Automatic trading is one of the most important features of Patrician 3. It requires a lot of planning but it works wonders when set up properly, allowing for the movement of vast quantities of goods without intervention. It involves a combination of transporting goods between warehouses (using the manager to buy and sell), and using the Captain's automatic buy/sell orders to obtain goods. Generally the first is easier to set up, as it is the most flexible and has minimal delays because there is no waiting to buy goods at the correct price.
To enable automatic trading for a ship, you must first hire a captain, then click on the Auto Trade button to set a route. You can select up to 20 towns that the ship will visit, adjust the goods that will be bought as well as the prices, and assign a town where the ship can be repaired (or you can set it to entirely skip to the next city). You can drag the towns and goods up/down on the list to change the priority order. You can also save or load a previously saved route by clicking on the File button. Finally, click on the Active button, and the captain will begin his journey.
Captains can trade twice in a single day, so it can make sense to select each town twice in a row if not transferring goods to the office. On the first stop, select the goods that should be sold to town. On the second, select the ones that should be bought from town. That way the captain will empty the ship on the first stop, and then fill the free space with new merchandise.
Types of Trade Routes
There are a few different philosophies when it comes to setting up a Trade Route system.
Port to Port Route
An easy to create, but not very efficient route. A large convoy moves from town to town, buying and selling all goods where needed. An example of such a Trade Route is the Luebeck-Rostock-Stettin-Gdansk-Torun chain.
This system is used by many advanced players. It's very reliable and requires little to no management, while allowing great control over the distribution of goods.
Hub System features a single trade center in each major region of the map. Hubs store large quantities of goods, that small convoys transport to and from other cities in the region. Separate convoys transport goods between the hubs.
There are price fluctuations in all goods and over time good players realize that there is a maximum price they are willing to buy at and a minimum price they are willing to sell at on a town by town basis. However, one of the flaws of Patrician III is that the Manager can't both buy and sell goods.
The "sucker" route solves this by using a convoy with a Captain, preferably using either Cogs or Hulks, probably just one and with minimal crew. The convoy is given an automatic trading route that is actually an order just to stay in place, buy goods and dump them into the warehouse. In turn, the Manager of the trading office is responsible for selling the goods.
This route simulates the activities of the administrator, and is mostly used in early game. A ship is stationed permanently in a city, while captain takes out various goods from the trading office, sells them to town, buys other goods from town and loads everything back into the warehouse.
This route has a few advantages over using a manager, who can only work once per day, and doesn't receive bonuses from his skill while selling the goods. The disadvantage is that lower amount of goods can be sold in this manner, plus the business production will freeze for a day if the captain takes out all the necessary materials.