From NH RSA's:
http://www.gencourt.state.nh.us/rsa/.../270-d-mrg.htm
CHAPTER 270-D : BOATING AND WATER SAFETY ON NEW HAMPSHIRE PUBLIC WATERS
270-D:1 Definitions:
VI. "Headway speed'' means 6 miles per hour or the slowest speed that a boat can be operated and maintain steerage way.
VIII. "No wake area'' means an area where a boat is to be operated only at headway speed.
XII. "Wake'' means any disturbance created on the surface of the water as a result of combined vessel motion and hull displacement.