TWL: Saxton Bill in action tomorrow, Wed.
Has anyone ever experimented with sacrificial anodes made of materials more
noble than zinc?
We've got a wood boat that gave us an extravagantly expensive lession in
electrolysis when we first got it, and now I know that zinc drives voltage
potentials too high for the good of the wood (>1000 millivolts, where it
should be >500 and <700). I've got two kinds of metal that see salt water
on my boat, silicon bronze (struts, shaft logs, rudders, through-hulls,
fasteners), and monel (the prop and rudder shafts). Actually, to be totally
honest, I don't know what bronze alloy the prop is made from. And I'm sure
there's some stainless in the odd fastener here and there.
I've just noticed, for example, that there's a class of aluminum anode.
Aluminum would drive the voltage potential to around 600-700mv, which would
be perfect for the bronze. Bringing the numbers down would make the anode
less hot, draw less current and make the anodes last longer, it would seem
to me. And aluminum is ignoble enough that it probably wouldn't lead to
terrible side-effects in leaching midnobles out of the prop alloy, but
here's were I'm edging onto thin ice.
Apparently, there's no mil-spec designation, but there is something called
the B605 alloy specification, the origins of which are a mystery to me
(having only heard of it since yesterday).
The other alternative is an electrical controller. But knowing that the
wrong move could fry everything in a matter of days, I'd be happy to find a
more natural solution, so I'd like to keep that topic out of this thread, at
least for the time being.
My zincs have been drawing 1000mv through my bronze for a year since the
boat's been in the water. I'm a year more educated, and the sealant around
the struts and shaft logs in the new planks is a year closer to getting
wet. I'm supposed to be getting new zincs this week, and so now's the time
to start getting this right.
Am I playing with fire or putting out the fire?
Doug Hoople
M/V Bomar
1963 Stephens Bros. 50 FDMY
Sausalito, CA
Steve,
I'm looking for a 'cooler' anode, not a 'hotter' anode.
I've discovered that there's a class of aluminum zincs that are 'hotter' or
'more active' than zinc. These aren't really aluminum, but alloys mixed heavily
with less noble metals even than zinc. And your Mooranode looks like such a
beast. Calling them aluminum is misleading, if potentially technically correct.
This doesn't address my problem. My zincs took a year to go, which I'm guessing
is pretty good. My boat has an isolation transformer, original equipment with
the boat, and it works great. I don't have stray current or shared ground
problems. And my noble metals aren't deteriorating at all. I'm just trying to
keep my wood from rotting and having our boat in the yard for lots of money
again in 5-10 years, which is the way so many wood boats go.
The 'hotter-than-zinc' anode would only make my problem worse, because a
more-active metal would drive the voltage up further still, and I'm trying to
bring it down. Zincs bring the natural voltage potential up to +1000mv, and I'm
trying to keep it under 700mv without resorting to active electrical
controllers.
Again, a proper marine aluminum anode that drives the potential to 600-700mv
would be just the thing. Or any anode that accomplished that, whatever the
metal. Bet they don't make it. There just aren't enough of us woodies, and
there aren't any other folks out there who'd need it.
BTW, Steve, your electrics sound really hot. I'd look at fixing the problem by
installing galvanic isolators or an isolation transformer and doing a
comprehensive check for stray current on board. The Mooranode seems to be just
hiding the real problem.
Doug Hoople
M/V Bomar
1963 Stephens Bros. 50 FDMY
Sausalito, CA
Steven Dubnoff wrote:
At 07:22 AM 4/30/2002 +0100, you wrote:
Has anyone ever experimented with sacrificial anodes made of materials more
noble than zinc?
I have been using a little (perhaps un-) known product known as the
Mooranode.
You drop it in the water in your slip and connect it, one way or another,
to your vessel's DC ground. The theory is that the aluminum anode will go
before your zincs.
Got this from another group. Please support this bill by writing your
rep. and/or the chairman of the committee, John Duncan. You can find
your rep. at: http://www.house.gov/writerep/
Hello List,
It is time to act now. In two days, Wednesday, a bill will be on the
hearing committee table that will affect our future for decades. Please
help strike the iron while the fire is hot!
Below is a letter sent to the Chairman of the House Committee. Use what
you will but please try to fax or contact your representative today.
Schedule 107th Congress 2nd Session
Reference: MAY: May 1
Subcommittee on Water Resources and Environment
Hearing on H.R. 3673, the "Recreational Waters Protection Act"
10:00 a.m.
2167 Rayburn House Office Building
Committee on Transportation and Infrastructure
Water Resources & Environment
Rep. John Duncan (R-TN), Chairman
U.S. House of Representatives, B-376 RHOB (Rayburn House Office Bldg.),
Washington, DC 20515
Tel- 202-225-4360
Fax-202-225-6440
http://www.house.gov/transportation/water
CONTACT INFORMATION: http://www.house.gov/duncan/2002/contactme.htm
Honorable John Duncan,
I realize your support is vital to the future of this bill. This past
Saturday, the Boater Voter Coalition had an opportunity to meet with
Congressman Rob Andrews. After listening to this issue, he promised
support for the bill. As Chairman of the Boater Voter Coalition,
representing Thousands of Boaters in New Jersey and Associated with
numerous organizations representing recreational and environmental
concerns in the North Eastern area of our great country, I urge your
support of the above reference bill H.R.3673 providing new standards for
recreational boaters release of treated material.
This NEW STANDARD is the first improvement in over twenty years,
establishing a higher quality of release from Type 1 marine sanitation
devices, which is 100 times more stringent than current standards. More
over, the released material of the New Devices is cleaner from the
bacteria, viruses, nutrients and harmful chemicals currently found in
municipal effluents after treatment from collected pumpout stations.
The quality of the release of these NEW devices under HR 3673 is 20
(TWENTY) TIMES cleaner than most states require for bathing and nearly
30% more pure than Federal Law requires for waters where shellfish are
harvested for human consumption.
Existing No Discharge Zone (NDZ) approach does not work to the benefit
of the environment. It is highly unlikely that law enforcement efforts
will ever be sufficient to make the NDZ work. Numerous situations such
as hours of operation of pumpout locations, distance to locations,
climatic zones or storm conditions force the closing of locations. At
times, the pumpout locations are either in a state of disrepair or
containment tanks are full and unable to accept additional material.
This new opportunity in science and product gives boat owners improved
operation of their vessels and at the same time contribute to improving
the aquatic environment with today's technology.
I encourage you to join our group in support of this important piece of
conservation legislation. It is logical, good science and a new step
forward. Should you have any questions contact Rep. Jim Saxton or
Jennifer Drazek on his staff at 202-225-4165 or the Boater Voter
Coalition at 609-877-2561 (email the BVC - SECURITY@FCC.NET)
Sincerely,
Jerry Donofrio Sr.
Chairman
--
Jerry Donofrio Sr.
Chairman
11 Needlepoint Lane
Willingboro, NJ 08046
Tel 609-877-2561 voice mail box #3
Visit our Boater Voter Coalition Web Page !!!!
Information on Boating in New Jersey and PA.
Join The BVC web site click here for it
http://sport.nj.com/sport/boatervoter
Keith
God doesn't play dice. -- Albert Einstein
Doug Hoople wrote:
My zincs have been drawing 1000mv through my bronze for a year since the
boat's been in the water.
Sorry Arild,
Poor choice of words 'drawing 1000mv'. What I meant is that the zinc will drive the potential to its
natural galvanic level, which as compared to the silver/silver-chloride half cell, is over 1000mv. The
galvanic effect will cause whatever current is necessary to flow to drive the voltage to that level.
At least we're agreed that the voltage level is one indicator of whether electrolysis will occur, and
that in this regard +1000mv is bad, and 400-700mv is OK (for mahogany and bronze, at least).
I'm not a fan of electrical controllers, as they often cause more harm than good. A wood boat's
electrical system is an ecosystem that requires balance, and that balance is achievable organically, if
you will. I liken the electrical controllers to the use of chemical pesticides and herbicides in
farming. They create unintended side-effects, and cause more harm than good unless understood at an
extraordinarily nuanced level.
I suspect that the use of zinc as a universal anode stems from two causes, 1) it's so ignoble that
it's safe to use without worrying about the martyrdom of other more important metals, and 2) it's the
lowest common denominator (frp, steel, aluminum, wood) and the overall market's too big to worry about
the fact that zinc is less than ideal for one of its segments. Zinc is so effective for so much of the
market, that the wood boat folks are just out of luck. Finally, it normally takes so long for
electrolysis to rear its head, that the psychological connection between the anode and the wood
deterioration is very weak.
You can cover cause number 1) above just by knowing the metals you have under the water line, but you
can't do anything about number 2) above, and the fact that it takes so long for electrolysis to appear
augurs poorly for a groundswell of popular will to change things.
I'm on track to try an experiment. I'm betting that by using an anode made of an aluminum alloy that
is rated at 600-700 millivolts relative to the silver/silver-chloride half-cell, I'll eliminate
electrolysis, and slow the rate of anode replacement.
It'll be years before I can report conclusively, but we've got time, haven't we?
Doug Hoople
M/V Bomar
1963 Stephens Bros. 50 FDMY
Sausalito, CA
Doug Hoople wrote:
My zincs have been drawing 1000mv through my bronze for a year since the
boat's been in the water.
REPLY
I would like to correct a slight mis-conception which is probably shared by many folks.
Voltage is a measure of electrical pressure, not a measure of flow which is measured in amps or
milliamps.
If you measure a voltage of 1000 mv. where is this measured?
Are the fittings bonded or not bonded?
If the fittings are bonded and the voltage is measured on the bonding wire relative to a silver-
silver chloride cell; then such a high voltage is an indication of too large a zinc.
A simple analogy is to think of the zinc as a small battery charger and the metals to be
protected as a discharged battery.
When the charger can not supply enough to fill the battery, the voltage is low.
If the charger can supply more current than the battery can absorb, the voltage is high.
Electro Guard makes a system which consist of a variable resistor in series with the zinc and
the bonding wires. The millivolt meter on the panel measures the voltage on the bonding wire.
You adjust the variable resistor to yield a voltage on the bonding wire of approximattely 400 - 600
mv. At that point the metals are protected.
If the bonding wire and connected metal fittings measure a higher voltage, then the zinc is too
much in relation to the mass of metal to be protected. You are over protected.
If the voltage is too low < 400 mv then you do not have sufficient zinc to provide adequate
protection.
The variable resistor limits the current flow until the voltage indicates a balanced state.
Any stray leakage current from either the AC or DC wiring can skew this reading.
This is in fact used as a method of detect if a wiring problem occurs.
Wood electrolysis occurs when you have too much zinc and thus are over protected.
Sodium Hydroxyl crystals form on the wood and metal fastners which see excess current
flowing from zinc to metal fitting.
I highly recommend a book titled
The Boatowner's Guide to Corrosion, by Everett Collier, published by McGraw Hill
ISBN 0-07-155019-4
Written in layman's language; it deals with all manner of corrosion, not just stray current or
galvanic types. Has a detailed description of alloys and ASTM numbers.
Hope this helps.
Arild
Steve wrote
After a disastrous lesson in the dangers of electrolysis, in which I lost a
prop in a month or two, I have been using a little (perhaps un-) known
product known as the Mooranode.
You drop it in the water in your slip and connect it, one way or another,
to your vessel's DC ground. The theory is that the aluminum anode will go
before your zincs.
REPLY
I suspect the alloy is magnesium not aluminum.
Aluminum is more noble than zinc but not by much.
In fresh water the voltage difference is slight so magnesium is used instead of zinc to protect
aluminum alloy outdrives etc.
Since the Mooranode is being consumed before the zinc, it has to be more active in the galvanic
series. Magnesium is one of the few that fits the description.
regards
Arild
Doug Hoople wrote:
I'm not a fan of electrical controllers, as they often cause more harm than good. A wood boat's
electrical system is an ecosystem that requires balance, and that balance is achievable organically,
if you will. I liken the electrical controllers to the use of chemical pesticides and herbicides in
farming. They create unintended side-effects, and cause more harm than good unless understood at an
extraordinarily nuanced level.
REPLY
I'm inclined to agree, based on my own observations in the field.
However, I would like to clarify one thing. There are two kinds of "electrical" controller systems.
The active kind that "impresses" a counter voltage onto the bonded fittings.
This is the one that is really prone to causing damage if a malfunction occcurs.
The other kind is "passive" in that it does not actively control the amount of protection current
flowing from the zinc to the under water fittings.
It consist of a resistor placed in series between the zinc and the bonding wire connecting the
fittigns to be protected.
A millivolt meter is permanently connected to read the voltage on the bonding wire referenced to
a cell ( usually silver - silverchloride )
One company - ElectroGuard - uses a zinc instead of a silver silverchloride cell but that is
another story.
By monitoring the voltage, you can adjust the resistor to give you exactly the right voltage to
neutralize the galvanic potential created by the dis-similar metals in the water.
This is perhaps more convenient that having to place the silve cell over the side and having to
connect your test meter to each fitting or the bonding wire.
With a passive system, the only risk of failure is if the bonding wire breaks, corrodes or the
meter itself fails, or the zinc completely erodes away. Presumably, periodic inspections as a
normal part of boat maintenance would reveal these deficiencies long before a catastrophic
failure occurs.
The passive system is litttle more than a permanently installed test meter and a means of
adjusting the zinc size to suit your boats under water fittings.
It has the additional advantage of making convenient, frequent, inspections possible.
regards
Arild
At 07:22 AM 4/30/2002 +0100, you wrote:
Has anyone ever experimented with sacrificial anodes made of materials more
noble than zinc?
After a disastrous lesson in the dangers of electrolyses, in which I lost a
prop in a month or two, I have been using a little (perhaps un-) known
product known as the Mooranode. This consists of a several pound chunk of
an aluminum alloy that is apparently used in the offshore oil industry to
protect their rigs. This is attached to a piece of wire and a heavy duty
alligator clip.
You drop it in the water in your slip and connect it, one way or another,
to your vessel's DC ground. The theory is that the aluminum anode will go
before your zincs.
I still consume zincs, but at a slower rate, and there is a noticeable loss
of material off of the Mooranode. (I ground mine through the shrouds -- I
think if I had a better ground it might work even better).
This product is horribly marketed (see www.mooranode.com). I only found
out about it because my contractor is an ex-neighbor of its inventor and
uses it on his boat.
Given the costs of sending a diver down to change your zincs every three
months, I think it is good insurance.
Best,
Steve
Steve Dubnoff
Nauticat 40 M/S, Pyxis, in Washington
sdubnoff@circlesys.com
We have the Electro-Guard system on Ancora. The vessel has only the two
large plate zincs on the transom, none on the underwater gear. With
Electro-Guard the plate zincs last a lot longer than without, and I can
monitor the underwater conditions and adjust accordingly. Usual disclaimers.
----- Original Message -----
From: "Arild Jensen" elnav@uniserve.com
To: "trawlerworld list" trawler-world-list@samurai.com
Sent: Friday, May 03, 2002 5:32 AM
Subject: Re: TWL: Zinc protection
Doug Hoople wrote:
I'm not a fan of electrical controllers, as they often cause more harm
than good. A wood boat's
electrical system is an ecosystem that requires balance, and that
balance is achievable organically,
if you will. I liken the electrical controllers to the use of chemical
pesticides and herbicides in
farming. They create unintended side-effects, and cause more harm than
good unless understood at an
extraordinarily nuanced level.
REPLY
I'm inclined to agree, based on my own observations in the field.
However, I would like to clarify one thing. There are two kinds of
"electrical" controller systems.
The active kind that "impresses" a counter voltage onto the bonded
fittings.
This is the one that is really prone to causing damage if a malfunction
occcurs.
The other kind is "passive" in that it does not actively control the
amount of protection current
flowing from the zinc to the under water fittings.
It consist of a resistor placed in series between the zinc and the
bonding wire connecting the
fittigns to be protected.
A millivolt meter is permanently connected to read the voltage on the
bonding wire referenced to
a cell ( usually silver - silverchloride )
One company - ElectroGuard - uses a zinc instead of a silver
silverchloride cell but that is
another story.
By monitoring the voltage, you can adjust the resistor to give you exactly
the right voltage to
neutralize the galvanic potential created by the dis-similar metals in
the water.
This is perhaps more convenient that having to place the silve cell over
the side and having to
connect your test meter to each fitting or the bonding wire.
With a passive system, the only risk of failure is if the bonding wire
breaks, corrodes or the
meter itself fails, or the zinc completely erodes away. Presumably,
periodic inspections as a
normal part of boat maintenance would reveal these deficiencies long
before a catastrophic
failure occurs.
The passive system is litttle more than a permanently installed test meter
and a means of
adjusting the zinc size to suit your boats under water fittings.
It has the additional advantage of making convenient, frequent,
inspections possible.
regards
Arild
Does anyone know how the hearing went?
-----Original Message-----
From: owner-trawler-world-list@samurai.com
[mailto:owner-trawler-world-list@samurai.com]On Behalf Of Keith
Sent: Tuesday, April 30, 2002 5:51 AM
To: trawlerworld list
Subject: TWL: Saxton Bill in action tomorrow, Wed.
Got this from another group. Please support this bill by writing your
rep. and/or the chairman of the committee, John Duncan. You can find
your rep. at: http://www.house.gov/writerep/
Hello List,
It is time to act now. In two days, Wednesday, a bill will be on the
hearing committee table that will affect our future for decades. Please
help strike the iron while the fire is hot!
Below is a letter sent to the Chairman of the House Committee. Use what
you will but please try to fax or contact your representative today.
Schedule 107th Congress 2nd Session
Reference: MAY: May 1
Subcommittee on Water Resources and Environment
Hearing on H.R. 3673, the "Recreational Waters Protection Act"
10:00 a.m.
2167 Rayburn House Office Building
Committee on Transportation and Infrastructure
Water Resources & Environment
Rep. John Duncan (R-TN), Chairman
U.S. House of Representatives, B-376 RHOB (Rayburn House Office Bldg.),
Washington, DC 20515
Tel- 202-225-4360
Fax-202-225-6440
http://www.house.gov/transportation/water
CONTACT INFORMATION: http://www.house.gov/duncan/2002/contactme.htm
Honorable John Duncan,
I realize your support is vital to the future of this bill. This past
Saturday, the Boater Voter Coalition had an opportunity to meet with
Congressman Rob Andrews. After listening to this issue, he promised
support for the bill. As Chairman of the Boater Voter Coalition,
representing Thousands of Boaters in New Jersey and Associated with
numerous organizations representing recreational and environmental
concerns in the North Eastern area of our great country, I urge your
support of the above reference bill H.R.3673 providing new standards for
recreational boaters release of treated material.
This NEW STANDARD is the first improvement in over twenty years,
establishing a higher quality of release from Type 1 marine sanitation
devices, which is 100 times more stringent than current standards. More
over, the released material of the New Devices is cleaner from the
bacteria, viruses, nutrients and harmful chemicals currently found in
municipal effluents after treatment from collected pumpout stations.
The quality of the release of these NEW devices under HR 3673 is 20
(TWENTY) TIMES cleaner than most states require for bathing and nearly
30% more pure than Federal Law requires for waters where shellfish are
harvested for human consumption.
Existing No Discharge Zone (NDZ) approach does not work to the benefit
of the environment. It is highly unlikely that law enforcement efforts
will ever be sufficient to make the NDZ work. Numerous situations such
as hours of operation of pumpout locations, distance to locations,
climatic zones or storm conditions force the closing of locations. At
times, the pumpout locations are either in a state of disrepair or
containment tanks are full and unable to accept additional material.
This new opportunity in science and product gives boat owners improved
operation of their vessels and at the same time contribute to improving
the aquatic environment with today's technology.
I encourage you to join our group in support of this important piece of
conservation legislation. It is logical, good science and a new step
forward. Should you have any questions contact Rep. Jim Saxton or
Jennifer Drazek on his staff at 202-225-4165 or the Boater Voter
Coalition at 609-877-2561 (email the BVC - SECURITY@FCC.NET)
Sincerely,
Jerry Donofrio Sr.
Chairman
--
Jerry Donofrio Sr.
Chairman
11 Needlepoint Lane
Willingboro, NJ 08046
Tel 609-877-2561 voice mail box #3
Visit our Boater Voter Coalition Web Page !!!!
Information on Boating in New Jersey and PA.
Join The BVC web site click here for it
http://sport.nj.com/sport/boatervoter
Keith
God doesn't play dice. -- Albert Einstein