Just prior to the explosion on Praxis in 2293, Starfleet had finished construction on it's latest class of shuttlecarrier, the Ark Royal
. Six months and one treaty later, Starfleet had a proverbial "white elephant" on it's hands. Not allowed to keep the ships in commission due to the stipulations of the Accord, Starfleet nevertheless did not want to simply send them to the breakers or stick them in a Boneyard to slowly rot.
What then, were they to do?
It was finally suggested that they be converted into exploration vessels. With 70%+ of the space allocated to small craft and their support systems reconfigured into labs, crew facilities, and storage space, the ships would still have more embarked craft than any cruiser or frigate, and science facilities comparable only to those found on certain starbases.
The robust hull construction inherent to shuttlecarrier designs would allow the weapons and shields to be downgraded, keeping the ship safely within the limits imposed by the Accord, and if anyone noticed that those last changes could be quickly and easily undone with minimal dockyard time (which would turn the ships into a highly effective super-heavy cruiser/battlecruiser, they didn't bother to bring the subject up.
The 12 ships of the "new" class, rechristened the Khitomer
class all went on to have highly distinguished careers in the Galaxy Exploration Division, and are considered by many engineers to be one of the best examples of starship re-purposing ever completed, and certainly one of the most robust designs of the early 24th century.