D-4 Class

The D4 cruiser, introduced in 2207, was an important step towards regain the technical lead that the Klingons had held over the Romulans and Federation in the mid 2150s. This was the first Klingon cruiser designed from the keel up to use a matter/antimatter (M/AM) reactor, previous designs had been modifications of existing vessels.  Unfortunately, the D4 was an overly ambitious design that ultimately failed, due to problems with unreliable weaponry, unwieldy size, and immature power systems.