OK, we think we finally have this correct:
Playland Park in Rye provides access to Long Island Sound and beginning Saturday, May 9, car-top carried boats may be launched through September. For Rye residents, there is another year-round trick, so read on…
There is a kayak and non-motor water craft launch on the beach by the overflow parking area adjacent to Edith Read, at the rear end of the Rye Playland parking lot (this puts you right into the Long Island Sound). Parking fees apply during the amusement park operating season: $5 weekdays, $7 weekends, $10 on holidays.
When you pay the parking fee you need to tell the attendant you are going into Edith Read and you will be given a one-time use pass to open the gate at the back of the Playland parking lot. Westchester Park Passes do not allow free parking and will not open the triangle gate.
If you join Edith Read (join here – family membership $50 per year) you get a pass to go through the main parking booths without paying, and the pass will open up the triangle gate to get to Edith Read (and then you can put your boat in the water). So… if you are a Rye resident and use want use the water access several times or otherwise find a backdoor way to park at Rye Playland (not the intended purpose by the way, but hard to see how anyone will stop you), your best bet is to join Friends of Read Wildlife Sanctuary.