Yea.... I was a bit surprised too.
The difference in speed between the two is something like 0.2 mph.
http://www.hobiecat.com/community/viewtopic.php?t=7704
Take the distance of launch to the pier for example..... which is 0.7 miles. Average speed of 4mph, it takes
0.7 = 4X, X=0.175 hours = 10 minutes 30 seconds
At 4.2 mph
0.7 = 4.2X, X=0.167 hours = 10 minutes 2 seconds
So you get to reach the pier 28 seconds sooner in a revolution if both boats start from the launch at the same time.
Or, putting it a different way, the Revolution would be approximately 10 boat lengths ahead for every mile travelled.
Some difference, but not a whole lot.