A rule of thumb that I use is that human beings can began to feel differences in effort when they amount to 15% of the total effort involved. So by that reckoning the difference between 2.37 pounds of force and 2.1 pounds is on the threshold of detectability. The difference between paddling slow, say 2 mph, and fast, say 4 mph, is much greater, about a 350% increase in effort. So it's much easier to wear someone out by making them paddle faster than they are used to than it is by giving them a slow boat!

I can remember seeing more than once a big football lineman-type guy and his petite girlfriend showing up for a kayak tour. At the beginning of the day the guy is out in front of everyone and the girlfriend is lagging behind. By the end of the day the positions are reversed. It's all about technique. No one is strong enough to paddle all day just pulling with their lower hand.

Mike