The Heavy Cruiser variant of the D7, the D7B was produced for some of the more militant of the Klingon houses. Compared to the standard D7 the ship was far more effective in combat efficiency terms, although more costly and time consuming to build. Some 280 ships were built between 2250 and 2252, when production was switched to the more capable still D10 class.

Although highly capable and successful, production of the ‘ugh (heavy) version of the D7 was limited as it was viewed as an interim counter to the Federation Heavy Cruisers program prior to the D10 entering service in large numbers.