Tubing, Bathing Suits, and Failure Prevention

Excerpt

All my grandchildren enjoy tubing. This relatively high speed water activity involves riding a “tube” that is being pulled behind a power boat at speeds approaching 20 mph. Modern tubes are not typically tubular, but are semi-flat objects (ours are disc-shaped) that are attached to the boat by a 75 ft long rope. There are handles on the top surface of the tubes and the riders, at least on our tubes, lay in a prone position while holding onto the handles. The tubes will plane on the water surface at speeds higher than about 10 mph, and if the boat is going over 15 mph, the tube will glide out of the boat’s wake whenever a “sharp”curve is executed. When the water is rough and boat’s path is curvy, hanging on to the tube becomes difficult because of the bounces, and the tendency for the rider is to slide across the tube surface. The combination of centrifugal forces, slick surfaces, and bouncing makes the ride fun, but difficult. The riders can slide off the tube and into the water. The magnitude of this tendency depends on the skill and strength of the rider and the speed of the boat. The grandchildren therefore want an “awesome” ride, which requires that they be on the verge of falling off the tube during virtually every turn. As the boat driver, I have to drive so that the combinations of bumps, turns, and speed are appropriate for the rider but, irregardless of the rider’s skill, awesome rides result in an occasional slip from the tube and trip into the water. …