Factories can help build both ships and other tile improvements. The wiki is a good place to start reading; there are pages for both military and social production.
After you're read some and played a bit more, you should be able to root around here for more opinions and reports from players. If you don't already do it, try adding site:forums.galciv2.com to the end of a search string--that will narrow your results to just this forum. (At least at any decent search engine.)
There's *a lot* of talk around here about production & the economy.