Treasure Fleets in Civilization VII are a pivotal gameplay mechanic introduced in the Exploration Age, focusing on economic expansion and the gathering of wealth from distant lands. Here's a detailed explanation based on the available information:
Unlocking Treasure Fleets:
•Age Requirement: Treasure Fleets become available during the Exploration Age, which follows the Antiquity Age.
•Technology Requirement: You need to research Shipbuilding to start spawning Treasure Fleets. This technology is preceded by Cartography, Heraldry, and Feudalism in the tech tree.
How to Spawn Treasure Fleets: 
•Distant Lands Settlement: Establish settlements in Distant Lands, which are essentially continents or large islands separated from your home continent by deep ocean tiles that can only be crossed post-Cartography research.
Look for Treasure Resources in these lands, which include spices, tea, sugar, cocoa, and other luxury goods from the Age of Sail. These resources are marked and will indicate in their tooltip that they generate Treasure Fleets.
•Building Requirements: In these distant settlements, construct a Fishing Quay. This building is necessary for any settlement to start spawning Treasure Fleets automatically.
•Resource Connection: Ensure that the settlement has access to at least one treasure resource. The more resources your settlement can work, the more valuable and frequent the Treasure Fleets will be.
Managing Treasure Fleets:
•Spawning: Once you have the setup, Treasure Fleets will spawn near the coastal settlement in distant lands. The game's resource menu will show how many turns until the next fleet spawns, depending on the number of treasure resources.
•Transportation: These fleets are units in themselves, which you must navigate back to any settlement within your homeland's borders.
•Unloading: When you reach your homeland, you can select the "Unload Cargo" action from the Treasure Fleet's unit menu. This action converts the fleet into gold and Treasure Fleet Points (TFP).
Benefits of Treasure Fleets:
•Gold: Each fleet unloaded grants a base amount of gold per resource, typically around 100 gold per treasure resource.
•Treasure Fleet Points: These points contribute to the Economic Legacy Path in the Exploration Age. You earn one TFP for each treasure resource the fleet was carrying when you unload it.
•Legacy Objectives: For example, unloading 10 Treasure Fleets grants Legacy Points, and at 30 points, you unlock a Golden Age for the Economic Victory path.
Strategic Considerations: 
•Island Settlement: Prioritize settling on islands rich in treasure resources for maximum fleet generation.
•Naval Protection: Since Treasure Fleets are vulnerable, ensure they have naval escorts or that the routes are safe from hostile AI.
•Speed of Return: The quicker you can bring fleets back, the more you can benefit from the gold and points before the Exploration Age ends.
Community Insights:
•Challenges: Players have noted issues like fleets getting stuck due to lack of ports or not spawning in certain conditions.
•Suggestions: There's a desire for more nuanced mechanics, like needing to unload at ports or the addition of trade winds to affect fleet movement.
Treasure Fleets in Civilization VII thus offer a dynamic way to expand economically, pushing players to explore, settle, and manage long-distance trade in a strategic manner.
