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Shark attack at Cobblestones , Gracetown

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Created by esoom > 9 months ago, 16 Apr 2018
jbshack
WA, 6913 posts
24 May 2018 4:23PM
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Bara said..
Yes I was surprised by the rpela complete fail too. I thought it would just be reduced effectiveness like the shark shield. Different frequency different current though.

Trials were in series ie one board in the water at a time.

60% effective for just 15 minutes should have been the headline. Or 100% inneffective after 30 mins?Hardly compelling stuff and certainly not a viable "solution"


I would suggest that testing 5 products continually, one after an another, on only a hand full of sharks, whilst competing with cage divers that have 8 people in the water, and other testing going on im not surprised at their results. It would be interesting if they had showed the order in which products were tested and if the results wound down over time..

Its as i would have figured with the SS being a most powerful unit, but in reality their is still the small matter of being able to use the product comfortably with out the unit being turned of, or having to apply stickers to reduce the power. The simple fact that the SS stopped an interaction 40% of the time under those conditions is actually very good. I guess its a case of power vs comfort of use = product.

Dave was present for all the testing and has since leaving those completed more "real world" testing locally of Esperance and those details he will release once completed.

But yes Bara i completely agree with your comment about being sick of the politics of sharks..

For me still, very happy paddling with my Rpela..

I would suggest anyone who has any issues/questions to contact Dave directly..

jbshack
WA, 6913 posts
24 May 2018 4:37PM
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Legion said..
Nice link, Bara.

I'm surprised at the differences they observed between Shark Shield and Rpela. Maybe it'll stop bjshack harping on ... nah.



Interestingly enough their an entire section on the different ac and dc power plus outputs..

Legion
WA, 2222 posts
24 May 2018 7:16PM
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bjshack said..

Its as i would have figured with the SS being a most powerful unit, but in reality their is still the small matter of being able to use the product comfortably with out the unit being turned of, or having to apply stickers to reduce the power. The simple fact that the SS stopped an interaction 40% of the time under those conditions is actually very good. I guess its a case of power vs comfort of use = product.

I would suggest anyone who has any issues/questions to contact Dave directly..



Did you even read the report? It says the Rpela has a higher voltage gradient. I interpret that as being a more powerful unit. The report therefore expected the Rpela to produce a larger electric field. For whatever reason (that is not understood by the report authors or clearly also not by the product manufacturers), the Surf+ however produces a larger electric field.

It's my understanding the Surf+ stickers contain the electrodes, rather than wires in a routed cavity like Rpela. It's not my understanding that the stickers have some power reduction purpose. That makes no sense. Why would you design something that produces excess power that then needs to be dissipated, compromising battery life?

Contacting Dave isn't good advice. Independent testing is what is needed in this market. It's good to hear what Dave says about his product and what the other guys say about their product, but they are both biased and trying to sell their product so it has to be taken with a large grain of salt.

IFocus
WA, 582 posts
24 May 2018 8:17PM
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Legion said..



Did you even read the report? It says the Rpela has a higher voltage gradient. I interpret that as being a more powerful unit.


Power (really basic) is E x I = P

Voltage levels are required to overcome the circuit impedance for current to flow but is not a measurement of power.

In this case what is the important measurement is V/m or the distance / strength a voltage is measured from the electrodes.

The other factors are Repla is a pulsed DC (lower impedance) and SS AC which is a higher impedance source but at a lower frequency will reduce impedance of the circuit.

Clear?

The numbers clearly show the Repla as a lower powered unit.


I don't understand given all the controls around testing that they do not measure the wave form and V/m real time but continue to imply.

Legion
WA, 2222 posts
25 May 2018 6:54AM
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bjshack said..

For me still, very happy paddling with my Rpela..


This study shows that you are just as safe saving your money and using the wax or magnets. I'll bet you were one of those guys on here spruiking the magic hologram bracelets too.

Legion
WA, 2222 posts
25 May 2018 6:57AM
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Thanks IFocus. Should have paid more attention in class. I also don't understand why the makers don't set up a test rig and vary some of the parameters to maximise the strength and range of the field.

TimKay
752 posts
25 May 2018 10:32AM
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Has anyone done any tests to measure the placebo effect of some of these units
Surely they must now come under this category
The amount of live testing they have done would make a lot of the science defunct especially with the more expensive rpela product.
But if you think your safe and your heart rate is low while your tea bagging on your board then the shark will then think your a respected water man like a certain person that is a forum expert (including swellnet) on the Great White Sharks.
Hence the placebo effect

Bara
WA, 647 posts
25 May 2018 10:38AM
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jbshack said..

Bara said..
Yes I was surprised by the rpela complete fail too. I thought it would just be reduced effectiveness like the shark shield. Different frequency different current though.

Trials were in series ie one board in the water at a time.

60% effective for just 15 minutes should have been the headline. Or 100% inneffective after 30 mins?Hardly compelling stuff and certainly not a viable "solution"



I would suggest that testing 5 products continually, one after an another, on only a hand full of sharks, whilst competing with cage divers that have 8 people in the water, and other testing going on im not surprised at their results. It would be interesting if they had showed the order in which products were tested and if the results wound down over time..

Its as i would have figured with the SS being a most powerful unit, but in reality their is still the small matter of being able to use the product comfortably with out the unit being turned of, or having to apply stickers to reduce the power. The simple fact that the SS stopped an interaction 40% of the time under those conditions is actually very good. I guess its a case of power vs comfort of use = product.

Dave was present for all the testing and has since leaving those completed more "real world" testing locally of Esperance and those details he will release once completed.

But yes Bara i completely agree with your comment about being sick of the politics of sharks..

For me still, very happy paddling with my Rpela..

I would suggest anyone who has any issues/questions to contact Dave directly..


Lol i think one thing we can draw from the study though is that if dave had jumped in the water with his repela for the ultimate proof of confidence there is a 97% chance he wouldnt be with us now!

not sure how you can have any confidence in the rpela after this study.

LateStarter
WA, 589 posts
25 May 2018 10:49AM
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The Government backed option is up to 60% effective for minutes, 0% effective after 30 minutes.

The locally made version, as championed by the salesmen on this forum is less effective than chilli flavoured wax.

As someone mentioned weeks ago, you might as well wear a letterbox on your head.

TimKay
752 posts
25 May 2018 10:55AM
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LateStarter said..
The Government backed option is up to 60% effective for minutes, 0% effective after 30 minutes.

The locally made version, as championed by the salesmen on this forum is less effective than chilli flavoured wax.

As someone mentioned weeks ago, you might as well wear a letterbox on your head.


Don't forget a salesman on swellnet as well

jbshack
WA, 6913 posts
25 May 2018 3:38PM
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Bara said..

jbshack said..


Bara said..
Yes I was surprised by the rpela complete fail too. I thought it would just be reduced effectiveness like the shark shield. Different frequency different current though.

Trials were in series ie one board in the water at a time.

60% effective for just 15 minutes should have been the headline. Or 100% inneffective after 30 mins?Hardly compelling stuff and certainly not a viable "solution"




I would suggest that testing 5 products continually, one after an another, on only a hand full of sharks, whilst competing with cage divers that have 8 people in the water, and other testing going on im not surprised at their results. It would be interesting if they had showed the order in which products were tested and if the results wound down over time..

Its as i would have figured with the SS being a most powerful unit, but in reality their is still the small matter of being able to use the product comfortably with out the unit being turned of, or having to apply stickers to reduce the power. The simple fact that the SS stopped an interaction 40% of the time under those conditions is actually very good. I guess its a case of power vs comfort of use = product.

Dave was present for all the testing and has since leaving those completed more "real world" testing locally of Esperance and those details he will release once completed.

But yes Bara i completely agree with your comment about being sick of the politics of sharks..

For me still, very happy paddling with my Rpela..

I would suggest anyone who has any issues/questions to contact Dave directly..



Lol i think one thing we can draw from the study though is that if dave had jumped in the water with his repela for the ultimate proof of confidence there is a 97% chance he wouldnt be with us now!

not sure how you can have any confidence in the rpela after this study.


I can be confident because i have done My research, i understand exactly how the testing went down, what happened and in what order. I have spoken with two people who were their for all the testing, have you?

jbshack
WA, 6913 posts
25 May 2018 3:45PM
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Ctngoodvibes said..
Report seems to indicate the lower frequency of SS compared to rpela could be the reason for the difference in performance - Dave if your reading - do you have any plans to adjust the frequency?


What did happen was that Dave did play around with different fields and electrodes. (It mentions that in the report) He tried to push out the distance to turn the shark earlier and found it not as good as his original. That hurt some results but what i find curious is that the SS had nearly two and half time the interactions than other products. SO thats two and half more time sharks approached the board. The results mentions that if more interactions had happened for the the other products results could have been different.

MDSXR6T
WA, 1019 posts
25 May 2018 5:23PM
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jbshack said.
I can be confident because i have done My research, i understand exactly how the testing went down, what happened and in what order. I have spoken with two people who were their for all the testing, have you?


When and where did you do YOUR research? How many different white sharks did you test on and under what conditions (tides, moon phases, cloud cover, baits used etc) did you test the units? Are you willing to share your findings?

I heard reports that someone was seen dangling a live 20kg sambo off Esperance in close vicinity of a big white so maybe someone else understands the difference between a ****house "lure" and a live bait

Legion
WA, 2222 posts
25 May 2018 6:14PM
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bjshack said..
It would be interesting if they had showed the order in which products were tested and if the results wound down over time..


Read the Science. They concluded there was no habituation. Search for the word "temporal". They are quite clear on that.

Legion
WA, 2222 posts
25 May 2018 6:19PM
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bjshack said..
The results mentions that if more interactions had happened for the the other products results could have been different.


Correct. They mention that if they increased the number of trials they might be able to detect increases less than 15% better than a placebo. Woohoo.

Legion
WA, 2222 posts
25 May 2018 6:21PM
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bjshack said..
I have spoken with two people who were their for all the testing, have you?


Ooh, ooh, I have! Do I get a medal?

TimKay
752 posts
25 May 2018 6:40PM
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No matter how people want to selective read the report and look at the findings through rose coloured glasses.
For the average surfer on the street that wants to buy a device that may decrease the chance of an attack there are quite a few that they would scratch off the list to purchase
Rpela included.
I definitely respect what they are trying to do. Be apart of the solution and to make surfing safer but it's pretty obvious that they are not there yet.
Give them time.
Probably the effective bit of equipment would be the tourniquet leggy to give you a fighting chance in the unlikely event of getting bit
And we also try and make the best judgement every time we paddle out.

TimKay
752 posts
26 May 2018 6:45AM
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To me the report would of have a success to whatever device if the shark avoided it time and time again.
Clearly this did not happen
As Kerry Packer says "Don't get bitter, get better"

IFocus
WA, 582 posts
26 May 2018 10:51AM
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TimKay said..
To me the report would of have a success to whatever device if the shark avoided it time and time again.
Clearly this did not happen
As Kerry Packer says "Don't get bitter, get better"


I agree about the get better

Personally I am going to avoid going surfing in a burley slick next to two shark cage diving operations with a slab of tuna strapped to me



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"Shark attack at Cobblestones , Gracetown" started by esoom