Gravity is a funny thing until it isn't. Most water park enthusiasts grew up hearing urban legends about a legendary slide that actually went upside down, a mythic beast of fiberglass and terror that supposedly lived at a place called Action Park in Vernon, New Jersey. The thing is, it wasn't a myth. The Cannonball Loop was real. It was a literal vertical loop slide at Action Park, and honestly, it remains one of the most baffling pieces of engineering ever approved for public use. It’s the kind of thing that makes modern safety inspectors wake up in a cold sweat.
People talk about "thrill rides" today, but they're mostly talking about calculated risks managed by supercomputers and magnetic braking systems. Action Park was different. It was visceral. The park, which operated in its original chaotic form from the late 70s through the mid-90s, was basically a giant physics experiment where the guests were the test subjects. The loop slide was the crown jewel of that experiment, even if it only stayed open for a few weeks at a time before the state or the sheer physics of the thing forced a shutdown.
The Cannonball Loop: A Lesson in G-Force
Building a vertical loop for a roller coaster is a solved problem because the riders are strapped into a heavy train that follows a fixed track. Building one for a person sliding on their bare back? That’s basically asking for a physics disaster. The loop slide Action Park famously debuted in 1985 was a 45-degree enclosed pipe that dumped you into a 10-foot vertical loop. It didn't look like a modern waterslide; it looked like something a kid would draw on a napkin.
Here's the problem: if you don't go fast enough, you fall from the top of the loop and hit the bottom. Hard. If you go too fast, the G-forces are high enough to cause serious neck strain or worse. When the park owners first tested it, they reportedly offered employees $100 to go down. The early testers came out with bloody noses and scratched-up backs because they were getting tossed around the interior of the tube like laundry in a dryer. They eventually had to add padding to the inside of the loop, but it was just blue gym mats haphazardly glued to the fiberglass. It was janky. It was dangerous. It was exactly what Action Park was known for.
Why We Don't See Them Anymore
You might wonder why, with all our modern technology, every Six Flags doesn't have a vertical loop slide. The answer is basically "human anatomy." Humans are not aerodynamic, and we aren't all the same weight. A 250-pound man and a 100-pound teenager will travel through a slide at wildly different speeds. In a normal slide, that just means one person splashes down harder than the other. In a loop, it means the lighter person might not make it over the crest.
WhiteWater West and other modern manufacturers have tried to solve this with the "AquaLoop." If you've been to a water park recently, you’ve probably seen these. They use a trap-door start to ensure you have enough initial velocity. Crucially, though, these aren't true vertical loops. They are inclined loops, tilted at an angle so that if a rider loses momentum, they just slide back down the side rather than falling vertically through the air. The original loop slide Action Park featured didn't have that safety margin. It was 90 degrees or bust.
The Legend of the Stuck Rider
There is a persistent story—often verified by former employees like those interviewed in the documentary Class Action Park—that the slide once had to be opened up because a rider got stuck at the top of the loop. When they cut the pipe open, they allegedly found several teeth embedded in the foam padding from previous riders who had hit the loop with their faces. While it sounds like a horror movie, the design of the slide almost guaranteed high-impact contact between the rider and the tube.
The Physics of Failure
The slide's design was fundamentally flawed because it ignored the "clothoid loop" principle. Most roller coaster loops are shaped like an upside-down teardrop. This shape keeps the centripetal acceleration manageable and consistent. The Cannonball Loop was a perfect circle. This meant the G-forces spiked at the entry and exit, making the ride incredibly jarring. It’s the same reason why early 1900s roller coasters with circular loops were notorious for giving riders whiplash.
Honestly, the fact that the state of New Jersey let it open at all is a testament to how lax regulations were at the time. The park was essentially its own kingdom. Gene Mulvihill, the park's founder, was famous for his "get it done" attitude, which often bypassed traditional engineering standards. He wanted a loop slide, so he built a loop slide.
Modern Iterations vs. The Original
- Action Park (1985): Pure vertical loop, fiberglass construction, minimal safety testing.
- Modern AquaLoops: Inclined 45-to-60 degree loops, trap-door sensors, constant water pressure monitoring.
- Safety Protocols: Modern slides will shut down if the water flow drops by even a fraction; Action Park relied on a guy with a hose.
The Cultural Impact of Action Park
It wasn't just the loop. The park was a collection of "what were they thinking?" moments. From the Alpine Slide that stripped skin off shins to the "Grave Pool" (the wave pool nicknamed for its frequency of rescues), the park represented a specific era of American risk-taking. It was a rite of passage for kids in the Tri-State area. If you survived a day at Action Park, you felt like a warrior.
The loop slide Action Park became the symbol of this lawless fun. Even though it was rarely open—it would often close after just one or two injuries—its presence on the skyline of the park sent a clear message: Anything can happen here. It was the ultimate marketing tool. You didn't even have to ride it to be terrified by it. Just looking at that rusted-looking pipe standing in the middle of a field was enough to give you a story to tell at school on Monday.
What Happened to the Park?
The original Action Park closed in 1996 after years of lawsuits and financial trouble. It eventually reopened under new management as Mountain Creek Waterpark. For a brief, glorious moment in 2014, the "Action Park" name was actually brought back as a nostalgia play. They even talked about building a new, modern version of the loop slide using sophisticated engineering. They eventually built the "Sky Caliber," a vertical loop slide where riders sit in a protective capsule. It was safer, sure, but it lacked the raw, terrifying energy of the original.
The era of "do it yourself" water park engineering is over, and frankly, that's probably a good thing for everyone's spinal columns. But the Cannonball Loop remains a fascinating footnote in the history of amusement parks—a monument to a time when imagination (and a complete lack of fear) outweighed safety regulations.
Actionable Insights for Thrill Seekers
If you're looking for that kind of intensity today, you have to know where to look. You won't find the original Cannonball Loop (it was scrapped decades ago), but you can still experience the physics that made it famous.
✨ Don't miss: Las Vegas Weather Degrees Celsius: What Most People Get Wrong
- Seek out "AquaLoop" installations. Manufacturers like WhiteWater West have perfected the inclined loop. You can find these at parks like Great Wolf Lodge or various Six Flags Hurricane Harbor locations. They provide the sensation of a loop without the "losing your teeth" part.
- Watch the Documentaries. If you want the full, unvarnished truth, watch Class Action Park (HBO). It features actual footage of the loop slide in action and interviews with the people who were crazy enough to ride it.
- Check the "Trap Door" Slides. The closest feeling to the original Action Park drop is any slide with a "launch capsule" (like the Vanish Point at Busch Gardens). The sudden loss of the floor is exactly how the original loop riders felt when they hit the vertical drop.
- Understand the Physics. Next time you're at a park, look at the shape of the slides. Notice how modern designs use banking and curves to keep your body centered. It makes you realize just how insane a straight-up vertical loop with no harness actually was.
The legend of the loop slide Action Park lives on because it represents the extreme end of the "what if?" spectrum. It was a mistake made of fiberglass, but it’s a mistake we can’t stop talking about. Safety is better, obviously. But there’s a small part of every thrill-seeker that wonders what it would have been like to stand at the top of that platform in 1985, looking down into a dark tube, and deciding to jump anyway.