I track them using any of the free marine vessel tracking...

I track them using any of the free marine vessel tracking websites that are available and keep a spreadsheet on a weekly basis on the journey of each of the 4 ships. I can then see just how productive they are in terms of any weeks parked up at anchor. I dont know volumes on each shipment through this and don't have time to find a way of getting that if at all possible. Only been doing this for the past 9 weeks. Will have a nice little pot of info at the 6 month mark which can compare it to financial releases.

PS) I have heard of high tech investors who use live daily satellite to measure the shadows on oil tankers to determine oil production based on wight of ship in the water out of certain regions. Mad stuff!!