:. . . Every paddle is operated
: by a paddler, and the variety among paddlers is ENORMOUS.

That is the very reason that three are many different golf clubs, too. A golfer may have his clubs custom fitted, or use off the shelf clubs, but the factory producing them knows the loft produced from each club, and designs their clubs to meet certain expectations. Some clubs are designed for golfers who slice, and others for those who hook.

I'd expect the same for kayak paddles. A strong kayaker can use a larger paddle for a longer time when compared to someone who is weaker. But it should be possible for both paddlers to have efficient paddles in sizes that fit them.

There is no real magic, though. A strong paddler with a large paddle is going to be able to move more water, and the forward force that paddler exerts will be greater than what a weaker paddler could deliver.

: It's wrong to expect that there is one optimal paddle or even to expect that
: a specific paddler will be most efficient with the same paddle as other
: variables are altered. But it's correct to study different paddles and to
: try to understand why they are different.

An area which has not been explored is the concept of matching two paddlers in a tandem canoe or kayak. This is an important element in marathon canoe racing, and probably ignored by most people. In tandem kayak where the paddlers are fairly close together, the paddlers muct paddle at the same cadence to avoid one paddle hitting the other. This is not a problem in longer kayaks. While canoe paddlers are far enough apart that they won't bash each other's paddle, they will frequently paddle to the same cadence so that the power is evenly applied. Some paddle three or four strokes to a side and then switch sides. Both paddlers would need to do this together, and so they would need the same cadence.

Since cadence and synchronization are elements in this equation, it would seem that some thought should be given to supplying a larger paddle to the stronger paddler. Then, assuming both paddles were of equal efficiency, the two boaters could paddle with equal endurance. The stronger one owuld put out more horsepower during the race, and the other would put out less, but the combined output would be maximized during the time of the competition.

These aren't exactly new ideas. people have been paddling for thousands of years, and paddles have evolved a lot during that time. But older styles are still used. That is partly because there is no big difference, and partly because the older styles evolved for reasons other than efficiency. Until recently (past 50 years or so) paddles were made of wood. If you didn't have the ability to create wide planks and then shape them into paddles, you used narrow boards, or flattened the edges of branches or saplings. It was far easier to make a narrow paddle than to make a wide one.

Just a thought.

PGJ