A Fleet is a group of ships sailing with a common purpose. NPC "Fleets" consist of ships sailing in the Open Sea from groups of 6, 8 or 12 all at Level 50 to 65 and might contain some Elite Ships. as the Player Group increases the Loot Drop Chances Increases and the Easier the Fleet will become, if in case all player level 50.
The term "Fleeting" in PotBS is used to describe forming a group in order to attack the NPC fleets that contain 8 or 12 ships in an Open Sea Fight. Fleeting is mainly used for 2 purposes, first, a fast source for doubloons and Loot which can be sold at the Junk Merchant for extra doubloons. Second, it is used to fast level up low level players. All Captains in the group gain the same amount of experience as if they had defeated the NPC ship themselves (even if they never fire a shot). The average amount of experience gained per ship sunk is about 220 to 280, depended on how many ships are grouped together.
Types of Fleets:
1) British/French/Spanish Patrolling Fleet: that type of Fleet contains 8 ships, 7 any high level frigate ships, and 1 Elite 'Alexander' Fourth Rate.
2) British/French/Spanish Maneuvering Fleet: that type of fleet contains 12 ships, this can be one of the harder NPC Fleets, since it contains random number of fourth rate like the Elite 'Morduant' Fourth Rate, Elite 'Morduant' Sleek Fourth Rate, and Elite 'Alexander' Fourth Rate, add to those the Elite 'Valiant' Third Rate, and sometimes (but not often) such fleets might contain any of the Elite Second Rated ships of the line, or First Rated Ships of the Line, plus some High Level Frigates.
3) British/French/Spanish Resupply Fleet: this type of Fleet is mainly a Huge Treasure Fleet, it consists of 3 Elite 'Couronne' Galleon, some Elite Fourth Rated Ships of the Line, and high Level Frigates, the Resupply Fleet is a bit Harder than the Maneuvering Fleet and drops more loot.
4) Brethren Lurking Fleet: is the Fleet NPC of the Pirate Nation, it Contains High Level Frigates, 1 Elite 'Treason' Pirate Flagship and few random number of Elite 'Hercules' Pirate Frigate, the Fleet has a total number of 8 ships.
5) Brethren Hunting Fleet: is the Fleet NPC of the Pirate Nation, it contains High Level Frigates, a few random number of Elite 'Treason' Pirate Flagship, and a number of Elite 'Hercules' Pirate Frigates, the Fleet has a total number of 12 ships and considered the hardest fleet to encounter in the Open Sea.