Hell's Gate is really no big deal at all if you time the currents right. I've done it many times with no trouble. You need to stay alert to the large commercial vessels that course through the narrow passage from Throggs Neck to the Battery. You may need a clothespin for your nose as you pass the garbage depot in the Bronx. I have spent the night on the hook, waiting for the tide to turn off College Pt., and watched the jets roar overhead into LaGuardia airport. Very cool.
I once missed the tide, yet still motored up the East River against a 4.5 kt current. With my engine at full speed, I could barely keep up with the pedestrians walking alongside the FDR Drive. Quite embarrassing!