Kuri's battle cruiser

Kuri's battle cruiser was a Klingon D7 class battle cruiser in operation during the late 23rd century.

In 2269 it took part in a mouse trap tactic with the and another battle cruiser in the Delta Triangle, during an attempt to capture the USS Enterprise (NCC-1701). The Klothos was to attack the Enterprise, while the other two cruisers stood by as backup. After the Klothos disappeared, Kuri contacted the Enterprise and threatened revenge upon it after it appeared as if the Enterprise had destroyed the Klothos. 

Background
Commander Kuri called the Klothos a of his battle cruiser. This appears inconsistent with Kor's statement that the Klothos was a D5 class vessel. When these ships were seen in "The Time Trap", they appear to be a slight variants of the D7 class design. It should also be noted that the actual design of the D5 class was not introduced on-screen until the episode.

A number of explanations are possible for this apparent inconsistency. Klingons might use the word "sister ship" to include all battle cruiser types. There could have been two different vessels with the name Klothos commanded by Kor, just as James Kirk commanded two ships named Enterprise. So this Klothos might have been the D7 class successor sister ship to Kuri's battle cruiser. D5 might also be a 23rd century designation for a variant of the D7 class. So Kuri's ship could also be a D5 class ship. Or, as the senility of Kor was the key focus of the DS9 episode's plot, he might have simply been confused with the class name of these old ships. The lack of canonicity of TAS may also be to blame, as the writers would not have been beholden to it.