How to Stop Corrosion – Training.

How To Stop Corrosion – Training.

Stray current is the cause of 97% of all marine corrosion.

The CAUSE of corrosion is direct current (DC as in batteries) creating the stray current that creates electrolysis corrosion.

SeaBis Master System consists of SeaBis Master and How To Stop Corrosion. How to stop corrosion identifies the type of corrosion, understand it then prevent it, permanently.  No additional coating, plating, moving part or through hull penetration. Permanently. Forever. No exceptions. In writing.

Stray current dissolves your propellor, gearbox, engine and hull so the metal under coatings and plating so causing them to lift off the metal. SeaBis System with How To Stop Corrosion prevents the cause of stray current. Permanently. Then the anodes, coatings and plating will work as designed.

Verification that we state is true: Wikipedia. Note the electrolysis test instrument is supplied with Direct Current (DC). Red and black wires. The explanation details that specifically. Batteries supply DC, only. Without SeaBis they are the source of stray current. SeaBis System with How To Stop Corrosion prevents stray current. That is why we provide a 8 year guarantee AND warranty.

How to stop corrosion. Marine corrosion learning:

Takes an hour or two. If you do not have spare time there is no need to read the following. We will step you thru preventing the CAUSE of marine corrosion. Contact: email your question to Glen Bishop. Voice at Skype (free PC to PC) name: seabis1 or 61 (0)417 878 773. Other methods of contact here.

There is a need to understand the difference between voltage and current:

Voltage is the POTENTIAL for current to flow.
Current is the ACTUAL energy flowing.
How To Stop Corrosion  with SeaBis Master System prevents the CAUSE of marine corrosion, stray current, permanently.
SeaBis Master measures current as current to an accuracy of ten parts in one millionth amp. The SeaBis System identifies the CAUSE and repairs it.

So, measuring voltage MUST fail. That failure will cost you increased corrosion in an *exponential manner.
*Exponential: 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. So, increasing marine corrosion, exponentially. I have witnessed a 10-day time period from no to extreme corrosion many times.

SeaBis Master measures current as current to an accuracy of ten parts in one millionth amp. The SeaBis System with How To Stop Corrosion identifies the CAUSE and repairs it, exclusively. So How To Stop Corrosion  actually does just that.

Technical explanation (easily understood):

SeaBis Master System with How To Stop Corrosion eliminates the CAUSE of stray current corrosion – termed 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 marine electrolysis. All will be prevented, permanently.

Galvanic corrosion

Is caused by two different metals being in very close proximity in a conductor such as water. The only example I know of is a stainless steel ladder against an aluminium hull without insulation.  Galvanic is a million times slower than stray current corrosion and is often accelerated by stray current. Anodes, when stray current corrosion, electrolysis, is eliminated, will stop galvanic and should last 3 to 4 years. If they do not or are coated in a white hard substance or jelly or are not dissolved or dissolved far too fast then stray current is the cause.

Stray Current Corrosion, termed electrolysis.  SeaBis Master with How To Stop Corrosion  will stop the CAUSE of stray current.

Stray current dissolves your metal:
Stray current (electrolysis) corrosion to engine leg in 14 days:

How to stop corrosion - an outboard leg dissolves
Additional photos for identification of marine electrolysis at
I have no photos of galvanic as it is rare.

Stray current or electrolysis corrosion is caused by wiring or equipment defects on-board your vessel. I witness stray current destroy commercial propellers or hull in 10 days, many times every year. It is 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 Master with How To Stop Corrosion pays for itself, very quickly. SeaBis System prevents the stray current CAUSE. So saving you many thousands dollars. How To Stop Corrosion – involves identifying, understanding then preventing the CAUSE of stray current.

That stray current by electrolytic action, termed electrolysis, creates marine corrosion.

Our Guarantee, Warranty and diagnostic support: The reasons we provide an 8-year money back guarantee (the equipment) and warranty (the function) are, 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 Stop Corrosion instructions must be complied with.


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! So use SeaBis Master System to prevent the CAUSE, completely and permanently.

So How to stop corrosion does not use Anodes.  It will prolong the life of Anodes.

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 increases exponentially. The reason is corrosion is caused by CURRENT flow to the Earth. They will measure the COMBINED VOLTAGE of every vessel within 200 meters and that of the Earth. Not current. The result is misleading information, potentially a battery explosion and exponential corrosion. Therefore use SeaBis Master System 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 stop corrosion  ensures the guarantee and warranty are effective.

Why buy a Blocker?

Some will try confusion by calling Blocker a Galvanic Isolator! Don’t be deceived. AC – Mains / shore power CAN NOT be the cause. VERIFY their claims. Ask for their WRITTEN guarantee. Read it. SeaBis WRITTEN 8-year money back Guarantee and Warranty at SeaBis here.
AC or shore power cannot be the cause so what does the Blocker achieve?

Explanation of Blockers function:

AC is the abbreviation for Alternating Current. It reverses direction every half Cycle or Hertz. So IF a particle is removed in the first half Cycle it will be replaced in second half Cycle. Therefore AC cannot cause electrolysis. 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).  It has no change in direction so cannot create Counter Motive Force. Verification: Wikipedia – Counter Motive Force, Back EMF: So do not blame the shore connection. The SeaBis System will correct the cause. How to stop corrosion proves a Blocker is not necessary.

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 we test and eliminate all causes on ENTIRE vessels.

We use How To Stop Corrosion coupled with results from SeaBis Master.  That produces a system that prevents the CAUSE, permanently.

There is no compromise. We are accurate to 10 millionths of an amp (reference Ohms Law explanation on last page). 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 be visible to you, permanent and at low cost.

SeaBis Master, explanation:

1: How to stop corrosion coupled with SeaBis Master produces a system that prevents the CAUSE, permanently.  SeaBis Master is 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 System.

2: SeaBis Master can be fitted with battery clips, moved to more than one battery bank and following How to Stop 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 and move it:

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 10 days. Then no electrolysis corrosion can occur and galvanic corrosion is easy to prevent with anodes.

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

•SeaBis Master LEDs explanation:

Corrosion CAUSE prevention. Permanently. 3 simple steps.


Normal (green) you are absolutely safe from stray current causing corrosion.
Caution (amber) very small amount of low level current causing minor corrosion.
Serious (red) (LED lit solid not flashing) high current causing stray current is present. Corrosion visible within 6 months.
Critical (red flashing) large current causing visible corrosion within 3 months. Two $5,000 propellers destroyed in 10 days.
AC Only (red flashing) warns you of excessive AC in your DC. That AC halves your battery life, kills electronics and vastly increases the risk of electrocution. The cause is usually shore / mains neutral and active reversed or a cheap inverter or 12 to 24 volts regulator, alternator or generator. Diagnosis is exactly same as stray current elimination.

ALL battery positive red LEDs can be caused by a fire risk – contact us immediately. If you have both 12 and 24 volts there will be very accelerated corrosion and increased fire risk.

How to stop corrosion  contains full instructions.

Stray current that causes electrolysis can be prevented.


Marine stray current and electrolysis corrosion CAUSE prevention procedure:

As booklet supplied with SeaBis: How to stop corrosion.

SeaBis Master traffic light system that will instantly indicate the corrosive ability of all stray current.

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, corrosion or grease as those will stop SeaBis working.


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 LED is green. Leave them disconnected.
* 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.

Reconnect all those NOT causing stray current. Any that cause other than Normal (green) are additional cause/s. Leave all wire/s causing stray current disconnected. Follow How To Stop Corrosion.

All equipment causing stray current now has no power so is easily identified.

Follow How to stop corrosion supplied with SeaBis. If you get any problems contact me: email Glen Bishop

• How to stop corrosion in commercial vessels.  Prevent CAUSE of stray current where engine ON hours exceed 200 per year – (Commercial use vessels):

Senders / Sensors:

Using SeaBis 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. So battery negative is insulated from the metal body.

Starter motor and Alternator:

Using SeaBis, identify by disconnection, starter motor and alternator terminal insulation that causes other than Normal. It is commonly corrected by automotive starter motor and alternator re-winder. Some engine manufacturers sell kits.

Fit additional wiring:

Obtain wire and crimps to replace the connections that used to be made by engine body with permanent wiring.

If you have any difficulty we will talk you through entire vessel full insulation. Then you will comply with ABYC and How To Stop Corrosion.


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

“AC – shore power causes (DC) stray current”.

•Impossible: 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 abbreviation for Direct Current and always flows in the same direction. So continually dissolves metal. 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 eliminated by the SeaBis System and How To Stop Corrosion under actual live use conditions – 8 year money back guarantee and warranty.

DC in shore power AC?

Please read the compliance plate on your kettle. There will be no DC compliance or tolerance. 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… Reference Wikipedia – Is there DC in AC?

“Anodes will stop stray current”.

Impossible: 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 amp) too 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 follow How To Stop Corrosion and stop the stray current.
SeaBis Master System eliminates ALL stray current, permanently, without thru hull penetration or additional coatings or plating. 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. 25+ years ago stray current barely existed because marine equipment was correctly manufactured. Today, larger tugs, professionals where there is generations of experience, most military, larger Police and most fleet managers know what NOT to buy.

SeaBis Testimonials with verification.


One SeaBis may be used on multiple battery banks.
Follow How To Stop Corrosion.

1: One SeaBis Master  with How To Stop Corrosion will prevent 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 prevent intermittent or new causes and stray current may occur without your knowledge, sometimes in 10 days.

2: To comply with How To Stop 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. Parallel (joined together) battery banks – parallel sources of DC are actually one source so require only one SeaBis. 
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. 24 volts, 12 volts and the difference.

Comply with How To Stop Corrosion, then you will comply with ABYC international marine Wiring Rules.

Insurance then cannot use noncompliance as an excuse to refuse payment.

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 Stop 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 minimizes 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 Stop 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 with How To Stop Corrosion.

Stray current corrosion is caused by electrical 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 hull / engine / propeller. You grab a rag, and with the light still turned on, you remove the lamp. The lamp goes out and the element ceases to dissipate. The power to the lamp socket: 110 or 240 volts, is still applied. So measuring voltage only wastes your time and money. The current through the lamp element has ceased.

There is no point in measuring voltage – it has not changed. Measuring current would immediately show the element dissipation has ceased. The SeaBis System measures current through the metal being dissipated, your propeller, engine or hull. Only SeaBis measures current directly. All other methods measure voltage. Coupled with How To Stop Corrosion the CAUSE is prevented.

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. 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 to prove new equipment does not cause stray current.  If it does use How To Stop Corrosion to prevent it.

Stray current causes:

•These are probable causes:
Please consider there were very few stray current problems 25+ years ago. Modern equipment is better. So what has changed? Also consider there is far more profit in spare parts than whole equipment. We will correct this design situation.
Amongst all the causes are Planned Redundancy causing purchase of expensive parts, new equipment, moisture, cooling system, failing insulation, antenna damage and carbon brushes as in all motors, generators and alternators. We will eliminate ALL causes of stray current by using the SeaBis System.

We will measure the stray current, irrespective of the cause, while fully powered and with very good accuracy, total reliability and safety. Without disturbing the circuit in any way. We will use the SeaBis System with How To Stop Corrosion because it is totally accurate and reliable.

•Diagnosis: All causes are electrically in parallel. Using How To Stop Corrosion.

As detailed in How To Stop Corrosion: When, as is common, there is more than one cause, they are in parallel. So 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 or use double pole breakers / switches until SeaBis indicates Normal 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: 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 in a sensor, poorly designed electronics such as in energy sensors in radars. It is corrected in exactly the same manner.

The areas affected worse are those with increased temperature (headers) and softer metal such as radiators; and hulls and propellers. The water in the top 300 milli meter adjacent to the hull is always warmer than that deeper under water 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).

Using a multi meter:

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 multi meter you will have one chance in greater than 2,000 of any accuracy whatsoever. To prove it to yourself:
Prove a Multi-meter cannot tell you the truth using 2 multi-meters:
So as not to confuse them, take the battery out of multi meter A and switch it to milli amps. Put the multi meter B on ohms and measure the multi meter A while A is on milli amps range, resistance (at milliamp and Common terminals). You will find 500 to 2,000 Ohms. 

Compare that to the cause of stray current – electrical insulation failure or short circuits of less than 1 Ohm. If you use a multi meter 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 multi meters). Causing a failure rate of 2,000:1. A multi meter has unacceptable odds and they get worse – next paragraph. Use SeaBis: It is accurate and safe.

Multi meter is not only of no use but confusing and potentially lethal:

Add the risk of battery explosion because of explosive gasses. A multi meters fuse will NOT provide protection. Even “sealed” batteries generate hydrogen gas. That is the smallest particle of everything and will permeate everything. The Zeppelins were filled with hydrogen gas. They all exploded in flames. Use SeaBis Master with How To Stop Corrosion. They are accurate and safe.

I use a multimeter, we have problem:

The use of a multi meter cannot find the cause. It will waste your time and money and risk your life while stray current corrosion will continue.
Using a multi meter on any current range not only cannot find the cause but is also taking an immediate risk of causing death by battery explosion. Never use a multi meter on milli amp or amp ranges near a battery.

Using a multi meter on ohms cannot eliminate stray current. The multi meter uses one volt (even if it has a 9 volt battery) at one millionth of an amp. It will waste your time and money while stray current corrosion will continue.

Ohms Law; the only electrical law you need to know:

I (current in amps) = V(voltage in volts) / (divided by) R(resistance in ohms)
So R=V/I. To transpose formula substitute letters for numbers – easy! To expand picture, right click, Open image in new tab.

Ohms Law - the only Law you need to know

Watts = Volts * (times) amps

A 10 watt mast head light draws 10 / (divided by) 12 volts = 0.8 amps.
A 50 amp Alternator charging a 200 amp battery from flat will take more than 4 hours because of losses.
A 4 or 6 cylinder engine starter motor will draw 170 amps. So a 200 amp battery, even if new, is barely large enough.


Best regards,
Glen Bishop RN rtd. Assoc. Eng. IREE
E-mail: [email protected]
Skype name: seabis1.  Free computer to computer: Download Skype
Phone: Australia 61 Office or mobile (cell) (0)417 878 773
Podean Electronic Industries – registered in Australia. trading as SeaBis -registered trade mark. ABN 27 008 191 848
2/5 Ninth Street, Millicent, South Australia 5280