As you already know, pirates can't conquor planets. Teching up until you can beat them is a valid strategy.
Alternatively, you could try to clear out a sector of pirates so you make fleets. Its hard to makes fleets when pirates are hunting down any ships you make. Once you have a clear sector, you can then start building up your military there by forming fleets, and use the strength of the fleets to clear more of your sectors.
maybe only the dread lords can put up some kinda resitsnace to the pirates, maybe.
The Dread Lords, and the pirates can fight each other, or atleast they did in this one game I played in the early DA betas. You may wish to tech up before the Dread Lords clear a path to you...
If i am right in thinking so, this could remain this way forever since pirates dont conqeur worlds to end my game.
No it wouldn't. The other civs will eventually tech up to the point where they can destroy those pirate ships.
i was considering reseaching massive ships and beef them up with lots of defence. but this will take time and money which i will be running out of shortly since the pirates are ripping out my trade ships..
First, spend your money developing your planets with markets and stuff. It will increase your income so you could maintian your development. Replace factories and labs if you need to.
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Now go and beat up those darn pirates.