It is the carrier survey ships that sent of down the rabbit hole of the Commercial Carrier with Military Repair Box inside years ago. They are my stable now, either with their own engines or without and tugged (armoured shipyard built and armourless planet built stations for sitting at colonies or deep space waypoints).
My default can hold 22k of ships, 2k are made up of 4x500t boarding pods and the other 20k for combat ships (1 k FACs, 5k frig, 10k DD or 20k CA). One follows the survey ships and can launch its ships to scoop up a damaged survey ship for repairs or even overhaul.