Really? Maybe the sizes differ, but oil tankers have come in to Philly for years. I'll never forget the winter of '93 when the Delaware froze over and the Navy had to send an icebreaker to free a tanker that got stranded in the middle of the river. They've been talking about re-dredging the Delaware to increase the depth of the two channels by an extra 40 feet (it might have been done by now). Just about all we have from Philly down to the DE state line are mile after mile of refineries.
What comes up the Delaware is what is referred to as 'lighters'. Smaller tankers which lighten the load from supertankers off shore, 50 miles out. They were also going to dredge the river from 42 feet to a depth of 45 feet. Ships run aground frequently in the river but you only hear of the ones which get stuck.