Re: C&D Canal
Having done ths trip over 100 times Xort s right on. Trick is to plan the currents not completely the same as tides. Going to Cape May best to take the current through the canal stop off at Reedy Island on the Delaware River and wait for the "express" . Thecurrent will be with you for 5.5 hours, so f you leave 1 hour before slack, you will make The Cape May canal or point in 7 hours motorsailing at average 7 SOG.
As Xort said if you leave Cape May 2 hours or so before the incoming tide you can sweep the Delaware for 6.5 hours of peak current and through the Canal to the Sassafrass in 10 hours.
We took the trip with XORT last year and left an hour before them and rode the current all the way to the Patapasco in 14 hours from Cape May.
Let me know more specifics and I can help you pan.