Look up the currents (currents, not tides) at Tidal Current Tables
. Running with the current
makes a huge difference in time (hours). Look for the current
at the western end and hit the entrance of the canal an hour or so before peak favorable current. That will put you in favorable current all the way down the Delaware Bay.
If you can't clear the bridge in the Cape May canal you will probably have draft
issues as well - there is a lot of shoaling in there. I skip Cape May completely and stop at Cape Henlopen behind the inner breakwater (if I need to stop at all).