Canon Facts Backstage Info  Speculation

Notes : The D-7 class battle cruiser was the backbone of the Klingon fleet for over sixty years. First entering service in 2245, the D-7 was a far more powerful and advanced vessel than its predecessor. Although the Federation Miranda class was at least the equal of the D-7, and the Constitution class somewhat superior, the D-7 was built in larger numbers than both of these classes combined.

In layout the D-7 set the standard for all Klingon designs up until the present day. The Federation tended to place most or all of the weapons on the primary hull, concentrating firepower forwards, then rely on speed and manoeuvrability to bring them to bear on the target. The D-7s engines were seriously under powered compared to Federation vessels; to compensate, the Klingons put the bulk of the ships systems in a large engineering hull attached to the nacelles, and attached a small secondary hull on the end of a long 'neck' section that projected forwards. This concentrated the vessels mass towards the rear, making it easier for the engines to change the vessels attitude in space. The weapons were also more evenly distributed - one torpedo tube is located in the forward hull, the other in the engineering section facing aft. Six of the ten disrupter cannon are also in the engineering hull. This gives the D-7 a greater distribution of fire than the Constitution or Miranda class.

 Facilities were also included to support up to five hundred ground troops; barracks accommodation was located adjacent to the ships six transporter rooms and the shuttle craft bay was considerably larger than previous Klingon vessels in order to support landing craft operations. Each D-7 was expected to be able to sustain ground operations for about twenty days without outside resupply.

The D-7 has seen comparatively little combat experience. Several skirmishes occurred with the Federation, generally pitting the D-7 against the Constitution or Miranda class. The Federation design was generally the victor in these encounters, although the Miranda class USS Outrider was heavily damaged in one engagement with a D-7 class.

Today the D-7 class is largely retired, but some one hundred and twenty units of the class remain in service with the Klingon fleet. They are no longer considered as combat units; instead they have been fitted with instrumentation from the K'T'Inga and Vor'Cha class cruisers to enable them to be used in training duties.