From .....
https://www.nhfishandgame.com/instruction.aspx?m=hs ......
"Unless the person shows proof of possessing a current year:
NH Hunting or Fishing License
NH Off Highway Recreational Vehicle of Snowmobile Registration
NH Boat Registration
A voluntary Hike Safe Card"
So, when you register your boat you get the same hiker rescue-off-the-trail service as the $25-NH Hike Safe card.