@colorblindcowboy
"Reasonable" begs the question for what purpose.
If you want to #sail round the #world in #recordbreaking time then 75ft could be the answer.
https://www.theguardian.com/science/2005/feb/10/thisweekssciencequestions4#:~:text=Ellen%20MacArthur's%2075ft%20trimaran%2C%20B%26Q,circumnavigate%20the%20world%20this%20week.
If you want to sail some of the narrower #rivers and #dykes of the #NorfolkBroads then I'd say 17ft
https://gregafloat.org.uk/seahawk/2006waxhamcut.php
