As a rower, I tend to think less of other water activities like canoeing and kayaking and stand up paddle boarding. They are nice but less rigorous, etc., I think. They are good for the arms (and core) but do not use the strongest muscles in the legs as rowing does.
But there is a 120-mile canoe marathon you may want to know about, the Au Sable Canoe Marathon: www.ausablecanoemarathon.org/ .
The course starts at Grayling, Michigan (center of the state) and goes east to Oscoda on Lake Huron.
The 67th running of the race begins at 9 PM (yes - PM) this Saturday, July 26, 2014, with pre-race events and time trials starting the 22nd.
Many of the 80+ two-person canoe teams will finish at Oscoda between 11 AM and 4 PM the next day (current record 13:58:08). That is a lot of canoeing!
There are professional entrants and categories by age group and gender.
Learn more at the web site (above).
What events do you know of or participate in?