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How to Prevent Marine Corrosion. Language translator at button on page bottom – left.

Corrosion CAUSE prevented, permanently
How to Prevent Marine Corrosion. 8-year money back guarantee.

How to Prevent Marine 
Corrosion – Permanently.

How to Prevent Marine Corrosion. Photographic proof the SeaBis Master System prevents ALL CAUSES of stray current. So, 100% prevents corrosion. Permanently.  No additional coating, plating or through hole. Very little skill required.  The first two photographs are before SeaBis, the next two are after SeaBis after a year submerged.

Verify that which we state is true:  

Note that the Wikipedia apparatus power supply is red and black.  So, DC or battery power.  Confirmed in the first paragraph text.  It is not AC or mains power.  So why use a device in AC mains power such as a transformer or “Blocker”.  Verify, click:  Wikipedia – electrolysis.

The reason we provide an 8-year guarantee and warranty is we are 100% correct

How to Prevent Marine Corrosion. Proof we are genuine:

Glen Bishop is CEO of SeaBis. Surveyor to all Class Societies, World-wide. This website and my company are registered in Australia, so must comply with Australian Laws. Those laws are strict. 

Verification: Australian Business Number 27008191848. 

I ask you to spend two minutes to read this and so avoid a 1% risk of loss of your vessel.  Read up to “The remainder is not necessary“.
We will guide you step by step to prevent ALL the CAUSE/S of corrosion. Permanently. In 3 simple steps.

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 Marine Corrosion – free.

How to prevent marine corrosion. 3-step procedure:

Step : Connect SeaBis Master:

Blue to battery negative, brown to battery positive, green/yellow current sense, to metal hull or metal body of engine.

Step 2: SeaBis indicates (stray) current corrosion ability.

Switch off or disconnect equipment until SeaBis Master indicates Normal (green).  The last disconnected was a cause. 

Step 3: Prevent the cause. 

To repair, see How to Prevent Marine Corrosion supplied with SeaBis Master or contact us.

SeaBis Master System prevents the CAUSE of electrolysis corrosion.
Marine corrosion CAUSE prevented, permanently

SeaBis Master LED’s explanation:

SeaBis Master halves your work by indicating battery negative or positive.

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 within 3 months. I regularly experience 10 days.
5:  AC Only (flashing red) = your batteries, electronics and yourself are at risk. A common cause is Mains or Shore power Active, Neutral or Earth reversed. AC (110/240) on top of DC (battery) exceeds 2 volts.  It is normally 0.02 volt.

The remainder is not necessary to complete prevention of the CAUSE of corrosion. We will guide you through corrosion CAUSE prevention – 100%. Contact us.


Table of Contents


How to prevent marine corrosion. Understand, detail:

1: Stray DC (battery) electrical current is the actual energy that dissolves your metal. SeaBis Master measures and indicates DC current as DC 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. However, without knowing ALL the other factors, measuring voltage is valueless. Corrosion will escalate.  Current is the energy that causes all corrosion. We term that current Stray Current.  SeaBis Master System 100% prevents stray current.

3: 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 Marine Corrosion will isolate shore as the CAUSE. In more than 2,000 vessels cleared of corrosive current, I have never known the Mains or Shore Power to be a cause. 

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

5:  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.

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 marine corrosion, permanently. The proof are testimonials and 8 years guarantee (physical properties) AND Warranty (functional properties) – in writing.  Proof we are genuine, click: here. 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.


If in any difficulty please contact me, Glen Bishop

How to Prevent Marine Corrosion

Diagram explanation of why SeaBis System is 100% Successful:

Voltage versus current – critical importance. 

How to Prevent Marine Corrosion, CRITICAL.

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 (stray) current, then switching off equipment until the stray current ceases then SeaBis Master indicates Normal, WILL identify the CAUSE.  How to Prevent Marine 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 (stray) 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 Marine Corrosion, now and permanently.

Stray current – the ONLY CAUSE:

It 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. And works 100%.  No additional anodes, coating, plating, through hole or moving parts. Then the anodes, coatings and plating can work as designed.

SeaBis Master System accuracy:

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 Marine Corrosion, repairs it.

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

SeaBis Master System, with How to Prevent Marine 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 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 explanation:

Galvanic corrosion is ONLY caused by two different metals nearly touching in a conductor, such damp air or water.  The only examples I know of are a stainless-steel ladder touching an aluminium hull or an aluminium cupboard with stainless steel knobs, both 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 corrosion 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 or not at all, then stray current is the cause.

Stray current is the ONLY cause of all this corrosion:

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

Stray current corrosion is caused by wiring or equipment defects onboard your vessel – 99% of the time.  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 Marine 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:

A year submerged:
After SeaBis. Antifouling works as designed.
After SeaBis. Utopiall 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. Utopiall 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 Marine Corrosion, instructions must be complied with.

Testimonials at:

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 Marine 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 Marine 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 Marine 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 or aluminium cupboard with stainless-steel handle, both without insulation. A little intelligence, 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 Marine 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. 

SeaBis WRITTEN 8-year money-back Guarantee (the equipment) and Warranty (the SeaBis System) click: 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). Verify: Wikipedia – Counter Motive Force, Back EMF: 

Shore connection:

It is extremely unlikely the shore connection is the cause. The SeaBis System with How to Prevent Marine Corrosion will correctly indicate, then correct, the cause.

Reduce your work by 50% with How to Prevent Marine Corrosion:

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

Life expectancy of SeaBis Master:

SeaBis Master with How to Prevent Marine 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. 

Blocker or transformer is not required:

You do not need a Blocker or transformer when you use SeaBis Master with How to Prevent Marine Corrosion. SeaBis Master will flash red in the extremely unlikely (impossible) instance where shore power causes corrosion. 


Portable SeaBis:  How to Prevent Marine Corrosion.

SeaBis Master with How to Prevent Marine Corrosion can be fitted with battery clips.  There are limitations:

SeaBis Master may be moved to more than one battery bank, and How to Prevent Marine 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 Marine Corrosion will prevent the CAUSE.   Therefore, no electrolysis corrosion can occur and galvanic corrosion is easy to prevent with anodes.


Using How to Prevent Marine Corrosion:

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

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

Commercial use vessels:

Using How to Prevent Marine Corrosion.

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

Using SeaBis Master System with How to Prevent Marine Corrosion, identify sensors that cause other than Normal.  Replacement 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 Marine Corrosion to identify starter motor and alternator terminal insulation that causes other than Normal.  The cause 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 Marine 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 Marine Corrosion under actual live use conditions – 8 year money-back guarantee. Testimonials with verification. 

“Shore power contains DC”:

  • DC in shore power? 

Please read the compliance plate on your TV, microwave, 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?

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 multiplied by 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) = I * V

Difficulty? Contact us. 

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 – a 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 Marine 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 Marine 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 Marine Corrosion.  Be visible to you, permanent and at low cost.

Glen Bishop of SeaBis.

Suggested reading:
Marine Corrosion CAUSE Prevention here.

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