IKS Heart of Qo'noS

Heart of Qo'noS was a Klingon starship in service in the 23rd century. In 2268, Heart of Qo'noS entered Federation space, supposedly due to navigational error. They were instructed to return to the Klingon Empire that, unknown to low-level commanders, brought the ship within sensor range of "The Yard", a secret Federation research facility. The Heart of Qo'noS left Federation space without incident after Spock convinced the Klingons the Yard was a salvage yard. (SS TOS (Devices and Desires))