How do they keep people from falling off open water slides?


Most waterslides allow you to go at high speeds, but I’m curious how they prevent people from falling off even when the wall of slide doesn’t really go high up to catch people? Of course, there are people with different masses and heights, and also different clothes, so how do they calculate the necessary measurements such as water pressure, friction or slide length to keep people from falling off open water slides?

In: 2


It’s mostly Physics. But it’s not perfect. In very rare cases people *do* go over the sides. But usually you have to do something that messes up the Physics.

Find something like a stick you can throw like a spear. If you throw it pointy-end first it’ll generally stay going in that direction. If you turn it sideways and try to throw it that way, you might see it spin a little and TRY to go pointy-end first before it hits the ground. If we *dramatically oversimplify*, what’s happening is the wide parts have more air resistance when they’re moving, and the pointy parts don’t, so all the forces acting on the stick while it flies tend to twist it so the pointy end is facing forwards and it isn’t traveling sideways. I’m pretty sure if you go searching on Youtube about dart game Physics you’ll find explanations that aren’t oversimplified.

One more thing: inertia. If a thing is moving in one direction, it tends to want to keep going in that direction. Making it go a different way takes some force, and the faster it’s going (or the more mass it has) the bigger that force has to be.

The person’s body on the slide is kind of like the stick. If they started sideways they’d go a lot slower because they’d have a lot more resistance against the slide. So these slides have them lay a certain way and usually keep their arms up, since arms can act like rudders. That means if they tilt a tiny bit, the same Physics that makes a dart or a stick fly the “right” way pushes them back so they are feet-first. And since they’re moving pretty fast down the slide, it takes a pretty significant force to make them shift far to the left or right.

The cases where people have fallen off usually involve something weird like bumps in the slide. That can cause the person’s body to “catch air” or leave the slide. That’s bad because air does a much worse job of keeping them “feet first” and in the same direction than the slide, mostly because a person has a lot more mass than a stick or a dart. So when they’re in the air it’s a lot easier for them to go off-course, which means when they land they might be slightly off the slide, and if it’s far enough you get a disaster.

Which is why the super-fast slides do NOT have little ramps so you can catch air. They try to be as flat as possible. But if someone’s body is shaped just right, and they flex their muscles just the wrong way, and especially if part of the slide’s not been properly maintained, bad things can happen. Rarely. (Some slides do have little ramps but they tend to be much slower slides than I’m imagining. The idea is if you’re going slower your body is in the air less time so it’s much less likely you’ll go so far off course you fall.)

Or, if they try really hard, they can roll off on purpose. I don’t think that’s really in the spirit of your question, but that’s important too: in addition to the Physics, most people don’t want to fly off the slide, so if they feel themselves headed towards the edge they try to move their body to correct that motion. Physics works, but when you give it a nudge it often works better.

This is also why these rides usually have minimum heights, maximum heights, minimum weights, and maximum weights. Going outside those ranges may mean it’s easier for a person to go outside the planned Physics, and it’s not always fun to find out what happens if you color outside the lines.

1. Pick an upper and lower limit and don’t allow people outside that range ride it.
2. Design a little past that range anyway
3. Buy insurance

The simple answer is Engineering. They calculate what will happen for a range of heights and weights and model it mathematically long before a single piece is fabricated.

This is also why there are height and weight limits for water slides and they instruct you to adopt a certain position. If you don’t fall within the safe parameters, you don’t get on. If you aren’t following safety guidelines if you have an accident, they are less liable.

And sometimes all the engineering and design fails