By either allowing players to choose or assigning players a technology path in which equipment listed on it can be enhanced beyond the normal output and possibly finding resources related to crafting at a higher rate this would encourage trading and combat both.
Make enhanced technology capturable by capturing a ship or location. This way they can't produce it themselves but either need to steal it or buy it from another player.
Make enhanced technology capturable by capturing a ship or location. This way they can't produce it themselves but either need to steal it or buy it from another player.