Dreadnought class

The Dreadnought-Class was an experimental starship class that was developed by the United Federation of Planets back in the 23rd century.

Developement
The Dreadnought-Class vessel was designed to be a very powerful battlecruiser; with heavily advanced and experimental weaponry. The ship was designed to be manned by 1 or more people and was capable of multiple warp capabilities; including the ability to engage vessels that were unable to fight back at warp. The vessel is extremely large and is 3x the size of the Constitution-Class vessel.

USS Vengeance
Admiral Alexander Marcus was helped by Khan Noonien Singh into creating advanced weaponry that could work against enemies of the Federation. One of these weapons was the Dreadnought-Class vessel. The first Dreadnought to ever be built was the USS Vengeance.

Admiral Marcus utilized the Vengeance to go after the USS Enterprise under the command of Captain James T. Kirk. Kirk's orders were to end the life of Sargeant John Harrison; who was responsible for the deaths of multiple starfleet personnel. Upon discovering that Kirk was in violation of his orders; Marcus attacked the Enterprise while she was at warp; compromising the ship's primary systems.

Once near Earth's Moon; the ship continued to attack however Montgomery Scott sabotaged the Vengeance's weapons; long enough for Kirk and Khan to board the ship. Once boarded; they took out the crew; however Khan double crossed Kirk and Scott, then held them hostage in hopes of getting back his crew.

Commander Spock delivered his people and recieved Kirk, Scott and Carole all back; but Khan openned fire on the Enterprise; compromising even more systems and causing the ship to almost crash into Earth. While on the Vengeance; Spock detonated the torpedoes that Khan's crew were in; what Khan didn't know was the the torpedoes he recieved were not actually containing his people; in fact they were aboard the Enterprise.

The Vengeance crash landed in San Francisco and took out a significant portion of the city, including the famous Alcatraz prison. Khan managed to escape and was later on the run from Commander Spock due to the fact that Kirk died while saving the Enterprise from certain death.

Salvage
After Khan destroyed the Vengeance; Starfleet managed to get specs from the Dreadnought and developed the same vessel; however left it disarmed for their plan to later have weapons modified onto it in the 24th century.

USS Leviathon
By the 24th century; Starfleet discovered that another vessel was made and yet unarmed. They modified the ship to be extremely combative whenever it needed to be and upgraded the technology aboard. USS Enterprise's former Hazard Team officer Daniel Rogers was put in command of the now named USS Leviathon. Rogers was also accompanied by his wife Sarah Murphy who was promoted to commander and although she was not supposed to serve aboard the same vessel as her husband; special accommodations were put in place by Captain Jean-Luc Picard.