We got good service
from Safe Harbor in Greenport. (They have two marinas
there.) We arrived with a broken shift cable, so maneuvering was tricky in their tight setup. They met us with five guys ready to fend, catch lines, and be as helpful as possible to get us safely into a slip. Their machine shop handles Yanmar
and had the cable we needed the next day. Quiet area, but close to attractions of Greenport (restaurants, carousel, shops, chandlery
...). We moved on so did not take advantage of other amenities they offer. Worth checking out.