Defiant Class Starship

This ship was designed by the Federation in response to the Borg threat. No working prototype was complete in time for the Battle of Wolf 359. The first ship, the USS Defiant, was completed one year after that battle. Benjamin Sisko was on the design team for the ship; that, and the threat of the Founders from the Gamma quadrant led to the first Defiant-class ship (the Defiant) to be stationed at Deep Space 9. The orignal Defiant was destroyed in a battle with the Breen; it was replaced by the San Paulo, which was recomissioned as the Defiant.

The Defiant class is built for war. It is very small, with a crew of 10 to 12; it can operate with a skeleton crew of 4. It has four photon cannons, ablative armor, quantum torpedoes, and is the fastest sublight ship constructed up to this point. Additionally, it has a cloaking device courtesey of the Romulans.

1. NX-74205 - USS Defiant: Prototype and class ship; stationed at Deep Space Nine; destroyed by the Breen in an attempt to recapture Chin'Toka system (The Changing Face of Evil). Commanded by Captain Benjamin Sisko.
2. NCC-74210 - USS Valiant: Destroyed by an unknown class of Jem Hadar vessel (Valiant). Commanded by Cadet Tim Watters after the original captain and all senior officers died.
3. NCC-75433 - USS Defiant: Originally USS San Paulo; Recommissioned as USS Defiant after the destruction the original USS Defiant (NX-74205). Commanded by Captain Benjamin Sisko, and later Commander Kira Nerys.
4. Unknown: Never seen or mentioned on the show, to the best of my knowledge.

Note: In an early episode of Deep Space Nine, it was stated that The USS Defiant was a Valiant Class Starship but since then it has been named Defiant Class numerous times.

Some information taken from the Starfleet Ship Registry Database: http://www.webzone.net/rowan/sb907/ssrd/