As to the person who basically said to toss the problem of paying for a fleet
by the government printing more money to use to pay for it -- SAY WHAT????
By the time you've paid for that grand fleet, you will have devalued the
credit so badly and caused such economic ruin that you'll wish you HAD been
invaded. Something like this is A Very Bad Idea.
Regarding starship sizes, the campaigns I have run all deal with a universe
about 500 years after the fall of the Third Imperium. Every planet that had
had a class A or B starport, that was TL9+, or had valuable resources, was
pretty well ruined with (nuclear) bombardment, literally blowing them back
into the stone age. With these worlds losing 90% of the population, and
the industry destroyed, they were effectively out for the count. And the other
worlds didn't have the technological base to build starships. Yes, when I had
I war, I had a WAR. None of this namby-pamby raiding -- total warfare, not
just amongst factions in the Imperium, but involving all the other races.
To the point: there is no capability to build 20,000 ton merchants. The largest
military ship (of which two of its class exist) is just over 5500 tons. Bulk
freighters range from 500-1000 tons. The old 400 ton patrol cruiser is once
again important. The 400 ton corsair now isn't worried about being put in the
trophy bay of a 30,000 ton light freighter. A large number of small ships works
better than a few large. It also means that 200 ton traders aren't shuttles for
50,000 ton vessels. The 'bigger is better' attitude GDW got when going from
basic Traveller to Book 5: High Guard to MegaTraveller is a bad one.