I scanned this photo today. Date unknown. Probably 1961, 1962. Lake Michigan.
I have a website with a page dedicated to the “Mitena”, a boat my family was involved with.
The Mitena page on my family genealogy site.

 

My father and his friends raced on the Great Lakes for many years. This is 12 meter “Mitena” at the start of the 1962 Chicago Mackinac race. The “Mac” (as it is known) was first run in 1898. At 333 miles, It is the oldest annual freshwater distance race in the world. Source- http://en.wikipedia.org/wiki/Chicago_to_Mackinac_Boat_Race