It's a cafe, restaurant and bar with a terrace with great views facing the Hudson.
www.boatbasincafe.com/
West 79th Street, New York, NY, United States
+1 212 496 5542
Google map: bit.ly/Jr3mlC
It's where W79 St meets the Hudson. Take a 1 train to 79 St and walk west (downhill), or take the M79 bus a block or so. Walk under the West Side Highway and keep going. You don't see it till you're there.