Rapids ride safety equipment feasibility

[Smiley]

There are risks with any option - but I do believe a safe system of restraint can be achieved. Compare a flipped raft without restraints - there's going to be a lot of momevement of people as it flips, potentially causing severe injury. Airbags in cars can mi's-fire (causing injury/death), but the benefits outweigh the risks.

It's a natural reaction to try and avoid a tidal wave of water coming at you - hence why people stand/move around inside the raft. (Of coure, not in Florida where it is usually welcome) Perhaps seat belts don't even have to be "locked" - are riders are less likely to undo their seat belt to stand up, compared to no seat belt??

Much as I'm a fan of Darwin's selection process, it's not a great legal argument.

 

[jibbsie]

There are risks with any option - but I do believe a safe system of restraint can be achieved. Compare a flipped raft without restraints - there's going to be a lot of momevement of people as it flips, potentially causing severe injury. Airbags in cars can mi's-fire (causing injury/death), but the benefits outweigh the risks.

It's a natural reaction to try and avoid a tidal wave of water coming at you - hence why people stand/move around inside the raft. (Of coure, not in Florida where it is usually welcome) Perhaps seat belts don't even have to be "locked" - are riders are less likely to undo their seat belt to stand up, compared to no seat belt??

Much as I'm a fan of Darwin's selection process, it's not a great legal argument.

but there have been multiple instances where people with seatbelts have gotten trapped because of struggling to undo those belts.

also the issue with the self releasing is differnt from airbags, a car has a battery with a built in generator so power isn't an issue as the car should always have power (given how reliant on the ECU the car is it probably wouldn't run if it didn't have power) but also in a crash the forces are very differnt from driving, pulling 10G isn't normal when driving, nor is being flipped but since rapids litterally is crashing through water the forces will probably look similar

 

[pluk]

If the issue you want to stop is people accidently falling in the water the only thing you need do is put doors on the gaps between the seats, then even from a standing position on the floor of the boat you are only ever facing over in the boat.

If you want to stop people deliberately jumping out of the boat, or putting them in significant danger by standing on the seats, well you can't really.

 

[Dhev123]

Would be super expensive, but what if rapids rides were retrofitted with rails, and new boats with wheel assemblies? While the boat wouldn't naturally rock anymore, the rails can have S bends and slight dips and hops to give the illusion of rocking - that way they could have a lap bar of sorts

 

[Skyscraper]

Would be super expensive, but what if rapids rides were retrofitted with rails, and new boats with wheel assemblies? While the boat wouldn't naturally rock anymore, the rails can have S bends and slight dips and hops to give the illusion of rocking - that way they could have a lap bar of sorts

The Mack Rocking Boat says hi

 

[Dhev123]

The Mack Rocking Boat says hi

Haha there we go then! AT takes notes

 

[Smiley]

but also in a crash the forces are very differnt from driving, pulling 10G isn't normal when driving, nor is being flipped but since rapids litterally is crashing through water the forces will probably look similar

A car crash will typically have 10x Gs (instantaneous) compared to a raft. I imagine all upturned rafts have very little kinetic energy. It's very easy to create a reliable energy source on a raft for this purpose.

FYI (I used to work on automotive critical systems), there's around 50ms to determine that a crash is occurring and deploy airbags (not all as some might impede exit if not required). A blink of an eye is somewhere between 3-6x that time.

Remember when driving - if you're going to crash, do it with something man-made. No-one ever won against a tree!

 

[jibbsie]

A car crash will typically have 10x Gs (instantaneous) compared to a raft. I imagine all upturned rafts have very little kinetic energy. It's very easy to create a reliable energy source on a raft for this purpose.

rapids have an insane amount of kenetic energy due to their weight, they weight multiple tonns (depends on the rapids) as the base plate is a thick steel disc to keep the center of mass down.

the problem is 2 problems I was trying to state, the problem of measuring it and the problem of powering it.

the measuring is a problem as what are the differnces between crashing a car and driving, quite a bit interms of acceleration, but on a rapids rides it may look much more like normal opperation, this is componded as the results will heavily be determined by the COM of the boat, the GM, the position of the sensor, the center of boyancy and how the water feels like, as turbulent flow is essentially random and unpredictable.

the powering problem is more a problem of having enough power, not storing it, the rafts have to actuate this reliease mechanism each time it is in the station, it will probably have to be able to recharge during opperation this is hard as the position and orientation of the rafts are unknown in the station, and dealing with high powered electonics (it will probably have to be able to produce a lot of power to quickly charge the batteries) isn't a good ides, not to mention the risk of water getting into the boat and shoring the battery causing a fire in the middle of a rapids

 

[Smiley]

??? High power electronics - presumably a solenoid that has to be open for seconds to let people open their belt. A battery shorting is not relevant - batteries don't short because the get wet.

It's much easier to determine whether something is upside-down than it is to determine if it's going to crash in the next 1/10 second. Where some people see problems, others see opportunities and solutions.

 

[neil_wilson]

It sounds like the people commenting in this thread are well informed about river rapids, and it's an interesting discussion. For anyone who's interested in rapids and hasn't seen it, here's the Health and Safety Executive's advice for maintaining and operating river rapids.

https://www.hse.gov.uk/entertainment/assets/docs/health-safety-river-rapids-rides.pdf

It's for parks rather than manufacturers, so it isn't directly relevant to this thread, but it might be useful context for some people.

 

[jibbsie]

??? High power electronics - presumably a solenoid that has to be open for seconds to let people open their belt. A battery shorting is not relevant - batteries don't short because the get wet.

yeah, I was thinking solonoids, but you have to realise solonoids can draw a tonn of power (like amps) the first one in RS list of solonoids (not a big one either) draws 70w (https://uk.rs-online.com/web/p/linear-solenoids/1770144),

lets do the maths with this solonoid, at 70W if it was on in the station for 20 secs gives 1,400 joules per solonoid

because of amusment saftey there would probably have to be 2 per seat, lets say 8 seats so 16 solonoids all together drawing a total of 1,120W and using 22,400 Joules of energy when in the station.

the solonoid acts at 12V, becuase bateries are weird they use Amp hours, we can convert this joules into amp hours (22,400/(V*3600) resulting in them needing 0.518 amp hours PER STATION STOP. using standard 18650's (which are about 2.6Amp hours)

you would need about 4 of them to get to the 12 V required level, as when increasing voltage you don't gain amp hours you could only then power it for only 5 station stops, you can add more in parellel to increase the amp hours (essentially amps add up in parellel, but volts add up in series) assuming 7 min cycle (6 min ride time 1 min station) for a 6 hour day (10-4) that is about 50 station stops per day, you would need about 40 18650 batteries in total just to power this for one day, this is a masive battery.

clearly you can't have one battery power this for one day you will probably have to charge it when in the station, lets calculate this. lets say it can charge for 40 secs in the station getting to 25,000 joules (a bit more for saftey margin) this would have to be a charging circuit able to produce 625W right next to water with people very close to it, quite a powerfull energy scource, if it was 12 V it would be 52 amps! (max house current is 13 Amps) .

It's much easier to determine whether something is upside-down than it is to determine if it's going to crash in the next 1/10 second. Where some people see problems, others see opportunities and solutions.

yeah it is easy to know if something is upside down, but that thing is if it is stationary, or moving in a known method. boats that are getting constantly hit by waves and turbulent water with unknown forces makes it much much harder, if you use a mercury swich, well what happens if that boat just hit a big wave, well now all the restraints are undone, the problem is differntiating between rolling over, and being bashed by waves, being fliped may look very similar to being on the waves.

 

[DistortAMG]

I feel that all of this use of solenoids, batteries and what not is over complicating things somewhat. That system screams of high maintenance and unreliability, especially operating in the UK, where we have large temperature changes between seasons and where things like this are usually stored outside all year round. For it to be viable in the UK, it needs to be retro fitted to existing attractions and work around the existing infrastructure.

The solution I mentioned earlier by having the boats with tall backs, preventing people from falling out, is great for preventing the issue of people falling out boats, it stops the problem completely. That gives hints to where the solution lies for the issue of rafts tipping up, which is by stopping rafts from tipping in the first place.

This option is of course, only viable for new rapids rides, but for the most part, Intamin have pretty much completely solved this problem too. Hydrodynamics, physics and just more robust old fashioned engineering have been instrumental to newer rapids rides and elmiminating this issue. We didn't have access to the advanced hydrodynamics, scientific understanding and extremely precise physics models we have access too today.

Managing channel gradients, placing 'rapids' within certain distances between each other, so the peaks and troughs of the trails work together as do any waves in physics, even your noise cancelling headphones, are a few techniques used.

In the event of a power failure, boats will always make it back, the boats are not travelling slower than the water, so it's impossible for the channel to drain before a boat reaches the end. You can put wheeled ramps on the wave makers to help a boat get over a rapid if a boat decided to break the laws of physics or left the station at the same time the pumps stopped. But for the most part, physics does and always has ensured boats get back aslong as pumps fail completely at the same time and no boats are sent after that fact. In a few cases where boats have tipped, it's due to lower water levels, so here, a more robust control and water level monitoring system will prevent any boats being let out onto the circuit without proper water levels.

The key to solving the issue is by fixing the problem. Which for the most part they have done. Rapids boats in a free trough may be unpredictable in their movement, but hydrodynamics, physics and science is very predictable.

Newer rides do have more advance elements which add an air of unpredictability for sure, but you just engineer deeper into the predictable parts to compensate and allow the air of unpredictability to always be managed.

 

[Bowser]

In the event of a power failure, boats will always make it back, the boats are not travelling slower than the water, so it's impossible for the channel to drain before a boat reaches the end

Whilst looking at the links to boats tipping I saw multiple videos of boats getting completely stuck so surely this isn’t true?

 

[jibbsie]

I feel that all of this use of solenoids, batteries and what not is over complicating things somewhat. That system screams of high maintenance and unreliability, especially operating in the UK, where we have large temperature changes between seasons and where things like this are usually stored outside all year round. For it to be viable in the UK, it needs to be retro fitted to existing attractions and work around the existing infrastructure.

the restraints on the smiler, saw, hyperia, rita, 13, stealth, swarm and many more use a form of solonoids to actuate the valve to open the restraints. besides, I would agree that any electricals would be not good in a rapids ride. *Edit, realised I missed not before good

The solution I mentioned earlier by having the boats with tall backs, preventing people from falling out, is great for preventing the issue of people falling out boats, it stops the problem completely. That gives hints to where the solution lies for the issue of rafts tipping up, which is by stopping rafts from tipping in the first place.

from what I am aware about, the taller back is more about preventing the boat from crushing if it flips, the taller back will allow for gaps to allow people to escape.

Hydrodynamics, physics and just more robust old fashioned engineering have been instrumental to newer rapids rides and elmiminating this issue. We didn't have access to the advanced hydrodynamics, scientific understanding and extremely precise physics models we have access too today.

Not really, the rapids are turbulent water, turbulence is effectively imposible to predict, models do exist so you can approximate them though but it won't be accurate, even if it was changing the speeds of the pumps can masivly impact how turbulent and how forcefull the rides are (typically the more water, the calmer the ride is)

Managing channel gradients, placing 'rapids' within certain distances between each other, so the peaks and troughs of the trails work together as do any waves in physics, even your noise cancelling headphones, are a few techniques used.

I think you are getting confused, this is mainly to do with waves, the water in a rapids ride is turbulent this effect has an impact, but as the turbulence is unpredictable and changes depending on the flow of water you could easily get into a senario where at differnt pumping speeds you have constructive interferance.

In the event of a power failure, boats will always make it back, the boats are not travelling slower than the water, so it's impossible for the channel to drain before a boat reaches the end. You can put wheeled ramps on the wave makers to help a boat get over a rapid if a boat decided to break the laws of physics or left the station at the same time the pumps stopped. But for the most part, physics does and always has ensured boats get back aslong as pumps fail completely at the same time and no boats are sent after that fact. In a few cases where boats have tipped, it's due to lower water levels, so here, a more robust control and water level monitoring system will prevent any boats being let out onto the circuit without proper water levels.

boats getting stuck is still a problem, unless it is at one of the slide things it is still quite a big problem.

I would check this video out, it is quite good and explains the details of rapids rides.

From: https://www.youtube.com/watch?v=8Nbwkjmqrcg