are you running these ships yourself, or are civ industry producing them?
They are government run freighters, they're too expensive for any of my civilian lines yet. I wasn't sure from the OP whether you meant civilian run or civilian classed, so I guessed. The largest one in civilian ownership thus far is:
Dervish class Freighter 242,650 tons 1186 Crew 2626.5 BP TCS 4853 TH 6000 EM 0
1236 km/s Armour 1-346 Shields 0-0 Sensors 1/1/0/0 Damage Control Rating 15 PPV 0
MSP 101 Max Repair 50 MSP
Cargo 200000 Cargo Handling Multiplier 50
Magneto-plasma Drive E5 C (30) Power 200 Fuel Use 5% Signature 200 Armour 0 Exp 1%
Fuel Capacity 100,000 Litres Range 14.8 billion km (138 days at full power)
This design is classed as a Commercial Vessel for maintenance purposes
However, I believe they
would have a larger class, but they had just purchased the Dervish when the new class was designed, which left them fairly low on money (the other company at that point was giving out more in dividends than it was making, so wasn't really in a situation to do anything) and by the time they had more money the larger design had been obsoleted (and I subsequently decided to offer smaller, cheaper, fast
er vessels for civilian lines, which they've so far been building instead). Although the military is sticking to running the larger freighters and my civilians haven't bought anything for a while despite having the funds, so they may end up with enough money to purchase one of those designs.