My fleets range in size from 300 to 500 ships. I usually have 5 fleets, each having 100 ships.
05 Escorts.
15 Destroyers
15 Light Cruisers
20 Cruisers
15 Battle Cruisers
10 Battleships
05 Dreadnoughts
05 Heavy Carriers
04 Large Troop Transports
01 BaseShip
05 Supply/Repair ships.
I also have Tatical fleets and Search and Destory Fleets. Those usually only have about 25 to 30 ships, and are all BC, BS, Carriers.
Then I have my Planetary Defense Fleets. Those consist of fighters, WP, and Sat. Sometimes 50 or 100 escorts or destoryers depending upon the threat. Usually by the time I can aford to produce 500 + ships and maintain them, I seldom need Planetary Defense ships, and either scrap em, merge em with a fleet, or trade them off to the AI. I even mothball some just for ****s and gigles.
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"We've made too many compromises already, too many retreats! They invade our space and we fall back -- they assimilate entire worlds and we fall back! Not again! The line must be drawn here -- this far, no further! And I will make them pay for what they've done!" -- Captain Picard STNG
New Age Ship Yards