I took a glance at your city(not enough time to check every detail),One thing obvious to me is that you have way too many docks in the city,and the worst part of it is,they are scattered around the whole island!In such kind of situation a ship would probably spend a whole year visiting every dock in your city(they tend to do so,even if they have already bought 1100 and sold 1200,the maxium for each trip).No surprise that they cannot hit the quota.(they complain probably due to the ship arrived at your city in the previous year,thus not able to do any trade before the time is out,The other reason for ships doing no trade is,somehow the ship cannot find a road connecting to the "accepting" storage yard(from the dock) or the storage yard lost labour when the ship is docking)
As an advise,build only one dock closest to the entry/exit point whenever possible,buid storage yards accepting imports/exports close to the dock,let your storage yards cartpushers do the transport(using "get" command),and as I said in post#3.detach the dock area from rest of the city usually can provide the best result.If you find there is the need for more docks,add one or two very close to the existing one.The key to water route trade is optimize the docking time and let the ships doing more round trips(usually 4-5,and in ideal situation,7 ).
Read the posts I recommanded to you then rebuild the whole city!
[This message has been edited by Plebus (edited 09-02-2000).]