if I build a town far away near an iron deposit and build a harbor in it will the iron now be conected with my empire?? I have a harbor in my capital..

Almost, and this tripped me up badly, I think the water route is impt too.

You need a clear water route to the iron through "international" or allied waters -- if the only uncovered water route to your iron is through an enemies borders at sea, you won't get the iron.

I'm pretty sure, anyway.

You need navigation to transport resources across deep ocean squares.

you also have to have astronomy before you can trade via the coastal regions (harbor to harbor). other advance are need to trade across sea and ocean tiles...