In general every foreign vessel regardless of gross tonnage or draft, and every American vessel under register, entering, departing or traversing the waters of a state must employ a pilot licensed by the state in which the vessel traverses.
The State sets the pilotage rates and makes the laws which govern pilotage. These laws are in effect in order for states to ensure the safe passage of vessels and to protect their waterways and shores. The specifics of these rules including the boundaries of state waters may be found in the web sites listed below.
MASS. PILOT LAWS http://www.mass.gov/legis/laws/mgl/gl-103-toc.htm
RHODE ISLAND STATUTES http://www.rilin.state.ri.us/Statutes/TITLE46/INDEX.HTM
BLOCK IS SOUND RULES http://www.rilin.state.ri.us/statutes/TITLE46/46-9.1/INDEX.HTM
RI PILOTAGE RULES & REGS http://www.dem.ri.gov/pubs/regs/regs/coastal/pilot09.pdf
Vessels Required to Employ R.I State Pilot
Vessels Required to Employ Mass State Pilot 103-21
New York State Pilot Laws NYS
Connecticut State Pilot Laws view
Buzzards Bay Statutes and Regulations oilsprep
Rhode Island Yacht special exemption "Any yacht that is less than 200 feet in length overall, which is not engaged in commercial operations, does not require a state pilot."
New York Yacht Policy 011706 "All foreign flag yachts 100 feet in overall length and over shall be required to take a state pilot."