I am confused about trading. I will give a very specific example.

I am the english and have a trading post and port in wesses(which has tradeable wool)

I then have a trading post and port in Flanders which is right across the water. Flanders has tradeable wool, silk and grain.

I have a barque in the english channel which connects the 2 territories. I also have another barque in the north sea.

But I get no income to the ports and the amount I get from the trading posts has not increased with the ports and the boats.

What am I doing wrong??