Coasters and You- How 'Water Dummies' Work

Image from NBC10

Water Dummies and You- 
Why one falling off isn't a reason to panic.


Okay people, it's time for a rough and dirty crash course on coaster dummies combined with some easy math.

Everyone loves to panic and panic they have, since two water dummies fell from a the Gale Force coaster at Playland's Castaway Cove in Ocean City, New Jersey.

In essence the story reads like you'd expect- Playland's Castaway Cove was doing it's safety testing, this is accomplished by using 'water dummies' which every theme park uses. They leaked, lost mass and became loose. This allowed them to fly off the coaster and damage the roof of a nearby hotel.  This story came across my dash, shortly followed by the rounds of internet hysteria.

Direct caption from BroBible

Naturally, this has lead to some people fear-mongering, then having a fit over the safety of roller coasters without even having a clue what a 'water dummy' is. This response naturally made my eye twitch. It had me groaning at my phone, using that famous line from a commercial 'That's not how it works. That's not how ANY of this works!'.


So now, I'm here and I'm going to give you a down-and-dirty explanation of what happened.

Image from The Point

What is a Water Dummy? 
Water Dummies are either soft or hard plastic items which can be filled with water to simulate the weight and presence humans on a thrill attraction. More advanced versions can have testing items attached such as g-force monitors and speed sensors.

 (Fun Fact- Humans are 60% water)

The image to the right is a version used by Cedar Point, a hard-plastic water dummy. This is the most common version which you'll see at most amusement parks. This model has been in use for years.

 This is a soft-sided water dummy.  They are made of thick plastic but collapse flat when not filled with water for easy storage. The water is what gives them the 'human' shape. These are the type of water dummies which became loose from the Gale Force coaster.

 As you can see, without water to create mass- These are the same as very thick plastic bags, which is exactly HOW they became loose and exited the coaster before the end of the ride.

Breaking it down: For this example, I'm going to use a basic kitchen bag as everyone know how those work.

  Take a plastic bag, any type of plastic bag from your kitchen!  Fill this plastic bag with some water and seal it shut. Now, imagine putting that in the front seat of your car and drive around. Nothing happens. It's simply a plastic bag sitting on your car seat!
 Now, say your bag had a leak and you go driving around. The bag will empty of water, make a mess. Imagine you opened your windows because it's a lovely day outside? What happens to that bag now, It's going to fly EVERYPLACE around your car until it finds the open window and becomes litter on the highway.

That's exactly what happened. An expensive plastic bag had a leak, deflated and when subjected to speed.. flew away.


Are Coasters Safe? 

The underside of a coaster train, Griffin at BGW

In general, Yes. These are multi-million dollar investments. They're hideously expensive. So expensive that you do everything in your power to keep things running safely, because a running coaster brings people to your park.

 Every state, especially those with a high tourist factor, often have strict rules and regulations around amusement rides. Each one must go though rounds of test hours before opening each season. Each coaster must be inspected and signed off on the amusement park (and in some states) the state in question. Each park inspects their coasters daily before an that park opens for business. Each coaster has morning 'test runs' to make sure everything is operating properly.

Remember, these are businesses who run on both their reputations and their rides.

So what to do if  you still have concerns?

Coasters are like anything else, built to be safe for as many factors as they can calculate into the design. If your that worried I'd suggest you do some research before riding. Learn how coasters work, find out about the design and testing processes they go though, look up safety regulations in your state or the state your travelling to. Find out about the track record of the park in question.