GL: More On The Illinois Electric Fish Barrier

[Ron Rogers]

There you go again, clouding the issue with facts and intelligent questions!
When will you ever learn?

Ron Rogers

-----Original Message-----
From: Ken Bloomfield

What I would like to see is the data that indicates the potential for 
danger to boats.  I realize that the voltage stress impressed in the 
water has been raised from 1 volt per inch to 4 volts per inch, but for 
the life of me I could not find out an number of key facts that would 
help me understand the real issue.  These are:

1.  What is the maximum voltage used?  To achieve the 4 volts per inch 
that I have hear about, you need some voltage difference between a pair 
of electrodes.  The further apart these electrodes are, the more the 
voltage that is needed, and that would (I assume) dictate the maximum 
voltage employed.

2.  Is this voltage high enough to cause sparks between two pieces of 
metal, and if so, how close do they have to be.

3.  What is the real danger?  If it is falling overboard, and the water 
is electrified, then I would guess that if you then grabbed a steel boat 
that you would likely be in more danger than if you grabbed a fiberglass 
boat.  Is it that there is a suspicion that there will be a potential 
difference of some significant voltage between a pair of metal throughhulls?

4.  I would expect that to achieve a 4 volt per meter electrical 
gradient in the water that rather than use a widely spaced pair of 
electrodes with a very high voltage that you would use multiple pairs of 
electrodes spaced fairly close together and use a much lower voltage.

5.  The pictures that I have seen indicate the electrodes are lying on 
the river bottom.  Has anyone actually measured the voltage gradient 
near the surface?  I would guess that it varies from very strong (in 
volts/meter) near the electrodes to progressively less as the distance 
from the electrodes.

6.  Certainly a good dose of caution is warranted, but there seems to 
have been a prototype barrier that has been working and folks have been 
passing it fine for some time.  Was there no testing carried out on a 
non-disruptive track of water prior to closing off a navigational route?

7.  If the prototype barrier was not 100% effective, then is this kind 
of like closing the barn door after the horses have escaped?

Sure wish there was more detailed info available.  I found the site that 
listed the meetings (and minutes thereof) of some of the committee 
dealing with this, and frankly it was not very informative.