Research needed to build: None
Purpose: Transport Resources and troops via cargo ships.
Build in more then one town: Yes, so that you can move resources and troops
Soft Cap: lvl 16 Can build higher but after 16 the cost is greatly increased. However level 1 port is needed to send troops off island.
General Information regarding the Trade Port
Lets take a look around the window from the Trade Port's view(once you click on your on the Trade Port)
On the left side of the screen you will see
Here you can see how much materials will be needed to upgrade and how long it will take. Also you have the option to demolish the building as well. Clicking demolish will give you a confirmation screen showing how much resource you would recover. This option is helpful for when you want to abandon a colony and recover some of the luxury resources and wood.
Also on the left you will notice
The main bit of information here is the loading speed. This displays how fast you will load goods at the current level. (Note this applies for both resources and for troops). A higher level port means you can load resources/troops faster, but it means an attacker can loot more from you as well.
Now in the middle of the screen you will see something like the following
This shows the number of current cargo ships you have, the cost for the next cargo ships and on the far right if you have the funds to purchase.
Below that you will find
This is a list of your own towns(other then the current town/colony selected) that you can send your cargo ships to. Clicking on any of the names will bring you to the follow page.
Here you can use the slider bars to send any available resources to the town seletced.(Lower half of the image). The top half is an ambrosia feature. If you have ambrosia you can purchase extra cargo ships for a single use to send/move more resources then you currently can. You can purchase up to the current amount of cargo ships you have bought with gold. So if you normally have 62 cargo ships you can hire 62 extra cargo ships for 5 ambrosia. If you have 10 cargo ships you can purchase 10 extra cargo ships. Clicking on "Transport Goods" will finalize the deal and start the loading process.
Now back to the main Trade Port view. Near the bottom you will see
Own cargo ships--Shows any cargo ships of your own currently loading goods/troops.
Foreign ships--Shows any cargo ships of someone's currently loading goods.(This occurs when someone is buying resources you have put up for sale on the Trading Post)
Below that you will see
Incoming Traders--Shows any ships incoming to your port to buy/sell goods via your Trading Post.
Trading Ports are needed to send troops off island. No port means you can not send troops off island to attack.
Cargo Ship Costs
Load Speed/Amount lootable