K't'inga class
The K't'inga-class battlecruiser was historically and prominently the frontline battlecruiser of the Klingon Empire for the second half of the 23rd century and well into the 24th century. Through various refits and modernizations, the K't'inga continued service well past her intended design life and into the Dominion War. Although a much rarer sight in the 25th century with the wide deployment of the Vor'cha-class battlecruiser, the K't'inga can still be found throughout Klingon space and the frontier as a multi-purposed ship of war.
Exploration and Science
Although a ship bred for war and used as a battlecuiser, the K't'inga is a deceptively adept exploration platform. The original design expectation that the K't'inga would be forced onto the fringe frontier of Klingon space for months or maybe even years at a time required that the ship be equipped with a suite of sensors to handle the unknown. This served multiple purposes in being able to relay mapping data, both passive and active, back to Klingon command to be analyzed as well as using the K't'inga's advanced sensor suite in combat situations against perspective targets. Historically, because of the advanced K't'inga sensors, the ubiquitous nature of the vessel throughout its lifetime, and the data collected over the years, the Klingon Defense Force was able to passively map out large swaths of the Klingon frontier.
The K't'inga, being the workhorse battlecruiser of the Klingon Empire for almost 100 years, also served as its premier ship of exploration in any sense that the Klingon Empire was interested in such endeavors. If ever a matter of science or exploration was required, the K't'inga was the ship that was deployed for such matters during much of its lifetime. In the modern era, ships with more advanced sensor suites such as the Vor'cha-class or Negh'Var-class would primarily be deployed to any exploration assignments of importance.
Diplomacy
Engineering
Tactical
Shipboard Life
Class History
The K't'inga-class battlecruiser first came to life as a design brought forth to the Klingon High Council by Chancellor L'Rell in 2257. The original design within the K't'inga-class, the D7 spaceframe, was an amalgamation of the greatest successes of the different designs that the Great Houses employed through their individual fleets. These designs were disparate from one another, indicative of the fracturing of the Klingon people during this time period in Klingon history, but all derived from much older designs such as the Vo'n'talk-class, Devastator-class, and Raptor-class of centuries past. Chancellor L'Rell saw the new K't'inga-class as a unifier of the Klingon people and ordered its mass production throughout the Great Houses as a symbol of that Klingon unity. The first K't'inga's were deployed only a few months later in order to assist the USS Enterprise against a rogue Federation armada. After this battle, the K't'inga did finally enter mass production as the Chancellor had asked for and quickly became the flagship and backbone of many of the Great Houses, and therefore, the Klingon Defense Force as a whole.
The first major change to the K't'inga came in the mid-2260s. By that point, the K't'inga had been in service for over 5 years and the engineers of the Klingon Defense Force had several suggested refits and remodels for the ship to increase its performance. This lined up with a budding alliance with the Romulan Star Empire, in which the Romulans were incredibly interested in the K't'inga design. The Klingons, knowing that the original K't'inga design was about to undergo a significant upgrade, traded the original design to the Romulans in exchange for the Romulans relinquishing all claims to the contested planet of Khitomer, a Klingon stronghold and one of the most strategically important planets in the Empire. Shortly after, the Klingon K't'inga's were upgraded from the D7 spaceframe to the D7A spaceframe, leaving the Romulans with the older design while the Klingons moved forward.
In subsequent decades, the Klingons continued to upgrade the K't'inga spaceframe. One of the most infamous iterations of a spaceframe appeared in the 2290s when the flagship of the Klingon Chancellor Gorkon, Kronos One, was deployed under the D7E spaceframe. Kronos One was vitally important to the signing of the Khitomer Accords, the Federation-Klingon Alliance that blossomed from those accords, and the future of the Alpha and Beta Quadrants as a whole. Many years later, as a symbol of peace and friendship, the Klingon Empire gifted Kronos One to the Federation to be displayed in the Starfleet Fleet Museum over Athan Prime.
The D7E spaceframe continued as the primary deployment of the K't'inga-class until the 2340s, when the D7F spaceframe was deployed as a significant upgrade to the internal systems of the K't'inga-class. The K't'inga-class continued for another 20 years undisturbed until the development and deployment of the Vor'cha-class battlecruiser. Seen as the first significant class in the Empire in over a generation, the Vor'cha was slated to replace the K't'inga within a decade as a massive improvement in every aspect. However, as the next decade rolled around and a new enemy came into sight, the lifespan of the K't'inga was artificially inflated.
Hundreds of K't'inga's in service at the start of the Cold War with the Dominion were slated for decommissioning and scrapping to use their raw materials to build a new fleet of Vor'cha's. However, when the severity of the Changeling infiltration issue was realized by then-Chancellor Gowron, the K't'inga's were instead repurposed back to war as the Klingon Empire invaded the Cardassian Union in 2372. When full-scale war broke out between the Dominion, now fully allied with the Cardassian Union, and the Federation-Klingon-Romulan Alliance, the K't'inga's made up a huge backbone of the Klingon fleet. The designs, while older, were still a fearsome ship of war. The K't'inga took heavy losses during the war which was on par with the overall heavy losses of the Klingon Empire. However, by wars end, the K't'inga still numbered in the hundreds. With the decimation that the Klingon fleet took overall, the K't'inga again had its lifespan artificially increased to allow the Klingon Defense Force to build its own forces.
As the Klingon forces recovered, the K't'inga began to be slowly phased out by the Great Houses. By the early 25th century, the K't'inga-class continues to serve many of the Houses but is no longer the backbone of most forces and becomes an increasingly dwindling sight in Klingon space.