Investigation says lap bar was not checked in 2004 Hydro death at Oakwood
Posted
No-one checked to ensure a teenager was securely strapped into a water ride minutes before she plunged 120ft to her death, an inquest has heard. Hayley Williams was with family and friends when she fell from Oakwood's Hydro ride while on holiday in Pembrokeshire in April 2004.
Read more from the BBC.
Related parks
- More
- 1
- 2 of 2
It's really not that different from, say, Snake River Falls at Cedar Point. It's a little taller and it's a little steeper, but that doesn't matter. What matters is the force profile, and that can be done safely. And if going over the drop only lightly secured scares the living crap out of some riders, that's perfectly OK, as that's what the ride is supposed to do.
HAHAHA. A little taller and a little steeper? Since when is 80 feet and 121 feet a tiny gap between height for a flume ride, or ANY ride for that matter? And since when was 78 degrees (Perilous Plunge) just only "a little steeper" than 50 degrees (Snake River Falls/White Water Landing)? You say it doesn't matter that these rides are much taller or steeper. It does matter, it's for these reasons why these kinds of G's (or lack of) are produced.
And I don't get this whole "force profile" thing you're putting out. You don't get airtime going down Snake River Falls, said from personal experience. On these giant Intamin flumes, the design is purposely meant to exert powerful G's on the riders. Again, the whole selling point of the attraction.
But it is not supposed to kill people. That is !ok.
You're right. But you make it sound like two or three people die a month riding these flumes. That's not the case. In both cases, both riders were much too light and thin or too large and heavy, outside the safe parameters Intamin set for these rides. Both parks were at fault for not enforcing these safety rules. I'm not saying Intamin has no fault in this, because there have been so many incidents regarding rider ejection and fatality because they were not secured by the lap-bar, but I don't know what you're getting at.
*** This post was edited by kRaXLeRidAh 5/17/2006 8:40:08 PM ***
Honestly, All the cases of that restraint failure have been due to the bar not being in proper possition. Weight is not the cause but can contribute to a false looking proper possition.
True. But the problem is that there's simply no way to tell when the lapbar is in "proper position." The B&M hypercoasters, for instance, have a computer monitoring system. The Arrow and Morgan hypercoastes have lapbars that won't click until they're in a "safe position." Other coasters have seatbelts to determine how far done a lapbar needs to be. The Intamin t-bar has none of these, and that's a huve oversight on Intamin's part.
Apparently Intamin sets a body dimension and/or weight restriction on their rides. That's fine and all, but how the heck is that supposed to be measured? Combine that with a rather ineffective restraint system and you've got problems...and we've seen the results.
-Nate
I suppose you could simply figure out the bar position that will adequately secure the smallest person who could possibly ride, and call that the minimum. But if you do that, why bother making the restraint adjustable? Why not just have the restraint close only to that point and call it good for everybody? You really can't have it both ways. Either you have the adjustability so that you can accommodate a wide range of riders, or you have a system you can check mechanically or electrically. If you have a system that can check itself, either you are going to mechanically allow a small rider to go out inadequately restrained, or you are going to gain nothing at all by taking the restraint down smaller than the maximum allowable position. If you are going to rely on the restraint being put into the "proper position" you need to determine the proper position based on relative measurements, train the operators accordingly, and make them check visually. You can't do this with an interlock. Intamin understands this, and that's one of the reasons they didn't build an interlock into their design.
kRaXLeRidAh, my point is this: The height, speed, and angle of the drop are, in this case, unimportant when it comes to figuring out what the ride is going to do to people. The only things that are important are the linear and angular accelerations...in other words, the acceleration of the ride vehicle as it rolls over the top of the drop. Once it is over, it's essentially in free-fall until it hits the curve at the bottom of the drop, and the size of that curve is going to be determined by the speed of the boat and the allowable acceleration at the point where you bring the people back into their seats. The point of contention is the very top of the drop, where the boat gets dragged down faster than gravity will carry the people. You can predict where gravity is going (that's where the people go) and you can predict where the boat will go. To keep the ride safe, you limit the divergence between those two paths. To keep the ride exciting, you make sure that there *is* a divergence between those two paths. But that divergence should be significantly less than the height of the seat back, otherwise the boat is going to beat the riders to the bottom of the drop. And that is a Bad Thing™.
I wish I could take a video camera on board Magnum XL-200 sometime to demonstrate how this works. Sadly, the park doesn't allow it. And if they knew the nature of the demonstration, they would ABSOLUTELY not allow it. :(
--Dave Althoff, Jr.
Either you misunderstood or I wasn't clear. Obviously restraint systems like this need to be adjustable, as they need to be able to secure people of a wide range of shapes and sizes. The "proper position" is generally considered to be the point at which the lapbar is down as far as possible (touching the rider's lap, for instance). That's essentially standard on most coasters with adjustable lapbars, from PTC wooden coaster trains to B&M hypercoaster trains. That's why manufacturers specify that lapbars need to be down as far as possible and that physical restraint checks are necessary. That way, at least in theory, a lapbar secures a small person just as well as a larger person.
The problem is that Intamin also specifies that there is such a thing as "too large" for their restraint system, but completely fails to provide any way for an operator to tell what, exactly, is "too large." Other manufacturers have a system that determines this. B&M hypercoasters, for instance, have a computerized system that prevents the ride from being dispatched unless all of the lapbars are down past the "safe point." If a rider is too large to allow for the lapbar to be pulled down past the "safe point," he/she cannot ride. PTC lapbars don't start ratcheting until they're past the "safe point." B&M inverted coasters have a seatbelt that cannot latch unless the OTSR is in a safe position. The Intamin t-bar has *nothing.* It will lock in any position, including those positions Intamin considers "unsafe." Intamin specifies that riders of a certain size cannot ride, but their restraint system doesn't provide any way for operators to know what's too large. That's a huge problem, and has been a contributer to three larger people being thrown from their rides. I'm not sure how you can argue that you can't determine a "proper position" with with an interlocking lapbar, since nearly every other lapbar out there works that way.
-Nate
The boddy straightens durring airtime making a adustable restraint moot and a improperly adjusted seatbelt dangerous unless the body is forced to remain in a Z possition (B&M Speed coasters by tilting the rider slightly back and having a full wrap around of the torso therefore GUARANTEEING The bar stays over the riders upper thighs)
Buzzbars for example are always over a riders thighs no matter a riders size, If the rider can get under it, IT's proper, The heigth limitations are a more a where the head relates to the sides, bar and back of the seat more than anything.
GEE, They still make PTC Jr.s with Buzzbars and just about anyone can ride safely.
IMHO these weren't accidents where someone was doing something wrong, The bar wasn't over the upper thighs.
My experience with S:ROS and MF when I could ride them was that the bar would seem to be proper in the station but upon climbing the lift and being force back into the seat and possibly slightly upward that I'd have a few inches to pull the bar down and I would and did on several occations.
Perhaps the question is, How MANY AREN't or HAVEN't been killed because people were/are smart enough or concious enough to pull the bar down further themselves?
Of course IMHO there were other flaws such as floorboards allowing the legs to straighten
The new MAXIMUM RULE or Deivices only serve one purpose, To limit the size of the rider. It doen't correct the problem and Guarantee its in proper possition.
For legal reason, I have to state the above as fiction but given the chance to demonstrate it would be easily obvious.
Chuck
The "maximum size rule" (as you refer to it) is a separate, but also large problem. You're correct that it only limits the size of the rider and does not fix the problem with straightening your body. However, I don't think it was merely coincidence that three people thrown from Intamin rides were, apparently, too large to ride. A go/no go system (which is what CP installed on Millennium Force) would have prevented those incidents. What we have here, I think, is a situation where at least two restraint problems exist and they have worked together in the past to result in some unfortunate accidents.
-Nate
HAHAHA. A little taller and a little steeper? Since when is 80 feet and 121 feet a tiny gap between height for a flume ride, or ANY ride for that matter? And since when was 78 degrees (Perilous Plunge) just only "a little steeper" than 50 degrees (Snake River Falls/White Water Landing)? You say it doesn't matter that these rides are much taller or steeper. It does matter, it's for these reasons why these kinds of G's (or lack of) are produced.
Those G's also tend to have riders' legs against the bottom of the lapbar padding until almost halfway down the drop. Think of it as sustained ejector airtime. It's a very different ride than most shallower angled flume rides, even before the major splashdown.
How do you determine whether the lap bar is in the "proper position"? My argument is that with an adjustable lap bar, you cannot determine mechanically whether or not the lap bar is in the "proper position".
With an adjustable lapbar, it makes sense that only the minimum locking position can be determined mechanically. The rest of the locking positions would have to be verified visually.
To me, this makes sense: the first locking position is the minimum locking position for the largest rider, the lowest locking position is the position that would secure the smallest rider. The interlock, if one existed, would at least determine that the restraint is in the minimum position. The visual check would ensure that the restraint was locked down to the rider, beyond the interlocked position.
- More
- 1
- 2 of 2
You must be logged in to post
