The Oberth was in service for almost one century. It proves to be a very strong and reliable lightweight ship during almost 100 years.
After to be deceased of service in the federation lot of ships and spare parts still were available for civil market fleet, This makes that lot of Oberth class still continues in service in civil configuration for lot of years more
A important mission for lot of civil companies was the prospecting uninhabited planets to exploit them. This mission requires a cheap, lightweight but strong and reliable ship able to carry a small exploration teams as well a powerful detection system. Lot of deceased Oberth were bought for small and big companies to do this and else duties... and it begun to appear lot of variations.
The Starwatcher was a deep refit of the Oberth Class. A big hangar in the back part was one of the more visible modifications. That way the Starwatcher has a bigger fleet of small support ships than the original Oberth.
But probably the most important modification was a huge sensor array able to x-ray a whole planet in very little time. For this porpoise was very useful the separated hull configuration because when the main sensor array was at full power it was very recommendable that all crew evacuate the secondary hull and move up to the upper one.
Other important modifications were all the propulsion system focused in the endurance and low consumption. It has very complicated and sober sub-light engines that allows it to travel almost at light speed without need to use the warp engines. This feature proves to be a big advantage in fuel consumption during long exploration planet to planet trips. (They are not a substitute in sun to sun trips where warp speed is a need. But in planet to planet trips the warp speed probe it to be more energetic demanding)
The Starwatcher has a very weak armament (one laser, and one torpedo launcher) but it has a secret weapon. When the Sensor array is at full power it can burn all the electric system of any ship that is under the ray till more than 100km.
The Starwarcher is proving to be a very successful ship in rating cost/profit.... and the fleet is seriously thinking to take back again some old Oberth (refitted in Starwatchers) for some first contact explorations missions.