sea trade routes

[BigScience]

how the heck does one establish a sea trade route? the info in the game manual is useless, and the advisor can't be tortured into revealing the answer je suis frustrated.
i have contac with all the civs in the game, my ships ply the waters with impunity, but i CANNOT establish trade routes.
any help will be greatly appreciated.

 

[Ohwell]

What is your recent tech advances???? I cant help you if you dont give info. Do you have harbors????

 

[BigScience]

sorry (duh) new to posting for help.
yes i have harbors in every coastal city. i also have navigation, magellan, and all the other advances i believe i need. my ships run the gammit from galleons, privateers, frigates, to ironclads.

 

[Ohwell]

Hmm, the computer must not have harbors yet. Other than that, I don't know. See what your trade advisor says.

 

[Bugg]

There must be a road to the harbor in the A.I civ or your civ
to what ever it is that you want.
For example you have a harbor in miami, you find oil in cuba. To establish a trade route build a road to the oil in cuba and connect it to the harbor city. The resource, in this case oil, must be inside your city radius. If it is not and it is not inside any other civs border you can build a colony by placing a worker on the resource and pressing the build button. If it is in another civs radius you have to trade for it. Sometimes they are all traded away, so you have to take it. If the other civ has not yet discovered oil then you can't trade them.
Oh yeah, the capitals also have to be connected. This means oil must be connected by road to capital of cuba(Havanna), you have to have a road that touches these roads lead to you harbor. Your other harbor has to have a road to Washington.
I hope this helps.

 

[Bugg]

I'm not sure if it works for player but it works for A.I.
If you build a city and the A.I has a harbor built if you connect to their roads you should be able to trade by sea.For example if Boston was an English held town, if you connect Washington to Bopston you can trade with England

 

[Magnus]

and remember the AI civ must have Navigation to trade across ocean squares - its a tech I gift freely