Like most Klingon ship classes, many D5s were modified into a wide variety of variants during the General War.

A 23rd century version of the D5 shows up in Star Trek Online: Agents of Yesterday using the TOS aesthetic. It is visible during the Battle of Caleb IV.

External link
 

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D05 class