Sent you an e-mail. Basically don't get your hopes up using a portable scanner unless you are walking the waterfront when you want to use it. That being said, there is a fair amount of tug and ship traffic using the Delaware River 24/7. This can be seen by registered users of Shipploter software via the shared-AIS from other users. Some Shipplotter users also have their own web sites displaying their AIS copy on Google maps and other instruments. But whether it is marine (voice) traffic, Digital Selective Calling or AIS, you need a fairly high antenna and be reasonably close to the source in order to receive the traffic yourself.
Other marine channels with active traffic would be Ch-13 Bridge-to-Bridge (but this is always low-power, never hear it on a portable unless you can see it), Ch-12 and/or Ch-14 may be used by the Delaware Pilots. and a variety of channels between Ch-68 and Ch-75 have a mix of non-commercial, commercial and harbor pilot usage.