One marina
There is one marina on the East River at 23rd Street owned by the NYC Dept. of Marine and Aviation. Seaplanes base there and some large party boats. No transients unless the Coast Guard drags you in there in an emergency as they did us once. The reception was grudging. Your best bet in your situation is World's Fair Marina at the foot of Flushing Bay. $1 a foot a night, I believe. Easy access to the City via subway. See a ball game at Shea Stadium, five minute walk. One hour or less to Hell Gate. If we hit the currents right we can make Sandy Hook in four hours in a sailboat. It's another two hours west from City Island or Pt. Washington but worth it to get a jump on the next leg as well as the chance to get out and about quickly.