Just crunched our numbers from the last fill up and hours on engine and it comes in at 1.2 gallons per hour. That's at 8 point something knots over ground with the current, 6 point something against, and 2700 RPM on the 100hp Yanmar.
My first stab at how much fuel the Honda Element uses was way off...it takes 45 minutes to go 32 miles to the next town down the road, so it's actually pretty close to 1.1 gallons per hour.
Our boat is perfect for us; not too big, not too small, it's juuuuuust right