The idea here is to have a capital ship that provides large indirect combat boons targeted at frigate and destroyer themed fleets. There are some implicit issues, for example the fleet cap is simply X ships, and choosing larger ships will naturally give the player more fleet power than smaller ships. Those issues aside, here I go.
The capital ship is essentially a flying mobile shipyard. The main design largely resembles a pontoon boat. Two pontoons surround a skeletal docking berth, large enough for frigates and destroyers. Dockyard machinery faces inward and additional docking arms stick out one side, showcasing an ability to handle small ships inside or attach to larger ships outside. Hangars on the other side hold worker drones. A forward facing shield represents the "umbrella" it uses to protect its dock while on the move.
Combat stats are largely non existent and it is not meant to ever enter combat. Defenses are restricted to small and medium guns, and loadouts don't get fancier than point defense. Armor is weak and speed is fast among capital ships (I.E. kinda slow). If more than a couple frigates assault the capital ship, it's in serious trouble.
The key selling points lay in its innate skills. It is essentially a mobile shipyard. Extensive docking and repair facilities provide the "almost always recoverable" trait to all frigates inside the fleet, and boost recovery rates of all other ships significantly. Smaller ships can be fully shut down inside its shielded dock, while larger ships may be serviced from the capable external dock. These facilities make deep space retrofitting easy, granting ships a -75%/-75%/-33%/-33% bonus to retrofit costs, depending on ship size. The docking repair equipment and crew also allow additional supplies per day to be distributed on fleet repairs. This allows tiny, crippled or high tech ships to be repaired extremely quickly and be put back into the fight. Repair allocation is 5 supply/day distributed across frigate/destroyer/self, and an additional 5 supply/day distributed across any ship.
Work hangars provide 1-2 bays of heavy worker drones, which can be used as combat drones in a pinch. These drones are essential to the mobile dock's frigate recovery and docking facilities and can not be trivially changed.
The same ship maintenance facilities and drones lend themselves well to salvage efforts, providing the "Salvage Gantry" capital class hull mod.
It is not a militarized ship and has the "Civilian Hull" mod. There is a massive crew requirement (trained dock crew), but it separate from skeleton crew to make the +100% crew of the militarized hull mod less punishing.
Frigate Recovery system won't work when the dock is at critical CR. The capital ship will prioritize self recovery before all else, representing the dock needing to repair itself before it can resume service.
~~~~~TLDR~~~~~
Crew: 300-500 skeleton + lots of dock workers (500-1500)
Armor: Low (fragile capital)
Defense: Frontal shield (180 arc)
Speed: Moderate (Light weight capital)
CR cost: Extremely high (30+%)
CR recovery: 6% (docking module self repair)
CR cost: 50 supplies (extreme issues from entering combat)
Weapons: Token defense, 1-2x fixed hangar bay (work drones)
Hull mods: Frigate Recovery Systems(for fleet), shielded Destroyer-class dock (5 supplies/day), simple Capital-grade dock(5 supplies/day), Salvage Gantry(capital), Civilian-Grade Hull