Hi folks,

I just relaunched my boat after painting the bottom, installing new
zincs and instruments. That was in March of this year. Around the 1st
of July, I scrubbed the bottom in preparation for a race, and noticed
the zinc on the strut was nearly gone, despite only having been in the
water 3 months. Someone tells me this is because I need an isolator.
What is an isolator, and how does it work? Big picture and simple
answers preferred.

thanks,

Luc

luc wrote:
Hi folks,

I just relaunched my boat after painting the bottom, installing new
zincs and instruments. That was in March of this year. Around the 1st
of July, I scrubbed the bottom in preparation for a race, and noticed
the zinc on the strut was nearly gone, despite only having been in the
water 3 months. Someone tells me this is because I need an isolator.
What is an isolator, and how does it work? Big picture and simple
answers preferred.

thanks,

Luc

The galvanic isolator goes in your AC ground line (the green wire) and
prevents your zinc, which is presumably connected to your boat's AC
ground wire via the boat grounding systems, from trying to protect your
neighbors' boats, the dock and any other immersed water in the vicinity.

The shore power green wire goes to the isolator as it's first connection
in the boat.

Alternatively, disconnect your shore power.

bob

RW Salnick wrote:
luc wrote:
Hi folks,

I just relaunched my boat after painting the bottom, installing new
zincs and instruments. That was in March of this year. Around the 1st
of July, I scrubbed the bottom in preparation for a race, and noticed
the zinc on the strut was nearly gone, despite only having been in the
water 3 months. Someone tells me this is because I need an isolator.
What is an isolator, and how does it work? Big picture and simple
answers preferred.
thanks,

Luc

The galvanic isolator goes in your AC ground line (the green wire) and
prevents your zinc, which is presumably connected to your boat's AC
ground wire via the boat grounding systems, from trying to protect your
neighbors' boats, the dock and any other immersed water in the vicinity.

The shore power green wire goes to the isolator as it's first connection
in the boat.

Alternatively, disconnect your shore power.

bob

Bob is correct, but keep in mind that
other causes could be responsible for
the rapid zinc depletion. They're much
less common, however.

If you hire a competent marine
electrician, he can quickly verify that
the problem would be fixed by installing
a galvanic isolator.

Chuck

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"luc" wrote in news:1153249242.027049.36020
@i42g2000cwa.googlegroups.com:

Hi folks,

I just relaunched my boat after painting the bottom, installing new
zincs and instruments. That was in March of this year. Around the 1st
of July, I scrubbed the bottom in preparation for a race, and noticed
the zinc on the strut was nearly gone, despite only having been in the
water 3 months. Someone tells me this is because I need an isolator.
What is an isolator, and how does it work? Big picture and simple
answers preferred.

thanks,

Luc



http://www.yandina.com/electrolysis.htm
http://www.jefa.com/install/electro.htm
http://marinesurvey.com/yacht/corrosion_1.htm
http://www.sailnet.com/collections/a...eid=hughes0004
http://www.protroll.com/blkbox3.html

By far the majority of accelerated zinc loss cause is the shore power
connection.
The first step is to install a galvanic isolator.
Defender has them on sale for about $95 at
http://www.defender.com/product.jsp?path=-1|328|303336&id=605562


Regards,

Ann-Marie Foster,

My boat also goes through zincs in 100 days +/-. I have a GI installed. How
can I tell if my boat is the problem or if it's neighbors or the marina
(without disconnecting from shore power for 90 days :-) )?

Mike


"Andina Marie" wrote in message
oups.com...
By far the majority of accelerated zinc loss cause is the shore power
connection.
The first step is to install a galvanic isolator.
Defender has them on sale for about $95 at
http://www.defender.com/product.jsp?path=-1|328|303336&id=605562


Regards,

Ann-Marie Foster,

Mike wrote:
My boat also goes through zincs in 100 days +/-. I have a GI installed. How
can I tell if my boat is the problem or if it's neighbors or the marina
(without disconnecting from shore power for 90 days :-) )?

Mike


Hello Mike,

First thing is buy a copy of "The 12
Volt Doctor's Practical Handbook" at
your local marine store.

With a simple DMM you can do some
testing to answer your question. You can
even test neighboring boats if you can
clamp a test lead onto a shroud or
grounded piece of metal. Some folks will
have strong feelings about this
"trespassing" but you need not board the
vessel and will not mar it or subject it
to damage in any way by the testing. If
you know the owner, you may even find
him willing to participate.

Anyway, you need to disconnect the shore
power only for the duration of the test,
which should be less than 5 minutes.

Read the (very short) book and post any
questions you have.

Having said all that, I must say that
100 days is too short a period for zinc
life. There are many possibilities,
starting with whether your zincs are too
small. Did you notice a difference in
zinc life when you installed the GI? Can
you triple the zinc size easily? Have
you considered a supplemental zinc
hanging over the side? Good to have one
on board anyway.

Good luck.

Chuck

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"Mike" wrote in news:b8idnTRka-tz-
:

(without disconnecting from shore power for 90 days :-) )?



Install an isolation transformer with an ISOLATED GROUND. That allows the
AC to flow across the transformer windings but not the galvanic current,
which is DC.....unless some idiot hooks you boat ground to the dock ground
rendering the isolation useless.



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I understand how NO ground connection is better than a typical setup with an
isolator, but if the isolator is functioning, isn't the effect very close to
the same?

Let me ask it another way. If I have about 0.2 VDC across the galvanic
isolator, would I see about the same between the shore ground and
neutral/ground on the boat side of an isolation transformer?

"Larry" wrote in message
...
"Mike" wrote in news:b8idnTRka-tz-
:

(without disconnecting from shore power for 90 days :-) )?



Install an isolation transformer with an ISOLATED GROUND. That allows the
AC to flow across the transformer windings but not the galvanic current,
which is DC.....unless some idiot hooks you boat ground to the dock ground
rendering the isolation useless.

On 19 Jul 2006 05:51:08 -0700, "Andina Marie"
wrote:

By far the majority of accelerated zinc loss cause is the shore power
connection.
The first step is to install a galvanic isolator.
Defender has them on sale for about $95 at
http://www.defender.com/product.jsp?path=-1|328|303336&id=605562

=================

Is it possible to install the isolator external to the boat using the
right combination of connectors and junction boxes?

The shore power circuits on my boat are almost impossible to get at in
any reasonable way.