Wonderfully Made

10/05/2019 • View profile

I was watching Michael Phelps doing the Australian crawl in an Olympic replay and noticed that a swimmer doing this stroke creates a wave similar to that of a ballasted sailboat as it travels in the water, and this winning style may have contributed to Phelps success. This wave theory is what Hewitt Schlereth is talking about in his book titled "How To Buy A Sailboat" when he says that "the faster she travels, the longer the waves she makes, and there comes a time when she is making one wave: one crest of the wave is at the bow and the other at the stern " and that "this is the longest wave she can make, and she can only travel as fast as this wave..." Mr. Schlereth points out that the formula for determining the speed of the wave in knots, and of the sailboat creating it, is 1.34 times the square root of the length of the wave, which would be approximately the waterline length of the boat.

I propose, and surely it has been observed by someone else, that this explains why a taller swimmer can swim faster than a shorter one. Mr. Phelps is 6' 4" tall and postulating the extra length of his feet when extended would add 8 inches to his submerged length, and not counting his arms, which I am calling his "propeller", Phelps' maximum speed can be determined as follows: 1.34 x square root of 7 feet = 1.34 x 2.65 = 3.55 knots; and 3.55 knots x 1.15 mph = 4.08 mph. If you follow these calculations, you can easily see how a shorter person using this stroke would be a slower swimmer.

You could look up Phelps' fastest time for a hundred meter Australian crawl to see how fast he can really swim, but it appears that this wave formula could have some real time application in the swimming world as well as in the sailing one. This is why most of the newest racing sailboats are built with as long a waterline length as possible. The formula does not apply to boats that "plane" on top of the water such as traditional speed boats, as it applies only to those creating a "displacement" wave, where the boat or swimmer is in the water, as opposed to being on top of the water. This formula also explains why many of the ocean racing sailboats are designed to plane on top of the water as much as possible.

It is fun to combine faith and science in considering how we are wonderfully made in the image and likeness of God.

"How precious to me are your designs, O God; how vast the sum of them!" Psalm 139:17

http://www.usccb.org/bible/psalms/139