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How To Prevent Corrosion – Permanently

How to prevent corrosion, training.

I ask you to spend two minutes and so avoid a 1% risk of loss of your vessel.  Read up to “For the curious”.

We will guide you step by step to prevent All the CAUSE/S of corrosion. Permanently.

No electrical knowledge required. Even if you do not know what a fuse is, as part of your purchase of SeaBis Master, we will step you through How to Prevent Corrosion.  Preventing the CAUSE of corrosion, permanently.


Understand the cause:

1: Stray electrical current is the actual energy that dissolves your metal. SeaBis Master measures and indicates current as current. To an accuracy of 10 parts in a millionth of an amp.

2: Voltage is not energy. It is the POTENTIAL, subject to many other factors, to vary the current. Voltage can be measured cheaply. Without knowing ALL the other factors, measuring voltage is valueless. Corrosion will escalate:

3: “I never had corrosion this bad before”. Explanation: as the metal surface roughens, so its area increases. As the area increases, stray current increases …

Stray current is directly affected, linearly, by the speed of water past the metal. So, propellers attract and conduct stray current far worse than most static metal.

The remainder is not necessary to complete prevention of the CAUSE of marine corrosion.

Contact us, and as part of your purchase of SeaBis Master, we will step you or another through corrosion CAUSE prevention.  100% effective. Permanently. 

For the curious.  Vast knowledge based on factual methodical verified experience: 

There follows in depth knowledge based on more than 2,000 vessels where All CAUSES have been 100% prevented. Permanently. Successfully.

To progress in life, we need to learn.  It took me a lifetime to understand how to prevent corrosion, permanently. The proof are testimonials and 8 years guarantee (physical properties) AND Warranty (functional properties) – in writing.  Photographs at Just selling SeaBis Master System is not good enough for us.  We want you to succeed.  New causes will occur. Therefore, we offer 8 years free support.

Designer Glen Bishop
Dedicated to preventing the ONLY cause of electrolysis corrosion, via air or water. Permanently.
Designer of the SeaBis System. Glen Bishop.
Glen Ray Bishop is CEO of SeaBis. He did the research and development and is responsible for manufacture and marketing SeaBis, World-wide. Surveyor to all Class Societies, World-wide. This website and his company are registered in Australia, so must comply with Australian Laws. Those laws are strict. 

Verification: Australian Business Number 27008191848. 

If in any difficulty please contact me, Glen Bishop

Diagram Explanation of Why SeaBis System is 100% Successful:

How to Prevent Corrosion.

Permanently with SeaBis Master System. 8 years written guarantee and warranty. Free support for 8 years as new causes will occur.

Link to Home page.

How to Prevent Corrosion, Detail:

Table of Contents

Stray current effects and the ONLY CAUSE:

Stray current is the cause of 97% of all marine corrosion. When stray current is prevented, electrolysis cannot occur.  How to Prevent Corrosion will allow coating, plating, anodes, ICCP and other methods of protection to work as designed.  Your hull, propeller, gearbox, engine and upper deck metal will not dissolve.

Stray current is powered by Direct Current (DC, as in batteries). Stray current dissolves your hull, propeller, gearbox, engine and upper deck fittings and fixtures by electrolysis.  And the metal under coatings and plating, so causing them to lift off the metal. SeaBis System prevents the cause of stray current.  Permanently. How to prevent corrosion works 100%.  No additional anodes, coating, plating or moving parts. Then the anodes, coatings and plating can work as designed.

External verification that we state is true:

Link:  Wikipedia, electrolysis.  Note the electrolysis test instrument is supplied with Direct Current (DC wires are red and black).  Batteries supply DC, only. The explanation details that specifically. 


AC (mains or shore power) cannot cause corrosion:

AC reverses current direction every 1/100 or 1/120 second.  IF it took off a particle in the first 1/100 second, when it reverses in the 2/100 second it would put it back on.

Therefore, AC (mains or shore or inverter power) cannot be the cause. Blockers are installed in shore power connection.  So, what good are they?

If there is any corrosive current in the AC, then SeaBis will flash red. SeaBis with How to Prevent Corrosion will isolate shore as the CAUSE. In more than 2,000 vessels cleared of corrosive current, I have never known the main / shore power to be a cause.


Voltage versus current – critical importance. 

How to Prevent Corrosion is easy when you understand: 

Voltage is the POTENTIAL for current to flow.
Current is the ACTUAL energy flowing.

So, measuring voltage MUST fail.  That failure WILL cost you increased corrosion in an *exponential manner. 

Using SeaBis Master to measure current, then switching off equipment until that stray current ceases, WILL identify the CAUSE.  How to Prevent Corrosion works 100%, permanently.


Exponential corrosion

I often hear, “I had no corrosion until a few weeks ago.”
Explanation: As the metal becomes rougher, so its surface area increases. That increases the current flow. Therefore, increasing corrosion, exponentially. I have witnessed a 10-day time period from no to extreme corrosion too many times. Therefore, use SeaBis Master with How to Prevent Corrosion, now and permanently.

SeaBis Master System prevents the CAUSE of marine corrosion.

SeaBis Master measures current as current to an accuracy of ten parts in one millionth amp. The System identifies the CAUSE and How to Prevent Corrosion, repairs it.


How to Prevent Corrosion, Technical explanation (easily understood).

SeaBis Master System, with How to Prevent Corrosion, permanently eliminates the CAUSE – stray current. We term such corrosion electrolysis.

Rust, stray current, electrolytic action, marina corrosion, boat corrosion and galvanic are all common terms.

Rust is simply air carried current, often vastly accelerated by stray current. All are CAUSED and / or vastly accelerated by the stray current that causes corrosion.  All can be prevented, permanently.

Stray Current or Galvanic Corrosion?

Stray current dissolves your metal. It is the ONLY cause.  It is ONLY caused by DC (battery power).  It cannot be caused by AC (mains or shore or inverter power).  Full stop. Permanently.  Proof follows.

Galvanic corrosion

It is caused by two different metals nearly touching in a conductor, such damp air or water.  The only example I know of is a stainless-steel ladder touching an aluminium hull without insulation. Galvanic is a million times slower than stray current corrosion and is nearly always caused and accelerated by stray current. Stop the stray current, and you stop at least 97% of corrosion.  Anodes, when stray current corrosion is eliminated, will stop galvanic and should last 3 to 4 years.  If they do not or are coated in a jelly or white hard substance or are dissolved far too fast not at all, then stray current is the cause.

All the following were ONLY caused by stray current generating electrolysis corrosion.  None caused by galvanic (different metals nearly touching).  All WILL be prevented by How to Prevent Corrosion, permanently.  Galvanic corrosion is easy to prevent when stray current is prevent FIRST.  We will advise you.

Stray current corrosion is caused by wiring or equipment defects onboard your vessel.  I witness stray current destroy propellers or hull or engine or upper deck fixtures and fittings in 10 days, many times every year.  It is a current flowing from your vessel to the Earth via the sea (the Earth we stand on, not mains/shore power earth).  This is where SeaBis with How to Prevent Corrosion, permanently, pays for itself, very quickly.  SeaBis System prevents the stray current CAUSE.  Therefore, saving you many thousands of dollars.

The stray current through electrolytic action, termed electrolysis, generates marine corrosion. So the original marine corrosion cause is your vessel creating stray current.  If you need additional clarification, contact us.



After SeaBis Master System:

After SeaBis. Antifouling works as designed.
After SeaBis. A year submerged. Marine electrolysis corrosion prevention identifies then prevents the stray current that is the only CAUSE. Permanently. Antifouling works as designed.
After SeaBis. No stray currents. Antifouling works as designed.
After SeaBis. Underwater view. A year submerged. Marine electrolysis corrosion prevention stops ALL stray current. Antifouling works as designed.

Our Guarantee, Warranty and diagnostic support:

The reason we provide an 8-year money-back guarantee (the equipment) and warranty (the function) with SeaBis Master is, we are 100% correct.  We supply 8 years diagnostic support as causes will reappear with new equipment, water ingress, insulation failure, carbon build up. How to Prevent Corrosion, instructions must be complied with.

Testimonials at:

Corrosion CAUSE prevented, permanently
8-year guarantee, warranty and diagnostic support, Free. Email:

Do not waste your money: 

Anodes? Can I add more to prevent corrosion?

A one kilo gram (1,000 grams) or two pound anode generates 1/(divided by)1,000,000 or one millionth of an amp protective current. Whereas stray current is 100 to at least 1,000,000 times stronger. Therefore, you would need 100 too at least 10,000 kilo grams of anode! Use SeaBis Master System with How to Prevent Corrosion to prevent the CAUSE, completely and permanently.


Multi meter, half cell, reference electrode or test lamp? 

Can any of them prevent corrosion?
Sorry but no. The consequence will be to waste your time and money while corrosion escalates. The reason is, corrosion is caused by CURRENT flow to the Earth. They all measure the COMBINED VOLTAGE of every vessel within 200 meters and that of the Earth. Not current. The result is misleading information.  Therefore, use SeaBis Master with How to Prevent Corrosion to measure current flow to the Earth and correct the cause – it works 100%. That is why we provide an 8-year guarantee and warranty.


How to Prevent Corrosion versus Blocker?

Why waste your money while corrosion escalates?

Some will try confusion by calling Blocker a Galvanic Isolator! Galvanic corrosion is ONLY caused by nearly touching different metals.  Such as a stainless steel ladder against an aluminium hull. A little respect, please.

AC or shore power cannot be the cause, so what does the Blocker achieve?

If there is any corrosive current in the AC, then SeaBis will flash red. SeaBis with How to Prevent Corrosion will isolate shore as the CAUSE. In more than 2,000 vessels cleared of corrosive current, I have never known the main / shore power to be a cause.

Don’t be deceived. AC – Mains / shore power CAN NOT be the cause. The reason:  AC is the abbreviation for alternating current.  It reverses current direction every one hundredth of a second.  Therefore, IF it removed metal in the first one hundredth second, it would replace it in the next one hundred of a second. AC cannot be the cause.  If it were, then SeaBis would flash red.  SeaBis System would identify AC as the cause.

VERIFY their claims.
Ask for their WRITTEN guarantee. Read it.
SeaBis WRITTEN 8-year money-back Guarantee (the equipment) and Warranty (the SeaBis System) at SeaBis Guarantee and Warranty,

Some will claim there is DC (battery power) in AC (shore power).  If so, then every AC appliance would burn out in a few seconds. The reason is: DC creates no Counter Motive Force (Back EMF). Verification: Wikipedia – Counter Motive Force, Back EMF: 

So do not blame the shore connection.  The SeaBis System with How to Prevent Corrosion will identify then correct the cause


SeaBis Master with How to Prevent Corrosion, explanation:

Your work is reduced by half: SeaBis Master indicates battery side causing the corrosion.  “Battery positive” or “Battery negative”.

SeaBis Master with How to Prevent Corrosion is an industrial grade mini-computer system with 20 years design life.  Compare cost – try buying an industrial grade mini computer with 20 years design life.

It is the simplest and most direct way to eliminate the CAUSE of marine corrosion. 

You do not need a Blocker when you use SeaBis Master with How to Prevent Corrosion.


Portable SeaBis:

SeaBis Master with How to Prevent Corrosion can be fitted with battery clips:

And moved to more than one battery bank, and How to Prevent Corrosion will prevent all permanent CAUSE/S of stray current. Intermittent stray current (moisture, equipment or wiring failure) requires SeaBis be permanently installed. So if you use one SeaBis Master fitted with battery clips to move SeaBis to more than one battery bank, then every battery bank must be interrogated by SeaBis Master at a maximum interval of 7 days. Then How to Prevent Corrosion will prevent the CAUSE.   Therefore, no electrolysis corrosion can occur and galvanic corrosion is easy to prevent with anodes.

Full details supplied with SeaBis Master.  SeaBis Master indications follows:

SeaBis Master System prevents the CAUSE of electrolysis corrosion.

SeaBis Master LED’s explanation:

1:  Normal (green) = there is no corrosive current
2:  Caution (amber) = very low current.  There is a risk fault may become serious
3:  Serious  (red) = visible corrosion in 6 months
4:  Critical (flashing red) = visible corrosion in 3 months
5:  AC Only (flashing red) = your batteries, electronics and yourself are at risk.  Excessive AC (110/240) on top of DC (battery).


Is very important.  AC Only flashes at more than 2 volts AC.  Normal AC level is o.o2 volt. Do not ignore it. You are warned of excessive AC in your DC. That AC halves your battery life, kills electronics and vastly increases the risk of electrocution. The cause is often shore / mains neutral and active reversed so a risk to your life or a cheap inverter or 12 to 24 volts regulator, failing alternator or generator. Diagnosis with How to Prevent Corrosion is exactly the same as stray current elimination.

ANY battery positive red LED

Can be caused by an avoidable fire risk – contact us immediately.  If you have both 12 and 24 volts, there will be very accelerated corrosion and increased fire risk.

Corrosion CAUSE Prevention Procedure:

Using How to Prevent Corrosion instructions.

Subject to proof of SeaBis purchase, we can email How to Prevent Corrosion instructions in A4 and US Letter sizes.

The SeaBis Master Traffic Light System that will instantly indicate the corrosive ability of all stray current.  You can then determine the degree of urgency of repair.

Connect SeaBis brown to battery positive. Blue to battery negative. Green / yellow to hull if metal, otherwise the engine metal body. Connections must be to clean metal with no paint, rust or grease as those will stop SeaBis working.


Diagnosis using How to Prevent Corrosion instructions:

Switch off *double pole breakers, or find the brass connection strip that joins all the battery black wires together. Disconnect one wire at a time until SeaBis Normal light is green. Leave them disconnected. Reconnect all that SeaBis indicates Normal.
* double pole breakers switch off both battery positive and battery negative with one horizontal lever.  They have two vertical parts and one horizontal joining them. The horizontal lever is used to switch off the two verticals.

The last wire you disconnected was causing stray current corrosion. As it now has no power, it is easily identified.

Multiple causes? Any that cause other than Normal (green) are additional cause/s. Leave all wire/s causing stray current disconnected.

Follow booklet supplied with SeaBis. Also, available in A4 and US Letter by contacting us with proof of purchase: How to Prevent Corrosion.

If you get any problems, contact me: email Glen Bishop


Commercial use vessels:

Using How to Prevent Corrosion.

Procedure to repair CAUSE of stray current where engine ON hours exceed 200 per year.

Using SeaBis Master System with How to Prevent Corrosion, identify sensors that cause other than Normal.  Sensors available at : A.S.A.P. Supplies in U.K. link: ASAP-UK sells Teddington senders and switches that are all correctly insulated.

To get thread exactly correct, use a thread gauge link: Thread Gauge from Fastener Retailer.

Using SeaBis Master System with How to Prevent Corrosion to identify starter motor and alternator terminal insulation that causes other than Normal.  It is often carbon build up around brush holders or bad design. Commonly corrected by automotive starter motor and alternator re-winder. Obtain wire and crimps to replace the connections that used to be made by the engine body.

If you have any difficulty, we will talk you through the entire vessel full insulation.  


False promotions developed to sell products that will not prevent stray current:

“AC – shore power causes stray current”: 

  • Very very unlikely:

Stray current corrosion is caused by electrolytic action created by DC (battery current) between damp or immersed metal or cooling system via sea to the Earth (the Earth we stand on). Electrolytic action is particles of metal being dissolved from your metal. DC is an abbreviation for Direct Current and always flows in the same direction. So continually dissolves metal. How to Prevent Corrosion will identify ALL CAUSES.  They can then be corrected.

AC (Mains/shore power) is Alternating Current that reverses direction every half cycle (Hertz or 1 divided by 50 or 60 of a second) so dissolved particles will be replaced every half Hertz. So AC cannot cause stray current corrosion. All stray current is prevented by the SeaBis System with How to Prevent Corrosion under actual live use conditions – 8 year money-back guarantee. Testimonials with verification.

External reference.  See Wikipedia – electrolysis.


“Shore power contains DC”:

  • DC in shore power AC? 

Please read the compliance plate on your kettle. There will be no DC compliance. IF there were DC in AC then there would be no Back EMF (Counter Electromotive Force) so every appliance would attempt to draw an infinite current and burn out within a few seconds – every appliance in the World burning out in a few seconds… 

External reference. See Wikipedia – Is there DC in AC?

Battery Banks – multiple.

One SeaBis may be used on multiple battery banks, with How to Prevent Corrosion.

With How to Prevent Corrosion, it will prevent ALL CAUSES, permanently.

1: One SeaBis Master with How to Prevent Corrosion will eliminate all PERMANENT causes of stray current on the battery bank it is connected to. It may be fitted with battery clips and moved between battery banks. However, that may not eliminate intermittent or new causes and stray current may occur without your knowledge, sometimes in 10 days.

2: To comply with How To Prevent Corrosion and validate our guarantee and warranty, SeaBis must be permanently installed, one to each *independent battery bank. Explanation: Every battery is a source of stray current. So permanently install one SeaBis per *independent battery bank / DC source (including regulators, reducers, generators and DC generated from AC).

*independent – All DC sources must be monitored by SeaBis more than 97% of ALL time to eliminate 97% of all causes. Parallel (joined together) battery banks  – parallel sources of DC are actually one source, so require only one SeaBis. Solution: Allow SeaBis to do its job by permanently connecting to every independent battery bank and DC source! If you have 12 and 24 volts then ALL DC sources must be permanently fitted with SeaBis Master – there will be 3 times the stray current probability, capability and severity.

With How to Prevent Corrosion, you will comply with ABYC international marine Wiring Rules.  Insurance then cannot use noncompliance as an excuse to refuse payment. Contact us and we will email them to you.

3: Time away from your vessel is excluded, as we will take steps to ensure there is no stray current while you are absent – see How To Prevent Corrosion and/or contact us with SeaBis Master results.

4: Equipment, such as bilge pump/s you cannot turn off, is treated separately. That absolutely minimises the risk.
Solution: Contact us with SeaBis Master results.

5: As always, we will support you. However, for our 8-year guarantee and warranty to be valid you must comply with How To Prevent Corrosion, supplied with SeaBis. Then ALL CAUSES of stray current will be prevented. 

6: Support. Training and diagnostic support are free with SeaBis Master System. 


Corrosion CAUSE is current, not voltage:

Explanation. Assuming you are sitting at your desk and the light is on. The element in the lamp is slowly dissipating (corroding) in the same manner as your installation / hull / engine / propeller / deck fittings. You grab a rag, and with the light still turned on, you remove the lamp. The current through the lamp element has ceased. The lamp goes out, and the element ceases to dissipate. The power to the lamp socket: 110 or 240 volts, is still applied.  

There is no point in measuring voltage – it has not changed. Measuring current would immediately show the current is zero and element dissipation has ceased. SeaBis Master System measures current through the metal being dissipated, your propeller, engine, hull deck fixtures and fittings. Only SeaBis Master measures current directly.  All other methods measure voltage. How To Prevent Corrosion identifies the cause and provides sample methods of repair.  Advice is free: email Glen Bishop 

In doubt? Ask any manufacturing jeweler how he plates gold onto base metal. The gold is your (engine / hull) damp / wet metal, and the (jewelry) base metal is the Earth.


“Anodes will stop stray current”.

A one kilogram anode produces one micro amp, or one millionth of an amp, of protective current. Stray current is commonly greater than 0.1 milli amp (1 / 10,000 amps) to several amps of current. So we would need a lot more than 1,000 kilograms of anode! I have personally measured 9 amps caused by a commercial VHF Transceiver with a 9 amp power supply – that would require 9,000 kilo grams of Anode.  It is much easier to stop the stray current.

SeaBis Master System with How to Prevent Corrosion eliminates ALL stray current, permanently, without through hull penetration, additional coatings, plating or moving parts. When stray current CAUSE is proven to be eliminated by SeaBis, anodes will stop galvanic corrosion.


“Stopping stray current is too hard” 

Only for those who make a living repairing stray current corrosion. 45+ years ago, stray current barely existed because marine equipment was correctly manufactured. Today, larger tugs, military vessels, professional vehicles, some train / signals and larger aircraft do not experience stray current because they are correctly manufactured. Most experienced Professional Fishermen whose family have been in the trade for generations know what not to buy. Use SeaBis with How to Prevent Corrosion to prove new equipment does not cause stray current.

Ohms Law:

The only electrical law you need to know:

I (current in amps) = V(voltage in volts) / (divided by) R(resistance in ohms)

* is multiplication sign

/ is divided by sign

To transpose the formula:
Replace letters with numbers
4 = 8 / (divided by) 2
8 = 4 *(multiplied by) 2 so V = I * R
2 = 8 / 4 so R = V / I

That’s it. Unless you want Watts(heat or energy) = I * V

Difficulty? Contact us. 


•How do I wire up my Boat?

Non-compliance with ABYC Wiring Rules is used to remove Insurance Companies liability. Comply, and you remove that excuse to deny liability. I talk to Owners who have just paid 50% to 90% of the value of their vessel in repairs caused by stray current. Totally preventable – follow ABYC Wiring Rules and check there are no faults in your vessel with SeaBis Master with How to Prevent Corrosion. A profit driven manufacturer has published their own ABYC Rules.

ABYC Wiring Rules must be complied with to eliminate the cause of stray current and so your insurance is valid. ABYC mandate a 3 wire system: battery positive, battery negative and bonding. No battery connection must make electrical contact with bonding. If you chose not to eliminate stray current, you will have no insurance from stray current corrosion.

ABYC Wiring Rules are recognized by all authorities, World-wide as pre-eminent, correct and legally binding. They will be used to void insurance where there is non-compliance.

ABYC Wiring Rules are at here.


Rust and galvanic corrosion versus stray current?

Rust is caused by moisture in the air allowing electric current to flow from the metal to the Earth via the air, causing the metal to dissipate. Air is a poor conductor of electricity so the process, compared to water carried stray current, is very slow.

Galvanic corrosion: Metals have natural voltages, so different metals have different voltages. The maximum difference possible being 1.2 volts (one point two volts) whereas your vessel is 12 or 24 volts. The current generation ability is limited to millionths of an amp. Therefore, galvanic corrosion is equally slow. When SeaBis Master with How to Prevent Corrosion proves there is no stray current, then anodes and bonding  and insulation will stop galvanic corrosion.  We will assist you.

Stray current is at least a million times more corrosive than galvanic.  You are connected by the water to the Earth and every vessel within at least 180 meters. SeaBis Master System with How to Prevent Corrosion eliminates ALL CAUSES of stray current. Permanently and forever. You are disconnected (insulated) from the World, so no current can flow. How To Prevent Corrosion must be complied with.

Stray current corrosion is man-made. The SeaBis System with How to Prevent Corrosion eliminates all stray current, no matter what the cause. Then anodes, coatings and plating can work as designed.  That is why we offer an 8-year money-back guarantee. The guarantee or warranty has never been claimed in 20 years with greater than 2,000 vessels.


Stray current causes.  All stray current prevented with SeaBis Master and How to Prevent Corrosion.

Please consider there were very few stray current problems 45+ years ago. The equipment was very much the same. Therefore, what has changed? Also, consider there is far more profit in spare parts than whole equipment. With How to Prevent Corrosion, we will correct this design situation.

1:  Planned Redundancy, causing purchase of expensive parts
2:  New equipment
3:  Moisture
4:  Cooling system
5:  Insulation
6:  Antenna
7: Carbon from brushes as in all motors, generators and alternators.

We will eliminate ALL causes of stray current by using the SeaBis System with How to Prevent Corrosion. We will measure the stray current, irrespective of the cause, while fully powered.  With very good accuracy and total reliability. Without disturbing the circuit in any way. We will use the SeaBis System with How to Prevent Corrosion  because it is totally accurate and reliable.

Whereas a multi meter must cause a circuit disturbance and vast inaccuracy: for a $500 multi meter, an inaccuracy of at least 2,000 to 1. Using a multimeter, you will have one chance in greater than 2,000 of any accuracy whatsoever. To prove it to yourself:


Multimeter – the truth 

Prove the truth using 2 Multimeters:

So as not to confuse them, take the battery out of multimeter A and switch it to milli amps.
Put the multimeter B on ohms and measure the multimeter A milli amps range resistance (at milli amp and Common terminals). You will find 500 to 2,000 Ohms.

Compare that to the cause of stray current – electrical short circuits of less than 1 Ohm. If you use a multimeter, your chance of success at best is 1 divided by 500 (for a $1,500 combination meter) or at worst 1 divided by at least 2,000 (for most multimeters). Causing a failure rate of 2,000:1. A multimeter has unacceptable odds, and they get worse – see next paragraph. Use SeaBis: It is accurate and safe.

If you use a multi meter, you are measuring voltage developed across a resistor connected in series. Not only of no use, but confusing and potentially lethal: 

Battery explosion, a real threat to your life. Prevented with SeaBis Master and How to Prevent Corrosion.

Risk of battery explosion because of explosive gasses. ALL batteries generate hydrogen gas. That is the smallest particle of everything and will permeate everything. Multimeters must cost more than $800 before they may be fitted with HRC fuses. Therefore, multimeters cause lethal risk. The Zeppelins were filled with hydrogen gas.  They all exploded in flames. Use SeaBis Master with How to Prevent Corrosion.  It is accurate and safe.

Locating the CAUSE/S with How to Prevent Corrosion.

All causes are electrically in parallel – the solution to locating the causes:

When, as is common, there is more than one cause, they are in parallel. Therefore, if A and B are causes and A is disconnected, B will continue causing stray current. If you then think “well, A was not the cause, so I will reconnect A and disconnect B…”   then you will never eliminate the cause. So, the correct procedure is to disconnect connections / double pole switches until SeaBis indicates Normal or Caution, then momentarily connect or touch on one circuit at a time to test it. Watch SeaBis respond. 

  • The same principle applies to diagnosis: Always disconnect until you have a Normal, then momentarily connect one circuit at a time to test it. If it causes stray current disconnect it and label it stray current, and then you have Normal again so test the next. Any that do not cause stray current (SeaBis stays on Normal) should be reconnected.

Caution LED: 

It is caused by an extremely low level of stray current. Corrosion may just be visible in a year. Common causes are a very small fall in insulation / very small coolant leakage into a sensor, poorly designed electronics such as in energy sensors in some radars. There is a risk the fault may become serious. It is eliminated in exactly the same manner as stray current prevention.

The areas affected worse are those with increased temperature (headers) and softer metal such as radiators; and hulls, propellers, gearbox, engines and upper deck fixtures and fittings. The water in the top 300 milli meter adjacent to the hull is always warmer than that deeper underwater, so carries most of the stray current. The air also carries stray current wherever Relative Humidity is greater than 10%. (humor – Gobi Desert has greater than 10% occasionally).

Flickering or multiple LED’s: 

Is the AC Only LED flashing more than 3 times?  If so, AC content on top of DC is seriously excessive.  If multiple LEDs are flashing, then AC is extremely excessive. AC is normally 0.02 volts. If it exceeds 2.0 volts for more than 3 seconds, the AC Only flashes.  A risk to life exists.  All work on Mains or shore or inverter power requires an A Class License. Diagnose both by progressive disconnection as normal stray current prevention.


How do I know you and How to Prevent Corrosion are correct?

See Testimonials with verification for 20+ years. In addition, I know of no other stray current prevention product with an 8 year, publicly available written money-back guarantee and warranty.  We provide an 8-year guarantee because we know we are 100% correct. We provide 8 years free support as new causes will occur.


Bonding question:

” Should the fuel tank bonding as well as all other outer hull and thru hull mounted metal be connected to all metal, not the DC system?” •Yes. The Bonding connects all metal that can get damp to wet, so reducing the inter-metal natural voltage, so reducing galvanic corrosion. NEVER connect bonding or any metal that can get damp or wet to any DC, as that will cause accelerated stray current. NEVER connect DC to fuel tanks – you will pass 80% of total current through the tank and its content – that has caused death by fuel explosion. The bonding system is never connected to AC or DC whatsoever.


AC, Mains or shore power, question:

I am unqualified to offer advice. Get an A Class Electrician to do a SAFETY CHECK on AC.  He must be on site and issue a Compliance Certificate. I believe the Inverter AC Earth should connect to the Mains Earth and the hull.

The critical prerequisite is that SeaBis with How to Prevent Corrosion MUST indicate Normal, permanently on all DC.  With everything at full power use.  Equipment brings in extra circuitry at full power.

The Inverter AC MUST be Open Circuit to all DC. It MUST NOT fire AC back into the battery – that will cause battery failure, electrocution risk and kill electronics. Ignoring AC Only LED flashing will cause very expensive damage and reduce your guarantee and warranty to 10 days – the time taken for extreme stray current to cause corrosion you can see.


Battery – Multiple installations with How to Prevent Corrosion.

Where the battery banks can be connected in parallel (connected together), usually for charging and reserve energy, often by “Both” or Emergency” battery switch positions, use one SeaBis Master connected to the House bank and parallel all banks at least 97% of time. When the other banks are switched in circuit, SeaBis will automatically interrogate them. If they cannot be connected in parallel, there are two choices:

1: This procedure will eliminate all permanent causes, but battery bank monitored time will NOT be adequate to eliminate intermittent or new causes:  We or you fit battery clips to SeaBis Master and move it between battery banks. At a maximum time interval per bank of 7 days. How to Prevent Corrosion will identify stray current present at the time of monitoring, only. This procedure will void Guarantee and Warranty. We will not be responsible at all when batteries are inadequately monitored.

2: When you want 100% elimination of stray current, then permanently connect one SeaBis per battery bank. Use How to Prevent Corrosion.  Treat as commercial use with engine ON hours greater than 200 per year. Then you will get 100% elimination of ALL stray current, permanently and our Guarantee and Warranty will apply.


Remember: If you monitor all battery banks less than total time, there is a proportional or greater risk of ongoing stray current without your knowledge. SeaBis can only monitor the circuit it is connected to.

Where the battery banks cannot be connected together, and for all vessels using 12 and 24 power supply, a SeaBis Master MUST be permanently connected to EVERY battery bank.  Failure to do so will cause failure to detect stray current and void Guarantee and Warranty. SeaBis cannot monitor that it is not connected to.

Rig / Platform and some industrial or ship installations, may need special actions, depending on SeaBis Master with How to Prevent Corrosion results: Email Glen Bishop

If you use one SeaBis and move it battery bank to battery bank or use a switch to select or parallel battery banks, there are risks of stray current and very expensive corrosion.  Some get away without excessive corrosion.  Some forget or wire incorrectly, causing 1% to pay 90% to 95% of the value of their vessel in repairs when batteries are unmonitored for a CUMULATIVE time of greater than 200 hours (10 days) on one year.



Electrolysis and stray current prevention.

The 100% absolute method:

Permanently install one SeaBis Master per battery bank. This is the only method to obtain 100% and permanent protection. SeaBis will instantly alert you should ANY stray current occur. Then our Guarantee and Warranty apply. 


Rig/Platform/boat/industry has more than 5 battery banks.

Can you assist?

Yes. The cause/s are permanently eliminated by the SeaBis System. Contact: email Glen Bishop or phone +61 (0)417 878 773.  We can set up a World-wide audio / video link via Zoom or Skype or WhatsApp: click here.


Multimeter Question:

My Technician uses a multimeter, we cannot find the cause:

The use of a multimeter cannot find the cause. It will waste your time and money and risk your life while stray current corrosion will continue.

Using a multimeter on any current range not only cannot find the cause, but is also taking an immediate risk of death by battery explosion. Never use a multimeter on milli amp or amp ranges near any connection to any battery.

Using a multimeter on ohms cannot eliminate stray current. The multimeter tests voltage on current ranges and at one volt (even if it has a 9 volt battery whereas your vessel is at 12 or 24 volts) at one millionth of an amp. It will waste your time and money while stray current corrosion will continue.

My background:

My stray current knowledge started in year 1962 with my attempt to qualify for the next stage of my training. I was a tender 19-year-old, had joined the Royal Navy 6 months previously and was determined to improve my prospects. I volunteered for a 3-month duty on HMS Venus. A warship – type 14 frigate and intended for training potential seamen. These were DC ships. DC – direct current – it flows in one direction only. That causes particles of metal to be permanently dissolved to the Earth via the sea.

My duty on-board HMS Venus was very specific: To test the insulation of ALL the DC supply to all equipment. There was no live testing equipment, as SeaBis is now some 60+ years later, so we had to remove power, disconnect the equipment being powered and insulation test. It was a compromise done in writing, signed and witnessed. My neck was on the chopping block. 

Today, using SeaBis Master and How to Prevent Corrosion, we prevent all causes on ENTIRE vessels.

There is no compromise. We are accurate to 10 millionths of an amp (see Ohms Law explanation above). That is why we provide an 8-year money-back guarantee.  How To Prevent Corrosion must be complied with. 

So the cause of stray current has been well known since prior to 1962. So why is it prevalent now? The same reason, as profit in spare parts is vastly greater than whole equipment. We will correct this situation. The correction will use SeaBis Master System with How to Prevent Corrosion.  Be visible to you, permanent and at low cost.

Glen Bishop of SeaBis.

Suggested reading:
Marine Electrolysis Corrosion CAUSE Prevention here.
How to Prevent Marine Corrosion here.

Corrosion CAUSE prevented, permanently
8-year no reason money back guarantee, warranty and technical support, free
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