Most of cape's ponds are kettleholes, i.e. quite deep. Working a sink line from a boat allows casting to shore, and then getting the fly to follow the steep contour downwards. I get a lot of strikes in 20+' water, which is just 40'-50' offshore many places.
With a little practice, you can get the fly to just skim over the bottom - if it weeds up, speed up the recovery. A hook-up fly works a bit better, but I still loose a fair bit to the bottom. It's effective, though.