Star Trek homeSkip to main content

Inside the Klingon D7 Class Battle Cruiser

Learn about the cruiser that became the pinnacle of combat warships in the 23rd Century.

The Klingon D7 Class Battle Cruiser was the pinnacle of combat warships in the 23rd Century. The mainstay of the Imperial Klingon Fleet, the D7 inspired fear and capitulation throughout the quadrant. To go up against a fleet of D7 warships was to invite doom…

Cruiser Cutaway

At 228 meters long and a crew of around 430, it was not the largest ship of the time. However, this versatile vessel could take on many roles in addition to being a combat ship. It was quick and maneuverable with its S-2 Graf Unit propulsion system, similar to the Federation Starfleet’s Warp Drive. On several encounters with the U.S.S. Enterprise in the 2260’s, the D7 was used as a scout ship, able to slip in and out of the Enterprise’s sensor range with ease.

The D7 was heavily armed, featuring phasers, photon torpedos, and two nacelle mounted disruptor cannons. The cannons could fire extremely powerful disruptor bolts utilizing power directly from the ships engines. Their placement on the outer wings gave them a great range and wide field of fire. In concert with the forward photon torpedo launcher, the ship could produce a devastating frontal assault on its target.

A Conflict of Interests

The Enterprise and the Federation Fleet were about to find out how long they could survive against an armada of D7 cruisers in 2267 while in conflict over the planet Organia. The Klingon forces and their leader, Commander Kor, had landed on the planet, seizing control of an oddly docile group of people. Organia was a strategically perfect planet and the Klingons and Federation wanted it for themselves.

As both fleets gathered to what what would have been the most destructive and costly war the quadrant had ever seen, the Organians had other plans. Through their non-corporeal powers, they seized both fleets and halted the conflict. Reluctant at first, both parties eventually agreed to cease hostilities. The full test of the D7 versus the Federation Constitution-Class in all out warfare was tabled, for now… (TOS: “Errand of Mercy”)

Klingons and Romulans Conspiring Together…

Another disturbing event for the Federation happened in 2268 when it was discovered that the Klingon Empire and the Romulan Star Empire had made an alliance. A few exchanges including the Romulans adding the far superior D7 to their fleet and the Klingons receiving the Romulan cloaking technology, rendering ships invisible to eyes and sensors, increased the Federation’s anxiety.

The Federation concocted a secret plan to capture one of the Romulan cloaking devices, now installed on the Romulan D7 cruisers brandishing the glorious Romulan Bird of Prey art. The Enterprise was once again sent into danger to acquire one of these precious devices. After Kirk’s plan had succeeded, the Enterprise warped as fast as it could back to the neutral zone as the Romulans gave chase. Just entering weapons range of the powerful disruptor cannons, the Enterprise suddenly disappeared. Chief Engineering Officer Montgomery Scott had been able to integrate the cloaking device into their systems and activate it just in time. The Romulan ship could have dealt significant damage to the Enterprise on the first volley of weapons, but they were too late. (TOS: “The Enterprise Incident”)

Klingons and Starfleet Working Together

If the cloaking device could be integrated into the Enterprise’s systems, then perhaps these two great ships were not as dissimilar as one might think. In 2269, the Enterprise and the I.K.S. Klothos, under the command of Kor, were able to combine their dwindling power systems in order to escape a pocket of null space in which they were trapped. The ships docked together to reach the speed of Warp 8 needed to break free of the null space pocket. (TAS: “The Time Trap”)


Kor was not the only captain of one of these mighty ships. Two other Dahar Masters (the title of a legendary Klingon warrior) would also command the D7, Kang and Koloth.

Captain Koloth would encounter the Enterprise several times in the 2260’s. Two of note involved Sherman’s Planet, a world the Federation was attempting to develop. Koloth would meet Kirk at Deep Space Station K-7 with the I.K.S. Gr’oth. Koloth and a Klingon spy, Arne Darvin attempted to poison the grain bound for Sherman’s Planet, but were thwarted by one of the most hated, reviled, loathed villains of the Klingon Empire, Tribbles. (TOS: “The Trouble With Tribbles”)

Tribbles would again play a role in foiling the plans of Captain Koloth. In 2269, the empire had developed a new starship projected stasis weapon which could render opposing ships completely inert. Koloth, now in command of the I.K.S. Devisor, proceeded to test the weapon against the Enterprise whilst it was distracted escorting two robot grain ships and after giving chase to the privateer, Cyrano Jones. Jones had previously been the cause and solution to the previous problems on K-7. The projected stasis weapon was a great idea in theory, but in practice, it also immobilized the ship projecting the beam. All the power required to use it drained the ship itself. (TAS: “More Tribbles, More Troubles”)


The D7 would eventually be refit into the venerable K’Tinga Class. The K’Tinga would continue on well into the next century, even taking part in the Dominion War. The legacy of the D7 would inspire many Klingon ship designs in the years to come, most all featuring a long neck with the command center at the end, wings with disruptor cannons, and a generally sleek, aggressive look.

Behind the Scenes

The D7 was designed by art director Matt Jefferies, designer of the original U.S.S. Enterprise. He “had to design a ship that would be instantly recognizable as an enemy ship, especially for a flash cut. There had to be no way it could be mistaken for our guys. It had to look threatening, even vicious.” The studio filming miniature was built by AMT, who would later produce a model kit.” (Matt Jefferies, Star Trek Sketchbook, 1997)

Ian Kisluk is an avid Star Trek fan and collector. Trek model and prop building as well as stage acting are his most prolific passions. Follow him @Starchwreck on Twitter and check out Starchwreck Props and Models on Facebook.