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 a player does not select a downtime option for their fleet, then the fleet defaults to attacking barbarian shipping. A new player who starts with a fleet always receives this random result; it is not possible to choose an action for your fleet before you attend your first event.
A fleet can be assigned to support an Imperial navy, to engage in trade with foreign ports, or to attack barbarian shipping.
A fleet may attack barbarian vessels passing through waters near the Empire or the Bay of Catazar. The fleet has an equal chance of gaining herbs, ingots or measures, money, or mana crystals as a result of this action - as if it were an appropriate resource of equivalent level. You are free to roleplay the details of this attack as you wish, as it does not have an impact on the ongoing campaign.
A fleet may trade at the open ports of any foreign nation, that is any nation that the Empire is at peace with. Each port provides different commodities for the fleet owner and production can also vary from season to season based on the the state of the relationship between the foreign country and the Empire. Any change to the standard production of a port will be clearly marked in the Downtime system.
Declarations of war and peace are in the hands of the Imperial Senate and the Throne, but foreign nations may also choose to restrict the access of Imperial shipping to their ports - or even close them altogether if they are offended by the actions of the Empire.
A fleet can be assigned to fight alongside an Imperial navy. A normal Imperial navy has an effective fighting force equivalent to 5000 soldiers who are raw recruits. When the skills and experience of a fleet are combined with a campaign navy, they improve the effective fighting force of the army by the equivalent of 100 soldiers.
Fleets lack the deep logistical support that is the backbone of an Imperial navy and without which it is impossible to operate in large numbers. As a result it is not possible for fleets to work together independently of an Imperial navy. If you wish your fleet to take part in a military campaign, it can only do so by being attached to an Imperial navy.
A fleet assigned to fight alongside an Imperial navy is paid from the Imperial Guerdon - a bursary set up by the Imperial Senate primarily to reward military units that support Imperial armies and fortifications. A fleet with only receive a share of the Guerdon if the navy they support is Imperial in nature; a character who assigns their fleet to help a foreign navy will not receive the Guerdon.
The value of the Imperial Guerdon is divided between each military unit and fleet that supports an army in proportion to their effective strength. The Senate may vote to increase or decrease the size of this fund.
A fleet can be upgraded using weirwood obtained from the Bourse. Each time a fleet is upgraded, its effectiveness is increased by 20%. This means that the fleet produces more valuable resources when it engages with foreign ports, and increases its effectiveness when supporting an Imperial navy by the equivalent of 20 soldiers.
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 2 Imperial wains of weirwood, from 2 to 3 costs 3 Imperial wains, etc.
A fleet cannot be diversified.