Great Britain - game allows too many trade routes?

[Servius]

It's also a risk though sometimes, because for the AI nations, it seems to direct ALL trade to a particular port. If that trade port gets blockaded, no trade for you, even if you have other trade ports that the trade could go to.

For example, even if Russia holds St. Petersburg, all of Russia's trade goes through Sevastopol, which means through the Med, which is full of pirates and naval states...

[Fisherking]

It's also a risk though sometimes, because for the AI nations, it seems to direct ALL trade to a particular port. If that trade port gets blockaded, no trade for you, even if you have other trade ports that the trade could go to.

For example, even if Russia holds St. Petersburg, all of Russia's trade goes through Sevastopol, which means through the Med, which is full of pirates and naval states...

It is changed from the 1.1 & 1.2 system. Overland trade is unaffected. Some overseas trade is redirected and some going to other ports is also unaffected. Port size also makes a difference of where the trade goes.

In my last campaign in 1.4 I noticed ports switching on and they suddenly had trade routes going to them. Some I still can’t explain. I was Austria but I had trade going into Portugal and Spain which were not contiguous with the rest of my lands. I did have land routes with the countries in between but that has never happened before.

[Kantalla]

The trade system changed 1.3-1.4 from what I could see.

What I believe happens now is that when a trade agreement is formed, the closest two trading ports that are either part of the relevant Capital regions, or with a direct land route to the Capital regions are linked together, provided they have spare capacity.

In some circumstances, it is possible for goods to have two sea stages with a land stage in between. For example, if you start a game as the Ottoman Empire, your trade route with the Mughal Empire comes in to Basra in Mesopotamia, then goes overland to Anatolia, before crossing the Aegean Sea to Thessaloniki in Rumelia. Likewise your cotton from Egypt and Syria is exported from Syria to Rumelia rather than take the land route. I presume this is how Fisherking was seeing that trade from Portugal when playing as Austria.

Two trade ports in a single province can do odd things sometimes too. Playing as Spain I had a second port appear in Hispaniola, and when that happened, all my American trade came into the western of the two ports and went out the eastern port. That suddenly meant my entire trade income from the Americas could be cut off by a single pirate sloop blockading either port!