#d7 class

Star Trek: The Original Series - Klingon D7 Battlecruiser by John Carlance

Klingon D-7

Unnamed D7 cruisers pictured in Federation space circa 2254. While precise dates cannot be nailed down it is likely the D7 began its development late in the four years war as a replacement for the D5 and D6 cruisers which then made up the bulk of Imperial task forces. Likewise it cannot be known for certain when the first D7 entered service, though 2250 is an often cited date. What is known for sure about the vessel however is that it first became known to starfleet in the Xian incident of 2254 when a pair of the new class, pictured above, penetrated Federation space along the border and made several sensor sweeps of the Xian system before they were met and escorted out of the system by USS Holmes NCC-1227. The captains of the two new Klingon ships apologizing and claiming sensor malfunctions, though it was obvious the move was a deliberate probe of Starfleets defenses. The existence of this new and powerful class sent shockwaves through starfleet and led to immediate efforts to upgun the then building Constitution class heavy cruisers as a precautionary measure. However it was soon judged the new ships would be more than capable of matching the D7 in any likely combat scenario. An enduring symbol of the UFP-Klingon cold war of the late 23rd century the D7 remained in production until 2274 at the latest, seeing over one hundred vessels built and remaining in service well into the 2290s before it was gradually phased out.

Star Trek: Strange New Worlds - Klingon D-7 Battlecruiser

Rivers of Blood by Jetfreak-7

My Own Mirror by thefirstfleet

The original predator by thefirstfleet