Klingon starships
The Star Trek universe has presented a number of designs for starships of the Klingon Empire. Klingon ships, in contrast to Federation starships (especially Federation ships of the 24th century), are spartan and utilitarian in nature. Klingon ships are equipped with disruptor bolts as their primary offensive weapons.
D7 class The D7 class is the first Klingon ship design seen on Star Trek and appeared throughout the original series. It set the standard for the bulbous primary hull, long central boom, and wing-like secondary hull with wingtip-mounted warp nacelles. A number of these were sold to the Romulan empire during their brief alliance in the 2260s. The D6 is suggested as an earlier, presumably less capable version of the D7. The PC game Star Fleet Command suggests that these ships (especially the earlier D6) also carried conventional missiles, but these were never seen on screen. The opening in the forward hull was always presumed to be a weapon port, but it never saw use on screen. The D designations were never used on screen until the Voyager series, when Tuvok positively identifies a Klingon ship as a D7 class.
K'tinga class An upgrade of the D7 design, this class of ship had the same basic design, but more external detail was afforded by the higher budget of the Star Trek films. These ships were shown to be armed with photon torpedoes, which were launched from the opening in the forward hull and from an additional launcher in the aft area. It first appeared in Star Trek The Motion Picture and has seen use up to the late 24th Century.
Bird of Prey First seen in Star Trek III: The Search For Spock this has become perhaps the most common Klingon ship design in the modern Trek era. Much smaller than the D7 and Ktinga class cruisers, the standard crew complement was only about 12 crew and officers. This ship class was the first Klingon design to be equipped with a cloaking device and armed with both disruptors and photon torpedoes. They were also capable of planetary landings.
During the Next Generation era, larger versions of this ship were seen giving rise to the K'vort class. The smaller version associated with Star Trek III is designated the B'rel class. Arguably, the Bird of Prey is produced in higher numbers than any other Klingon Vessel.
Vor'cha Class The largest Klingon vessel seen on Star Trek so far, it matches the Federation Galaxy class ship in size and capability. It was first seen as the command ship of Chancellor Kmpec in the Star Trek: The Next Generation episode 'Sins of the Father'. Although a massive ship for most missions, it is the battlecruiser mainstay of the Klingon fleet and has mostly phased out the aging D and Ktinga class cruisers.
Negh'Var class starships served as flagships and saw successful action during the Dominion War. They are the largest Klingon starships to date. A variant of these ships appeared in the alternate future depicted in the Next Generation episode, 'All Good Things'.
Notes The Bird of Prey was traditionally used to refer to the Romulan ships seen in the original series. Romulan ships in the Next Generation era and after were called Warbirds. More confusion is raised by reference to Klingon Warbirds in the television series Enterprise. These designations, along with the D5-D6 designations, may be Federation code terms. Also, originally the Bird of Prey was meant to be a Romulan ship that Kruge stole. However, they dropped that part from the movie and it became a Klingon Bird of Prey
In the DS9 episode 'The Dahar Master', Kor recalls that he once commanded a D5 class ship called the Klothos. Although D6 has only so far appeared in the Star Trek gaming universe, the mention of a D5 probably makes it canon by logical progresssion. Also interesting to note, the Klothos is the vessel that this same Kor commanded in the animated series episode 'Time Trap'.
During the D7s appearance in the animated series, animators incorrectly place a short tubular extension over the forward opening on the primary hull. This is due to the fact that the animators were working from s scale model kit which includes the tubular piece. It was mistakenly believed that it was meant to point outward like a cannon. It actually was meant to be situated inside the hole with only a slight lip-like portion bordering the opening. Admittedly, the model kit's instructions were misleading in their illustrations, and although never used on screen in TOS, fans did always assume it was a cannon of some sort.
Although Klingon ships were always assumed to be armed with phasers (according to various Trek technical manuals) they were rarely seen used on screen, even in the 24th century era. The photon torpedoes carried aboard Klingon ships were based on Romulan design and not Federation.