The D7 class was a type of battle cruiser fielded by the Klingon Empire during the mid-23rd century. (Star Trek: The Original Series)


Sometime prior to stardate 3714.28, USS Yorktown, commanded by Captain Eric von Ryan, discovered the damaged, uninhabited hull of IKV Krieger, a Klingon D7-class battlecruiser near Starbase 16. The ship was used to add to Starfleet's intelligence on the class of ships. (Star Fleet Assembly Manual 2)

Following the Klingon-Romulan Alliance in 2268, a number of D7 class vessels were given to the Romulan Star Empire, who referred to them as Stormbird-class cruisers. (TOS: "The Enterprise Incident"; FASA RPG: The Romulans: Star Fleet Intelligence Manual) As part of the trade the Romulans shared their cloaking technology with the Klingons. (Ship Recognition Manual, Volume 4: Starships of the Original Series Era)

Variant modelsEdit

For much of the 23rd century, the D7 was the standard cruiser of the Klingon Defense Force. It was considered less expensive than most other heavy cruisers or battlecruisers, it also lacked the full range of scientific capabilities and the crew living conditions were spartan by Federation or Lyran standards. In combat, the D7 was noted for its superior turn rate and for its many transporters, which made it effective for hit and run raids. (Star Fleet Battles, RIS Bouteina)

D7D Akif-classEdit

Romulans surround the Enterprise, TEI remastered

Two Romulan Stormbird-class battlecruisers and one T'liss-class heavy cruiser surround USS Enterprise in 2268.

The D7D, also referred to as the Akif-class, was an early model of the D7. This model was one of those sold to the Romulans under the Treaty of Smarba. Grand Fleet Commander Ael t'Rllaillieu considered them inferior to native Romulan designs such as the T'liss-class heavy cruiser, deriding them as "built by the lowest bidder", but conceded that they were well-armed. (TOS novel: My Enemy, My Ally)

Captain Krell commanded a D7D during a 2271 sortie into the Alpha Quadrant during which he attacked the Bajoran Militia patrol cruiser RBS Verda. (Bait and Switch: "A Changed World")

Drone variantEdit

This ship was not intended as a long–range bombardment platform like the D6D, but was an experiment to produce a more effective cruiser for general combat purposes. If the experiment had been completely successful, many or most of the D7s would have been converted to this design. The lack of the rear–arc defenses was accepted by the captains but rejected by the admirals.

D7C variantEdit

These ships represented the command version of the basic D7 design. Shields and weapons were improved. These ships never received the "B–refits". The equivalent improvements had been incorporated into the original design.

D7K variant Edit

The D7K was introduced in 2270 in response to the Federation's Constitution-class refit program. Several D7's were refitted with twenty percent thicker hull armor and shield plating was added to the dorsal hull, providing greater battle versatility. New duel SIvath Impulse Engines replaced the quad engines of the D7 Doghjey and the single center line engine of the D7 Koch. The S-2 Graf unit was replaced with the new J-1 Graf Unit, providing power for the first generation of Klingon cloaking devices. Finally, in addressing combat vulnerabilities from the aft, engineering teams added a rear photon torpedo launcher.

This variant of the D7 was the pre-production test bed of the K't'inga-class and was instrumental in the Battle of Klach D'kel Brakt. (Star Trek Online Foundry: The Battle of Klach D'kel Brakt)

This D7 variant was often confused being the K't'inga-class. (VOY: Kuvah'magh).

D7VK variantEdit

The D7VK version was a D7W where some of the weapons (namely, the missile launchers, as well as several disruptor hardpoints) were removed for the ability to operate attack fighters. It was designed as a light carrier in an attempt to match the Nimitz-class carriers fielded by the Federation.

It was considered outdated by the 25th century but at least one unit was in pirate service in 2415. (Star Trek: False Vacuum: "Black Tornado")

D7W variant Edit

The design department of Kareli Space Yards, exploring further enhancements of the venerable D7 hull, incorporated several innovative features into the D7W, making it equal to the Federation's Gettysburg-class. This was the most powerful D7 variant ever produced. It was designed as heavy command cruisers.

At least a D7W unit was still active by 2386. (RIS Bouteina: "Going, going, gone")

K7R variantEdit

Among the ships transferred by the Klingons were three D7 battlecruisers. These were converted to Romulan technology and deployed as a single squadron on the Federation border. KR-variant D6s could not be converted to the K7R.

KRC variantEdit

This was a conversion of the Klingon D7C command cruiser, three of which were purchased by the Romulans. It entered service as the KRC with Type–G torpedoes and was later refitted with the Type–S torpedoes.

It is assumed that the D7 in "Eidolon]" was either a K7R or a KRC since it was escorting a Romulan convoy.

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