When the amount of wealth transported by sea becomes too great and too tempting for pirates and the like, the best strategy is to combine the different merchant ships into single, well-protected treasure fleets. Similar to the land-based wagon trains, these fleets consist of many cargo ships which transport not only goods and gold, but also the provisions needed for long trips, and the mariners needed to defend them against those with evil intentions. These treasure fleets are then much more effective at long-distance trading than single cargo ships that are usually deployed by non-seafaring nations.
- +4 Gold from all your sea trade routes.
This level 3 Policy is not that exciting - the potential Gold boost from Merchant Navy is greater, even without considering its other effect. Still, it provides a direct increase in your wealth. After adopting it, you should focus on establishing sea-based trade routes to make the most of the Policy's benefits.
Take this Policy as the fourth in the tree, unless you intend to enter sea battles soon. In this case, you should take Navigation School for the free Great Admiral, and take Treasure Fleets last to finish the tree.
At various times, nations transporting large amounts of treasure and trade goods have resorted to convoys of transports to improve the chances that the cargo would actually arrive at its destination. The most famous was the annual Spanish treasure fleet that brought gold, silver, spices, tobacco, pearls and other riches from the West Indies to Spanish ports in Europe from 1566 to 1790 AD. The sack of Spanish Havana by French privateers and attacks on lone galleons by English buccaneers moved the Spanish to institute the convoys between the New World and Europe. Although the seas are relatively safe from pirates now, during wartime maritime nations still organize convoys to improve the chances of merchant ships arriving intact.