Defiant-class
The Defiant-class starship is a small, combat-oriented starship used by the United Federation of Planets. Initially developed as a dedicated anti-borg starship the Defiant class was born out of the rash of technical developments and innovations that swept throug Starfleet when the Borg were identified as a threat by their encounter with the USS Enterprise (NCC-1701-D)in system J-25. ("Q Who")
The Defiant class was constructed and designed at the Utopia Planetia Shipyards and Captain Benjamin Sisko was part of that design team. Construction was plagued with some slow downs due in part to a perceived lack of an immenent Borg attack and Engine design problems that plagued the starship even after construction was completed. The engines were so over-powered that they threatened the very structural integrity of the ship when powered up. It took innovations in the structural integrity field of the ship to bring this flaw under control.
The Defiant class was originally designated as an escort ship but this was just on paper to hide the fact the the Defiant was a dedicated warship in apparent violation of Starfleet protocols. The Defiant's main weapons suite is a pair of pulse phaser cannons that seem to provide more fire power than a standard phaser bank suite as seen on most starships. Coupled with standard photon torpedo launchers (later able to fire quantum torpedoes) gives the ship a very powerful forward weapons arc. As Sisko stated succintly in "The Search" "She's overpowered and overgunned"
The Defiant class also has experimental ablative armor that gives the little ship an extra edge once shields are brought down as the armor provides extra protection not usually afforded to Federation starships noted in particular during the episodes "Way of the Warrior" when the Defiant must withstand concentrated attacks from a Klingon Vorcha class attack cruiser (equivalent in firepower to a Galaxy class starship) for several seconds as shields are dropped to beam aboard memebers of the Cardasian Detaapa Council and in the episode "Paradise Lost" when the Captain of the Lakota complains about the ablative armor on the USS Defiant making it difficult to disable or destroy her. It should be noted that the captain also states that this armor is a secret modification of Captain Sisko's which opens the question of whether the abalatiove armor is actually unique to the USS Defiant and not standard for the class.
The Defiant class was uniquely designed in that her warp engines were kept in close and parallel to the hull as well as the spartan crew quarters and overall interior design of the ship. Doctor Bashir complained about the bare medical bay that was inadequate to deal with serious injuries as well as lacking any sort of laboratory facilities as in other starships. No families could travel on the Defiant and her crew compliment was normally kept around 47.
The Defiant class proved time and again she was more than a match for many vessels her size or larger. During the Klingon-Cardassian war she routinely defeated Birds of Prey in combat and withstood attacks from multiple Klingon warships many times her size such as the Vorcha class attack cruiser. ("Way of the Warrior") The USS Defiant when stolen by Tom Riker also proved more than capable of defeating heavy ships such as the Keldon class destroyers secretly upgraded by the Obsidian Order of the Cardassian Union. ("Defiant")
The Defiant class also performed admirably in her first encounter with the enemy she was designed to battle - the Borg, when she was among the surviving vessels of the Starfleet task force that fought a running battle over several days from the Typhon sector to Earth against a Borg Cube. Scoring damaging hits against the far larger Borg cube she was finally disabled by a concentrated Borg counter attack attack out lasting many starships far larger. ("First Contact")
During the Dominion War the Defiant class starships were usually seen as more than a match for the Jem'Hadar fighters and only truly outgunned and outclassed by such juggernaughts as the Dominion battleships. ("Valiant") The Defiant class ships were the first Federation starship to score a kill against Dominion naval forces ("The Search") and were instrumental in almost every major engagement of the war.