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D-7 Class

Size Comp


Universe : Prime Timeline
Affiliation : Klingons
Class Name : D-7 Class
Type : Cruiser (Obsolete)
Unit Run :
IKS Groth [1] - Retired
plus 348 others built in total. 63 have been lost in all. 286 have been retired from service.
Commissioned : Entry date uncertain, but about 2146. Retired as of 2285
Dimensions : Length : 228 m [2]
Beam : 160 m [3]
Height : 60 m [3]
Decks : 18
Mass : 470,000 metric tons
Crew : 440 [4]
Armament : 4 x Mark 7 disruptor cannon [5], total output 750 TeraWatts
2 x  [5] with 260 rounds
Defence Systems : Standard shield system, total capacity 54,000 TeraJoules
Heavy Monotanium Double hull plus 3 cm High density armour.
Standard level Structural Integrity Field
Warp Speeds
(TOS scale) :
Normal Cruise : 5
Maximum Cruise : 5.6
Maximum Rated : 6.6 for 10 hours.
Strength Indices :
(Galaxy class = 1,000)
Beam Firepower : 15
Torpedo Firepower : 40
Weapon Range and Accuracy : 25
Shield Strength : 20
Hull Armour : 320
Speed : 150
Combat Manoeuvrability : 5,280
Overall Strength Index : 71
Diplomatic Capability : None
Expected Hull Life : 100
Refit Cycle : Minor : 5 year
Standard : 5 years
Major : 20 years


The D-7 class battle cruiser was first encountered by Humanity when the first Starship Enterprise met one in 2151. [6] The date of service entry is unknown, but by 2151 the Klingons already had significant numbers of these ships in service so a date of no later than 2146 seems to be likely. The D7 was far more powerful and advanced than the NX class Enterprise, [6] and was available to the Klingons in far greater numbers as of the early 2150s.

In layout the D-7 set the standard for all Klingon designs up until the present day. The bulk of the ship's colume is in the large engineering hull attached to the two nacelles, with a small secondary hull mounted on the end of a long 'neck' section that projected forwards. [7] This concentrated the vessels mass towards the rear, making it easier for the engines to change the vessels attitude in space. The weapons of the original D7 comprised two torpedo tubes, one in the head facing directly forwards and one in the engineering hull facing due aft. [7] There may have been other weapons also.

Facilities were also included to support ground troops, though this is not so significant on Klingon vessels as on Human or Federation ones; since virtually all Klingon warriors are well trained and experienced in hand to hand combat, any vessel with a transporter is capable of landing significant ground troops.

A D7 class vessel was used by a group of Klingon fundamentalists to depart for the Delta Quadrant in approximately 2275. Following the dictates of a religious prophecy the ship journied for over a century before encountering the USS Voyager, whereupon it was destroyed by its crew in order to fulfil the prophecy. [8]

The urgent need for as many ships as possible during the Dominion war led to the reactivation of the small number of remaining D7 ships, and some of these vessels took part in the Allied assault into Cardassian space which eventually ended the war. [9]

Colour key

Canon source Backstage source Novel source DITL speculation


# Series Season Source Comment
1 DS9 5 Trials and Tribble-ations
2 Star Trek Deep Space Nine Technical Manual Calculated from the scale diagram on page 317.
3 Star Trek Deep Space Nine Technical Manual
4 TOS 3 Day of the Dove
5 Generic canonical information
6 ENT 1 Unexpected
7 Visible on the shooting model
8 VOY 7 Prophecy
9 DS9 7 What You Leave Behind, Part 1
Series : DS9 Season 5 (Disc 2)
Episode : Trials and Tribble-ations
Book : Star Trek Deep Space Nine Technical Manual
Comment : Calculated from the scale diagram on page 317.
Book : Star Trek Deep Space Nine Technical Manual
Series : TOS Season 3 (Disc 2)
Episode : Day of the Dove
Source : Generic canonical information
Series : ENT Season 1 (Disc 2)
Episode : Unexpected
Source : Visible on the shooting model
Series : VOY Season 7 (Disc 4)
Episode : Prophecy
Series : DS9 Season 7 (Disc 7)
Episode : What You Leave Behind, Part 1


The D7 is one of the standard Klingon ships in regular service from 2151 (in Enterprise "Unexpected") right up to the 2270s and beyond (in Voyager "Prophecy"). For details of this and other Klingon battlecruiser variants, see my article on the Klingon Battlecruiser.
© Graham & Ian Kennedy Page views : 78,481 Last updated : 22 Dec 2021