http://www.nh.gov/safety/divisions/n...estricted.html
Lake Winnipesaukee:
RSA 270-D, X - Speed limit of 45 mph during daylight hours and 25 mph during the period from ½ hour after sunset to ½ hour before sunrise. (See Revised Statutes Annotated, RSA 270-D - General Rules for Vessels Operating on Water, subsection X, for complete statute)