Excalibur III class

"We can send her anywhere and she can do anything. The Excalibur will carry Starfleet into the 25th century, and she'll do it with style."

-, primary designer

The starship was a class of Starfleet vessel that entered service in 2391.

Role
The Excalibur III-class was a multirole starship in the tradition of the, , and before it. In peacetime it primarily served as a cargo vessel for logistical and humanitarian support missions, or as a science vessel for survey missions.

In combat it had the role of a cruiser, operating as a light capital ship and frequently used in a screening role to escort heavier vessels such as the and  class.

The Excalibur III-class was expected to eventually supplant the aging Excelsior-class and outright ancient as the workhorses of Starfleet. In practice the design's versatility proved both strength and weakness. While it could perform competently in most roles, there was nearly always a better choice for specific missions. Its small size limited its capability for extended or complex science missions due to the lack of internal space for laboratories and equipment, and the various classes of escorts and larger cruiser designs such as the, Galaxy-class, and outperformed it in combat. On the other hand, it also responded better to mission creep and unexpected circumstances than more specialized designs, and due to its smaller size and crew complement it was much cheaper to operate than the bigger starships.

Physical arrangement
The Excalibur III-class was deliberately reminiscent of the heavy cruiser of 150 years earlier. Structurally it consisted of a circular, domed saucer connected by a slender neck to a roughly cylindrical secondary hull that contained Main Engineering. The s were long, slender, and triangular, attached to the secondary hull by thin, upward- and aft-curved s.

Propulsion systems
The improved warp core of the Excalibur III-class gave it the power to extend its shields to protect friendly ships without affecting its own operations, an improvement that would be duplicated on subsequent construction and refits throughout Starfleet.

Tactical systems
The Excalibur III-class mounted forward and aft phaser arrays and torpedo launchers. Its standard ordnance for the latter were photon torpedoes, but like all ships constructed since the USS Defiant (NX-74205) its torpedo tubes were compatible with quantum torpedoes.

Its defenses included improved deflector shield generators and a tough tritanium alloy hull that rendered the vessel surprisingly durable.