A fleet represents one or more ships; it could be a single large swift vessel or a fleet of half a dozen much smaller vessels. Fleets are able to sail to foreign ports to trade for resources and precious items that are valuable in the Empire.
If the players does not select a downtime option for their fleet, it is randomly assigned a single foreign port to visit between events. The owner gains the resources to be had from trading at that port.
You may choose one of seven foreign ports to trade with, or one of two ports to raid. The resources that each port provides are listed below.
Nemoria (Asavean Archipelago)
3 doses of cerulean mazzarine, 3 ingots of orichalcum, 3 measures of iridescent gloaming and 2 ingots of tempest jade.
The Sarcophan Delves
3 doses of marrowort and imperial roseweald, 3 measures of beggar's lye and 3 ingots of weltsilver.
Vezak (Southern Principalities of Jarm)
3 measures of dragonbone and ambergelt and 3 mana crystals.
Kavor (Northern Principalities of Jarm)
4 doses of cerulean mazzarine, 3 ingots of green iron, 3 measures of iridescent gloaming and 1 mana crystal
Leerdam (Eastern Commonwealth)
3 doses of bladeroot, 3 ingots of tempest jade, 3 ingots of green iron and 2 measures of beggar's Lye.
Volkavaar (Western Commonwealth)
3 measures of ambergelt, 3 measures of weltsilver and 3 mana crystals.
Zemeh (The Sumaah Republic)
4 ingots of orichalcum, 4 measures of dragonbone and 3 vials of liao.
3 ingots of orichalcum, 3 measures of ambergelt, 2 drams of Bladeroot, 1 measure of dragonbone and 30 rings
Dubhtraig (Broken Shore)
3 ingots of tempest jade, 2 ingots of green iron, 54 rings, 1 imperial roseweald and 1 mana crystal
A fleet can be upgraded using weirwood obtained from the Bourse. A fleet produces more valuable resources each time it is upgraded, according to this chart of foreign ports.
To upgrade a fleet requires Imperial Wains of weirwood equal to the level the fleet is being upgraded to. So the first upgrade of a starting level 1 fleet costs costs 2 Imperial Wains of weirwood, from 2 to 3 costs 3 Imperial Wains, etc.
Instead of Trading with a Foreign port or Raiding a Barbarian port, you may choose to Raid a Foreign port or Trade with a Barbarian port. Doing either provides 1 additional effective level to the personal resource for the purposes of that action.
Raiding a Foreign port will aggravate that nation. If sufficient raiding occurs it will lead to the port being closed to the Empire, and therefore unavailable for trading. If this occurs it will still be possible to raid that port, but there will no longer be a bonus for doing so. Further raids against that port may result in them offering aid to the Empire's enemies.
Trading with a barbarian port will aid those Barbarians. It will not make them more friendly to the Empire, and indeed is illegal.