Rethinking the Wetsuit 153
symbolset writes "Apparently Australians have come up with the brilliant idea: if you don't want to be eaten by a shark, it's best to not go swimming in shark-infested waters in a seal costume. 'Scientists from the University of Western Australia, with designers Shark Attack Mitigation Systems (SAMS), have unveiled two new wetsuits that they say could save lives in the water. Based on a breakthrough discovery that sharks are colour-blind, one wetsuit, labelled the "Elude," is designed to camouflage a swimmer or diver in the sea. At the other extreme, the "Diverter" sports bold white and dark-blue stripes, and is intended to mirror nature's warning signs to ward off any potential shark attack.'"
Minimal danger (Score:4, Insightful)
We're here on the West Australian coast, which is now the deadliest coast in the world
Yes, the deadliest coast in the world. 16 attacks (not all fatal) in... a decade. And how many millions swim off the coast every year? Even if you take Australia as a whole, on average the number of people killed by sharks per year is: one [taronga.org.au]
If you want to avoid being attacked by a shark, I'd like to sell you this tiger^h^h^h^h^h shark repelling rock. It's much cheaper than a brand new wetsuit, and statistically equally as effective!
Re: radical new technology (Score:5, Insightful)
Most predators use a chomp and shake technique, while avoiding puncture wounds is a good thing, having a 14 foot shark shake you like a rag toy is going to spoil your day
Re:Minimal danger (Score:5, Insightful)
This is a conditional probability - you need to account for the degree of exposure to see how that overall fatality rate relates to a specific individual. Since shark attacks are exceedingly rare on land, the overall fatality rate is skewed down by the overwhelming number of hours spent on land (which contributes 0 probability of shark attack). This is different from things like mosquitos, where (nearly) everyone is at risk of a mosquito bite all the time. The overall probability of being killed by a shark is
.999*(low risk) + .001*(very high risk) = average low risk. But since their overall fatality rate is slightly below construction workers, that means that 0.1% of the time they're facing a risk of death hundreds of times higher than what construction workers face. That's what they're complaining about.
p = [ (hours on land)*(zero) + (hours on water)*(chance of fatal shark attack) ] / (hours total)
So say the entire population (including everyone who's landlocked) goes to the beach an average of 2 times a year and spends a total of 30 minutes in the water, and suffers 1 shark fatality per year. But the average surfer goes to the beach 3 times a week and spends 2 hours in the water each time. Then the average fatality rate for surfers is equivalent to 312 fatalities per year for the entire population. In other words, if the entire population spent as much time in the water as surfers do, you'd expect to see 312 shark fatalities per year. (The actual rate is lower since a disproportionate number of hours in the water is contributed by these surfers vs. casual beachgoing swimmers.)
Same thing happens for police officers, who are frequently criticized for complaining about the dangerous situations they encounter when their overall fatality rate is lower than for construction workers. But construction workers are exposed to their danger 40 hours a week. As best as I could determine, police officers spend only 10% of their time on patrol, and probably only 1% of that time is in what would be considered a dangerous situation (chasing and apprehending a resisting suspect). So whereas construction workers are exposed to a constant level of moderate risk, police officers face a low risk 99.9% of the time, then an incredibly high risk the other 0.1% of the time.
Silhouette (Score:5, Insightful)
Whoever came up with this doesn't know much about sharks.
Most sharks and other carnivorous fish hunt from below, looking upward for their prey's silhouette against the bright and shiny sea surface. Doesn't matter what color your wetsuit is, it's not going to break up your silhouette.
In fact, the reason prey fish have silvery sides and bellies is to blend in with the shiny sea surface. You could try a reflective websuit, I suppose, but then you'd look even more like a fish.