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 "aggressive-defense".
When a Derf arrived at a malfunctioning beacon's location, one of its support shuttles would use a tractor beam to tow it into the ships lower hull, where was located the main repair facilities. The damaged equipment would be placed on an assembly line and underwent robotic repairs before the shuttle brought it back to space. Most of its repair missions took place along the borders between major powers where it was at high risk of encountering hostile forces. For this reason it was armed with mid-range phasers.
Of the 545 ships built only one was captured by hostile forces, the USS Acropolis. It fell victim to a trap of Klingon origin. It as been widely believed that the reason for this act was the hopes of learning a way of altering the navigational beacons along border lines. (FASA RPG module: Federation Ship Recognition Manual)
|16 Mark I, 362 Mark III, 68 Mark VI|
|38 Mark I, 17 Mark III|
|Starfleet Training Command|
|2 Mark I, 2 Mark III|
|Captured, destoyed or missing|
|19 Mark I , 13 Mark III, 3 Mark VI|