The Intrepid-class starship was a Federation design that entered service in 2371 (2012 in my fanfics). The Intrepid-class was designed for long-range exploration missions. At less than half the size of a Galaxy-class starship, it was considered "quick and smart."
The ship is equipped with the new class-9 warp drive which allows it to reach warp 9.975, new circuitry augmented with bio-neural gel packs which respond faster than standard circuitry, has variable geometry pylons to which the nacelles are attached to, allowing the ship to raise them when going to warp to reduce damage to subspace. It also includes the Emergency Medical Hologram (EMH).
The ship is extremely maneuverable for a cruiser its size (in size it is in good company of the Akira and Nebula classes). It is often regarded as a long-range exploration cruiser or light cruiser, but there were several other classifications listed such as: battleship, destroyer, frigate, science vessel, surveyor and scout.
The ship is equipped with four phaser arrays, all located on the primary hull. The larger or main ones (which outstretch from fore to the middle of the primary hull) located dorsal and ventral, use type X phasers. The class had five torpedo launchers: two fore (above the main deflector), two aft (below the aft sensor array) and one ventral (in front of the ventral phaser array on the stardrive section).
The ship mostly carried class-6 and class-9 photons. It also carried four class-10 photon torpedoes and tricobalt devices, which are not standard issue on Starfleet vessels during that time. Later, during the 2380s, quantum torpedoes would become standard issue on Intrepid-class vessels.
The USS Voyager was the only known vessel to carry transphasic torpedoes and ablative armor generators, and later, a cloaking device.
The USS Voyager is the most famous ship of the class, as it has completed an unscheduled seven-year journey in the Delta Quadrant.
There are several more versions of Voyager in different fanfics.