The Boat Wreck Case Study Transcript
Wendy Sanders, PHD, PE:
This was a case of a boat rental. This particular case occurred out on Lake Powell. It's a massive lake that was formed by damning up the Colorado River. So it has hundreds and hundreds of miles of shoreline, thousands actually.
The person who had rented the boat drove that boat almost 100 miles on the day of the incident, all the way up past where they were intending to stay. And they were meeting some friends who were upriver, or up lake from where they were staying. They had a houseboat. They had driven their rented boat all the way up to where this houseboat was located. And shortly before nightfall, they decided to go back to their marina resort where they were going to stay the night.
The incident occurred shortly after 9:30, which is basically complete darkness. The gentleman operating the boat went out of the safely marked channel and as a result collided with an island.
Steve Rundell PHD, PE:
And so the boat essentially hit some ground underneath the water level that it couldn't see. That caused the boat to slow down and pitch forward, pitching occupants out in front of the boat. But it didn't stop the boat, so the boat kept moving and one of the occupants interacted with the prop while it was still spinning.
Wendy Sanders, PHD, PE:
First I was brought on board by the rental company. We were looking at whether or not the rental company had done anything in terms of this boat being rented to a person that would, in the end cause an accident. Eventually I got involved with how the boat itself may have contributed or not contributed to the outcome of the incident. And also looking at the environment, doing a full accident reconstruction and determining what actually happened.
Steve Rundell PHD, PE:
My job overall was to evaluate whether or not a guard, what's called a prop guard, would've prevented injuries.
Wendy Sanders, PHD, PE:
We didn't get a whole lot initially except for, here's the boat, here's the environment, let's figure out what happened on the night of that particular incident. So one of the things I did early on in the case was go out to that site, understand what the actual environment looked like in addition to looking at the boat itself.
Steve Rundell PHD, PE:
The first step was to obsess over the photos, obsess over the operative reports, and really understand the injury. And then the next step is saying, okay, now that we know what happened in this case let's address a hypothetical scenario where we build around different potential prop guards. And I dove into the literature and previous testing that's been done specifically to look at that and propeller type of contacts. You get discreet lacerations in the area as the propeller moves. So you'll see clearly where the propeller interacted. Alternatively, there could be linear type of wounds, lacerations, which are consistent with that skeg coming straight across. And that's kind of what we saw. We had the linear skeg pattern as superimposed. On top of that, we had the propeller marks.
One of the papers that we cited specifically involved the use of crash test dummies, looking at differences in injuries with and without a prop guard, and basically finding that at these speeds you have enough energy to result in significant injury, whether it's contact with the skeg or some other part of the boat, which would include a prop guard. My conclusion in this case was that a prop guard would not have necessarily reduced the injury severities or could have provided the potential for greater injuries or even death in this case.
So one of the things that Explico has built is a real-time boat water accident visualizer. And so we were able to, with the scan data and with the site inspection, we were able to build out the scene and put it into that visualizer so we could effectively drive the boat around the scene.
Wendy Sanders, PHD, PE:
'Cause this is a damned river, the lake itself that fluctuates sporting to how the dam is operating, the local rainfall. So some days when the lake is really, really high, there's a lot more available water space. But when the lake is very, very low, you will actually have hazards in the forms of islands or peninsulas that kind of are revealed just by the fact that the lake has now gone below a level where these things would actually become an issue.
Steve Rundell PHD, PE:
So one of the things the client was interested in is we want to look at variations in water level and see what you could see where this island, the shoal, would be at different water levels.
Wendy Sanders, PHD, PE:
We were able then to put the boat into the environment that existed that night and show that, okay, if you're sitting on the boat and you're riding at planing speeds, so then we know the attitude of the boat, the pitch of the boat, how it would sit in the water, is an island of that exact size and shape visible. The answer is yes.
Steve Rundell PHD, PE:
So it was very insightful to see how we used it. I think the clients got a huge amount of insight as to what happened, how it happened. We were just able to show them answers interactively on the fly. And it's why I think I'm, within Explico and within forensics in general, such an advocate to using those real-time tools. So that it kind of enables the artist to provide great things for us, but it also enables us to plug in physics and it enables us to share it instantly on the fly amongst attorneys, other experts, ourselves, and really help us work collaboratively.
