The Derf-class was a type of Federation starship in service in the 23rd century, it was used for more than twenty-five years. Produced by the Merak shipyard at a rate of four per year. It has been classified in mission roles as a class IX tender. It marked a new concept in navigational beacon repair. The Derf-class eliminated the need for beacons and buoys to be brought in to space stations for repairs. Thought it was not designed for offensive missions, it was capable of "agressive-defense".