When you design a new ship, there's the "blank" template (the little cube) and the other pre-designed ships you can choose from (Defender, Cutter, Fury, etc.). If you save as a template, that design will be added to the list of designs to choose from. If I make a Small ship and call it "Best Ship Ever," I can then start a new game, research small hulls and choose to make a new ship based on "Best Ship Ever" - no other tech needed, it will appear right along side Fury and the other small ready-made ships. However, save as template will not save the position of any equipment - shields, weapons, engines etc. So I must place the parts on and save it again - with a different name, if I want - (but NOT as template this time) before I can tell my shipyards to build it.