They were visually very similar to the D7-class but about a third the size with a shorter neck. A Federation Constitution-class starship as of the 2260s would outgun one of the scouts by a factor of forty percent.
In 2267 the IKS Vortha, a vessel of this class, was patrolling space at the edge of Klingon space near Organia. It detected the USS Enterprise making an approach to Organia and set an intercept course. After scoring two direct hits with little effect the Enterprise raised shields and destroyed the Vortha. (TOS comic: "Against Their Nature"; TOS episode: "Errand of Mercy")
|This section is written
from the Real World
point of view.
The fact that the Vortha is not a D7 class vessel is specified in the English script of the Klingon language edition of "Against Their Nature". Visually the two classes are almost entirely indistinguishable. The Vortha was originally and unseen assailant in the episode "Errand of Mercy", in the 2007 remastered version of the episode a distant view of a D7 like vessel is shown, given the similar designs this could easily pass for the smaller class described in the comic. There is a minor inconsistency in that in the episode the ship fires a magnetic pulse at the Enterprise whilst in the comic it uses more standard disruptors.
The remastered version of "Friday's Child" replaces a previously indistinct Klingon scout with a D7 like vessel, this could also be a member of this smaller D7 like scout class.