On Tue, 19 Jan 2010 07:55:55 -0700, "Noj Zang"
wrote:


"Bruce In Bangkok" wrote in message
.. .

It is not electrolysis I'm fighting, it is shellfish.


Let's try again. The link says:

The application of pulsed electric fields to water containing micro- or
macro-organisms has been proven to be a means of controlling the population
of these organism, or to stun them over a certain electric field dependent
time interval. The fact that the efficiency of this control mechanism
increases with decreasing pulse duration opens the possibility to utilize
microsecond pulse power technology for biofouling prevention in cooling
water systems. The advantages over other techniques used for biofouling
prevention such as its independence from chemicals, the fact that it is
possible to stun, rather than kill unwanted biofouling species, that it does
not generate shock waves which could affect the structure of the cooling
system, and that it can be installed like a filter in front of an existing
cooling system, without requiring any changes in the cooling system, make
the pulsed electric field technology (PEFT) a strong contender to existing
biofouling prevention methods. A recent field study, where tidal water from
the Elizabeth River in Norfolk, VA, was treated by means of the pulsed
electric field method, demonstrated complete prevention of biofouling in
pipes when the river water at the intake of the pipes was exposed to
electric field of 6.5 kV/cm with 770 nanosecond pulse duration. The
efficiency was 1,400 gallons of treated water per kWh, an increase in
efficiency by more than a factor of three compared to results presented at
the 1996 Zebra Mussel Conference. Experiments with even lower electric
fields and correspondingly lower energy consumption are under way. modeling
results indicate that efficiencies of more than 50,00 gallons/ kWh may be
reached in fresh water cooling systems.

The livestock fence shocker delivers said pulsed electric field of required
intensity. If the electric pulse is monophasic it delivers net charge into
the water, creating electrolysis. If the electric pulse is biphasic (ie:
capacitively coupled) it will deliver no net charge into the water, avoiding
electrolysis.

I, know, I know. It's not livestock that are giving your propellor problems
and the article only mentions zebra mussels in 1996.

But then you are the guy who wrapped electrical connections in tape for
frequently flooded aircraft runways and buried them in the ground, despite
the law saying those connections should be above ground in a hermetic box.
How many died because of that?

I suggest that you query the U.S. Air force about regulations applying
to the installation and maintenance of air field lighting systems on
US Military Installations as all work was carried out in accordance
with their specifications. I might also point out that the USAF
maintains a force of inspectors who daily inspect the work
accomplished by contractors so I can only assume that the taped
splices were acceptable to Air Force.

With barnacle growth the size of a medium shopping trolley fouling your
drive train at least you have the electrolysis problem solved as there are
no exposed metals to electrolyze.

I have studied this in depth at university in Bangalore.



Noj


Regarding the electronic barnacle deterrent. Yes, I've seen the web
site on the Internet but what I haven't seen is a yacht with the
system installed. In fact I have never even met an individual who was
thinking about installing the system.

Now, given that every boater who keeps his boat in the water is
interested in shellfish growing/not growing on his hull it pretty much
tells me that either the system doesn't work, or that the system is
not cost effective.

Care to give me a list of boat owners who I can contact to ask them
what they think of the system?

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)