This is one of those things that "Enterprise" has forced a big rethink on, so far as this site is concerned. Even by Star Trek standards the makers of the show have now got an incredible amount of mileage out of this model, having used one version or another of it over some 35 years of real time, or 226 years of the show's timeline!
It strains credibility, to put it mildly, that a single class of vessel could remain in service for over two and a quarter centuries, even with refits - imagine trying to retrofit a wooden sailing ship of the 1770s with surface to air missiles and turbine driven propellor engines! But we're now stuck with it.
In all fairness, the appearance of the ship on the Enterprise episode "Unexpected", which added over a century to its known service life, appears to be a result of time and budget constraints rather than apathy towards continuity on the part of Berman and/or Braga. A new Klingon battlecruiser model was apparently being made for the show, and will appear in future Enterprise episodes. Presumably this could not be ready in time for use on "Unexpected". As usual, this article will examine the evidence and try to propose a reasonably common sense explanation for it all.
The Original Series
The TOS battlecruiser design was first seen in the episode "Elaan of Troyius". The ship was even less like the standard "flying saucer" ships of the period than the Enterprise itself. It also made excellent sense as a warship, with the big engineering hull and compact forward section contrasting well with the Enterprise's big saucer section to accommodate all the science labs and comfortable crew quarters. This image shows the model used during TOS :
Note the clean surfaces and the colour scheme, which is very similar to the one used on the Enterprise. The same vessel was seen in "The Enterprise Incident" (as a Romulan ship bought from the Klingons) and "Day of the Dove". Although the ship was never called anything except a "Klingon ship" or a "Klingon battlecruiser", it has become widely known amongst fans as a "D7 class" ship. Several other episodes mentioned Klingon vessels without showing them, especially "The Trouble With Tribbles", "Errand of Mercy" and "Friday's Child".
Deep Space Nine
Although a Klingon battlecruiser was mentioned but never seen during the Original series episode "The Trouble With Tribbles", we get a second chance at this ship in the Deep Space Nine sequel to that episode, "Trials and Tribble-ations". In this episode the DS9 crew travel back in time and play a part in Kirk's mission, albeit a covert one. The makers created new models of the Enterprise, Space Station K7 and the Klingon battlecruiser for this episode. When the Klingon ship approaches, Major Kira specifically identifies it as a D7 class battlecruiser. This is what we see on screen :
Note that while the colour scheme is somewhat greener than the TOS model this ship has the same clean hull, with the exception of a feather pattern scored into the dorsal engineering hull. The fact that this pattern is actually built into the hull, rather than being painted on, could be taken to indicate that this ship is of a different class than the TOS model, except for one thing - during TOS we never saw a shot of the top of any Klingon ship! So all we need to do in order to make this and the TOS ship identical is to assume that all TOS ships had this hull detailing, and that some captains painted their ships white while others preferred green.
Alas, Voyager then mucked things up with the episode "Prophecy". In this episode Voyager encounters a Klingon ship which has been wandering the galaxy since setting off from their home space "over a century" ago. The ship is described specifically as a D7 class, a class which was retired "decades ago". This is the ship we see :
Note the glowing nacelles, clearly different from either the TOS or the "Trials and Tribble-ations" version of the ship. Yet this vessel is canonically of the same class, as stated in dialogue. We could try to explain the variation in nacelle design away by saying that nacelles only glow when the ship is at warp, but this does not match the facts - the nacelles are clearly glowing on the ship in the above image, yet it is cruising at impulse in this shot. Indeed, the "Prophecy" ship was at impulse throughout its battle with Voyager and subsequent destruction. None of the TOS versions of the battlecruiser ever showed any glow to the nacelles, either when they were orbiting a planet as in "Day of the Dove", or at warp as in "Elaan of Troyius". This can only mean that there are two variants of the D7, the one seen in TOS/DS9 and the one seen in Voyager.
As mentioned in the introduction section, in the Enterprise episode "Unexpected" we see an early Klingon battlecruiser :
This is clearly the same ship seen in Voyager - both hull and nacelle design are identical in every detail, since the same model was used in both episodes. So we are stuck with the fact that this variant of the D7 class, already established as being in service until "decades" prior to 2377, was also in service at least as early as 2151. Indeed if we assume that this vessel was a common Klingon design of the time, rather than being the first of their latest and best class, then it would probably need to be in service for at least five years or so prior to 2151. Interpreting the "decades"since these ships had been retired to ninety years - as far as it is reasonable to go - we are left with this being the original D7 class, entering service sometime prior to 2151 and remaining in service until 2287, a service life of 141 years. This doesn't really make a great deal of sense - just look at how ship designs have changed since the 1860s, or compare the Wright brother's aeroplane with the F-22 of a century later. The technology of Starship design seems to evolve much more slowly than ships or aircraft, but Picard's Enterprise is still a much different beast than Kirk's even though barely one hundred years separates them. If anything Klingon designs should evolve even faster than their Federation equivalents - technology always advances fastest during time of war, and the Klingons of the pre TNG era appear to live in a state of almost perpetual warfare.
The Motion Picture
The first Star Trek movie presented us with a new version of the battlecruiser :
This ship is significantly different from either of the two versions of the D7 that we have looked at so far, although it is similar to both. It lacks both the glowing nacelles of the Enterprise version of the ship and the clean hull surface of the TOS version. The class name or number is never stated on screen, but novels and other backstage sources have dubbed it the "K'T'Inga" class. In the TNG episode "Heart of Glory" some stock footage of one of these ships was re-used, so we know that this version of the battlecruiser entered service in 2271 and was still in service as of 2364. This service life of at least 93 years is not so farfetched as the 141 years of the initial D7 variant, but still pushes credulity compared to a real world service life of 30 - 40 years. Again, we can assume a program of refits and upgrades followed by a descent from front line combat unit to supporting roles. The fact that the ship in "Heart of Glory" was being used to recapture escaped prisoners could be taken to imply that the K'T'Ingas were no longer considered to be front line combat units by the 2360s.
Star Trek : The Undescovered Country
Another version of the battlecruiser was seen in the sixth Star Trek movie. "Kronos One" (my Klingon isn't up to the original spelling) carried Chancellor Gorkon to a peace meeting on Earth, apparently serving as a Klingon version of "Air Force One", the American President's personal 747 airliner. The ship had the same hull detailing as the TMP ship, although the colour was somewhat lighter, but different nacelles :
Although this ship has glowing nacelles similar to those of the early D7 seen in Enterprise, a close up view reveals that the detailing on the nacelles is somewhat different. This ship is therefore not another variation of the D7, but rather a variation of the K'T'Inga. Since ST VI is set in 2293 we know that these ships must have been in service from at least this date. It is a matter of speculation whether the Klingon chancellor would choose a state of the art vessel just entering service as his personal transport, or opt for an old well proven design instead. I choose to believe the former, since it allows us to keep the service life of the ship to a reasonable minimum.
Deep Space Nine
In "The Way of the Warrior", DS9 came under attack from a Klingon fleet which included many battlecruisers. We get one good close up of these ships :
Although the colour of the glowing section of the nacelles is greener than on Gorkon's ship, the detailing of the nacelle and hull is identical to the Klingon vessel. More of these ships were seen in later episodes, so apparently this variant of the K'T'Inga class remained in service from Star Trek VI - 2293 - up until at least 2375. Interestingly, some of the ships in "Way of the Warrior" are seen firing beam weapons - presumably disrupters - from their forward torpedo tubes, indicating that the torpedo system had been pulled out at some point in the last eighty or so years.
Unfortunately, Deep Space Nine also brings up a contradiction with Voyager. We have already seen that the original D7 seen in "Enterprise" was again seen in Voyager, where it was described as having been retired "decades" ago. Yet in the first part of the DS9 final episode, "What You Leave Behind", shortly before the Allied fleet arrives at Cardassia we see this shot :
The ship above and behind the Defiant is clearly an original version D7, identical to the class Voyager met in Prophecy, still in service. It's hard to tell what kind of ship the battlecruiser at the bottom right is, but it looks like the same type. There are several possible ways to explain the appearance of this ship decades after it was retired; it's possible that Tom Paris could have been mistaken about the D7's retirement, though this seems unlikely. It's possible that yet another variant of the battlecruiser, identical to the original D7, entered service after that ship retired. But the most likely explanation is that the Klingons put these ships into mothballs when they were retired, and that they were subsequently reactivated for the Dominion war.
It is certain that the earliest known version of the D7 entered service in or before 2151 and remained in service until at least 2276. This version was also in service in 2375, so it is possible that Paris was mistaken about their retirement, giving them an active service life of over 224 years. More likely is that they were retired sometime around 2276 and then brought back into service for the Dominion war.
It is certain that the vessel seen in "Trials and Tribble-ations" was also a D7. We can only speculate as to when this variant entered service - for all we know it could pre-date the Enterprise version of the ship by centuries! My preference is to keep the service life of any ship to below a century, so I presume the Enterprise version to be the first D7 class battlecruiser, with the TOS version as a variant of it.
It is also quite possible that the K'T'Inga class is a further variant of the D7, although non-canon sources indicate that this is not the case. My own preference is to accommodate the novels by calling this a new class, albeit obviously sharing a good deal of the design.
This gives us two distinct classes of Klingon battlecruiser, each with two variants :
|D7||Original||Seen in "Unexpected" (ENT). Entered service sometime before 2151, was still in service until approximately 2277. At least one ship was in existence until "Prophecy" in 2377. Identified by simple glowing lines on the nacelles and a detailed hull surface.|
|D7||Variant||Seen in "Elaan of Troyius" (TOS) and several other TOS episodes. Was known to be in service during 2367; no other dates are available. This can be assumed to be the same vessel as seen in "Trials and Tribble-ations" (DS9), since detailing on the latter ship's hull is in an area never seen in the former ship. Identified by clean hull and no glow on the nacelles.|
|K'T'Inga||Original||Seen in TMP, this vessel was introduced by 2171 at the latest. They were in service at least until 2364, although they may not have been considered front line combat units by then. They can be identified by a detailed hull surface, lacking the 'feather' pattern of the TOS D7 class, and no glow on the nacelles.|
|K'T'Inga||Variant||Seen in "Star Trek VI : The Undiscovered Country", "The Way of the Warrior" (DS9) and other DS9 episodes, this ship is a variant of the standard K'T'Inga. In service by 2293, they continued to be operational until at least 2375. As of the DS9 era the forward torpedo launcher on these ships has been replaced with a beam weapon. They can be identified by a detailed hull and glowing nacelles. On close inspection this glowing area is of a complex shape.|
Separated in time... but only by 74 years.
Better... HMS Victory, and the USS Barry.
That's more like it!
Spot the difference...
|Yellow text = Canon source||Green text = Backstage source||Cyan text = Novel||White text = DITL speculation|
|Copyright Graham Kennedy||Page views : 18,612||Last updated : 1 Jan 1970|