As Boulder Bronco mentioned, an "ice boat" is typically a sail boat on skates, although they can be configured differently.
Check out
http://www.iceboat.org/faqiceboat.html for pictures and details.
An ice boat on Winnipesaukee is usually useless as they are good on flat, clean ice only. Not something we are used to here...
They are non-powered and do not float. They are definitely not meant as a safe means of transportation. They are quite tippy. The first picture by RI swamp Yankee were hovercrafts on Alton Bay. The second? Who knows? A bit airboat? A bit ice boat? An accident waiting to happen?
