Pan Pan and a direct call to the CG explaining your situation and position. Worst case is that this will make their job easier. If there is a boat or chopper out there cruising around they might just turn in your direction anyway.
Correct me if I'm wrong, but if you send out a Pan Pan that states you may be taking on water, won't the CG reply and set up a line of communication? i.e.: A call back time in XX number of minutes?
If it's summer time and your 10 NM out in LI sound there will probably be a Sea Tow boat on the way even if you don't request them. Heck, you might have Sea Tow and Tow Boat US fighting your the right to pump you out
(not flaming them, that's how they make a living).
If the engine bilge pumps and that guy swinging a bucket with a wild look in his eyes can't keep up with the water then take a deep breath and call in a mayday.