River rapids ride

A river rapids ride (or river rafting ride) is an amusement ride that simulates whitewater rafting.

The river rapids ride concept was proposed by Bill Crandall (general manager of AstroWorld in Houston) and developed by Intamin. AstroWorld introduced the world's first river rapids ride, Thunder River, in 1980 and popularized a concept which can now be found at most major amusement parks. Despite being an incredibly popular attraction, AstroWorld's Thunder River (being a prototype) was initially plagued by issues that were corrected in the first few seasons of operation. The boat bumpers were re-designed, portions of the wide river channel were narrowed or barricaded to prevent boats from bottle-necking or getting caught in a backflow, and a planned whirlpool effect was scrapped.

Many modern river rapids rides feature a much narrower river channel as well as smaller boats (6 seats as opposed to 12 seats). Some are heavily themed, while others may present a natural setting for added realism. Multiple manufacturers have introduced new elements to the rapids ride concept: a vertical lift system, shoot the chute-style drops, and a whirlpool feature.

River rapids rides feature circular rafts with two main components: the fiberglass body in which passengers are seated and the rubber ring upon which the body is secured. The rubber ring provides buoyancy as well as shock absorption for when rafts collide with an obstacle during the course of the ride or with each other. Most rafts hold between six and twelve passengers, seated in groups of two or three depending on the manufacturer of the ride. Riders face toward center of the boat and are usually secured by a lap belt. Some rafts feature a circular metal bar in the middle of the raft; this gives passengers a place to grip or brace their feet. Some parks include a space for stowing small items in the center. The floor of the raft body is generally above water level to allow drainage. Most parks require riders to be 36 inches or taller.

Generally, the station starts at the highest point on the ride, with the river channel having a slight gradient to it for the remainder of the ride. A lift hill then brings the boats back up to station level at the end of the ride. This is usually also the point where the ride's main pumps are housed, bringing the water up from the low point and back up to the high point. The gradient on the river channel provides the water with its flow and pace. This also has the interesting side effect such that when the ride's pumps are switched off at the end of operation or in an emergency, the water naturally flows back to the end of the ride where it collects, leaving the majority of the ride's river channel empty and drained until the pumps are turned back on. All Intamin permanent (and most other) river rapids rides feature a connected lake of some sort at the end of the ride before the lift hill. This is sometimes used to store broken boats. Its main purpose, however, is to help store the large amounts of water that collect at the end of the ride (before the lift hill) once the ride's main pumps are turned off. This is the water that would have been circulating around the ride when it is in operation. When observed, you can usually see the height difference in the water level in this lake from when the rides pumps are turned on, to when they are turned off. This effect is usually less noticeable if an already existing larger lake is used for the ride's water storage. Generally, a longer rapids ride will need a larger lake, as there will be more water to store once the ride's pumps have been turned off. Depending on the size and length of the river rapids ride, it can take up to 15 minutes to fill the ride's channel up from empty once the pumps have been switched on.

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