This is not a container barge, but a Ro/Ro (Roll on/Roll off) barge. There may be containers on the barge, but if they are, they are already fitted on trailer chassis. There is no internal capacity to changed decks, so there must be a three level ramp at the ports of loading and discharge, unless only the bottom deck is being worked. I worked for this company for a couple of years as an engineer on the tugs, towing the trailer barges from Lake Charles, LA to San Juan, PR; with the odd trip to Port au Prince, Haiti (where we only worked the bottom deck).

Try this site
http://www.crowley.com/ocean-towing-transportation/capabilities.asp