The Boater's Guide of New Hampshire: A Handbook of Boating Laws and Responsibilities
The Official Boating Handbook of the New Hampshire Marine Patrol - Web Version
Table of Contents
State law requires that scuba divers or snorkelers display a diver-down flag to mark the diving area. Divers and snorkelers must stay within 75 feet of their diver-down flag. Vessel operators must stay at least 150 feet away from a displayed flag. Two types of flags indicate diving activity.
A rectangular red flag with a white diagonal stripe used to indicate diving activities are in progress on New Hampshire state waters
A blue and white International Code Flag A (or Alfa flag) displayed on a vessel engaged in diving operations on federal waters