Mass. Gen. Laws ch. 102, § 21: Powers of harbor masters

Section 21. The master of a vessel within a harbor for which a harbor master is appointed shall anchor his vessel according to the regulations of the harbor master, and shall move to such place as he directs. The master of a towboat having a vessel in tow and a pilot having a vessel in charge shall allow such vessel to anchor only in such place as the regulations of the harbor master provide for anchorage.