So, 10 days to make up for an entire summer....
The summer has been for 15 weekends, (but you did get one weekend of boating in), so assuming the average boating weekend would only be one day, at about 7 hours of boat/fun time, that works out to only 14 days/7 hours per day. So, if you do 10 days at 9.8 hours per day, you've made up for the entire summer.
Piece of cake!