There is a spot at the end of the neck where Northport Bay squeezes itself through a gap no more than eight feet across.
Locals call it the sluice. On the map it is just the cut between the sandbar and Eatons Neck — nothing marked, nothing official. But the entire volume of water behind that bar has exactly one route through, and it uses it the whole tide — driving in on the flood, draining back out on the ebb, and barely pausing in between.
Nobody organizes it. Nobody advertises it. The moon runs the schedule and the rest is word of mouth.