How is the tradepower of nations in the Sevilla-Node atm?
Maybe another Nation send a big fleet to protect trade there and you lost som % on that node.
My Tips:
- More Light Ships to protect Trade
- split them up in several fleets to protect trade along you route Afriac/SA -> Sevilla
- get one of the trading ideas, to help you out (especially to get more traders)
- aim for 40-70% power in each important node along your route (if you get higher with less ships, thats even better. but sending a vast amount of ships to heavy crowded ones, will not work, the value suffers from diminishing returns)
- and as stated above: if you are in peace time (and do not expect rebels), set your army maintenance low, that will save a ton of ducats
There is a bazillion ducats to get in the Sevilla node, so go get it =)
hopefully that will help a bit
otherwise look for a little trade tutorial in the forums, they will help out a lot too =D