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devocean
02-03-2005, 08:19 AM
Mate told me I should never leave the battery in the boat as it causes severe electrolysis and will stuff the boat in no time at all. Is this true?

Morlers
02-03-2005, 08:53 AM
As I understand it, if there happens to be a short to the metal hull (not glass) or the hull is used as ground (as in a car) then yes, electrolysis will occur. #Boats should always be wired with both +ve and -ve wires going to apparatus.

Its a good idea to isolate the battery when not in use so as to prevent any leakage from left on switches that will flatten the battery or cause early sulfation from battery being left in a partially discharged state.

I am no electrician, but the above is what I have gleaned over the years. #Hope it helps

:) :)

Morlers

NQCairns
02-03-2005, 09:18 AM
I think it does also! I have one patch that gets worse each time I forget to disconect the battery. Once disconected the problem are gets no worse even after a 3 month layup, it's quite dramatic and has sold me on the issue, No part of my wireing is earthed to the hull in any way except through the engine and control cables. nq

BladeRunner
03-03-2005, 04:08 PM
Just a hint when the boat is of a alloy make, place an anode on the keel below the water line this will help reduce any electrolysis that may accour from battery leakage
position just about the back some where .The other surgestions are good isolation switch diso the battery. If you would like more advise PM me .

BladeRunner

whichway
03-03-2005, 11:28 PM
I remove the sounder from my boat when not in use. There was a green stain between the two terminals on the power supply plug and a fair bit of corrossion within the plug. The sounder supplier said that over time, moisture would condense out on the plug and start to short out the two terminals, leading to corrossion. Doesn't occur if you leave the sounder connected apparently.

Probably not quite what you are talking about, but still interesting

Regards

Whichway

BladeRunner
04-03-2005, 02:49 PM
whoops I thought you was refering to the boat and the electrics you ran .12 volts
any way if I can help PM me
Blade

ba229
04-03-2005, 03:09 PM
Mate told me I should never leave the battery in the boat as it causes severe electrolysis and will stuff the boat in no time at all. Is this true?

Tell your mate it is a load of crap.

Kerry
04-03-2005, 04:38 PM
Sounds like a load of crap as well #::) That is if your boat is actually wired correctly.

And as for all those who might want to run out and fit an additional anode to the keel then take a step back a deep breath and think real hard about that one as too much protection in the wrong place of the wrong type can generally be worse than what is fitted to the standard outboard.

Cheers, Kerry.
#

BladeRunner
06-03-2005, 03:38 PM
Kerry please explain your theory so we can understand what it is you are trying to say .
The question was electrolysis in boats not as he then changed it ,to terminals on a what ever [smiley=hammer.gif]

BladeRunner [smiley=bandana.gif]

Kerry
06-03-2005, 04:51 PM
Kerry please explain your theory so we can understand what it is you are trying to say .
The question was electrolysis in boats not as he then changed it ,to terminals on a what ever # #[smiley=hammer.gif]

BladeRunner # [smiley=bandana.gif]


Well BladeRunner maybe we could start by not calling this issue what it is #:D electrolysis #??? the best place to leave electrolysis is in the hair studio.

Anyway in simpe terms too many anodes, "over protection", placed in the wrong places can have problems as does too few anodes, savvy.

So what's your point about to terminals on a what ever ::) did I mention terminals ???
Cheers, Kerry.

basserman
06-03-2005, 05:57 PM
the best place to leave electrolysis is in the hair studio.

Cheers, Kerry.


Gezz kerry your starting to scare me now ;) [smiley=clown.gif]

NQCairns
07-03-2005, 02:26 AM
Now I am simply confused! :-/

Kerry
07-03-2005, 05:23 AM
Confused Nq :-X Electrolysis is a widely misused term, often used when referring to boat corrosion issues but generally used incorrectly. Electrolytic corrosion and Galvanic corrosion are NOT electrolysis and in most respects the placing of anodes on a vessel basically does absolutely nothing for Electrolytic corrosion, which can be caused by incorrectly installed battery systems.

Electroylic and Galvanic corrosion are also quite different based on the source of the current and prevention methods required.

Cheers, Kerry.

BladeRunner
07-03-2005, 03:59 PM
Kerry let me diverse a bit. Not knowing your back ground or knowledge of such maters, people still read these posts .So in reply to the boat electrolysis an anode attached to a aluminium boat where electrical system is being use say a 12 volt DC battery or a 3.5 Kw generator, mind you its aluminium we are talking
There is always a possibility of a reaction when in salt water wouldn’t you agree ? so I suggested he might like to fix an anode to the keel of his boat which would reduce the affect to aluminium and white powder
build up that would coat the hull on the inside of the vessel .Would stand out like dog b-lls .

As for a bad hair day. You wrote Electroylic and Galvanic corrosion are also quite different based on the source of the current and prevention methods required.
Tell me you prevention method ?why should / could current run through the boat?
Ever herd of a magnetic field . Electrolysis or what you call it Electroylic where
Galvanic fits in you tell me .

Now as for the terminals some one said they had corrosion on a sounder or something I didn’t expect to justify my comments and I apologise to that person sorry .

BladeRunner

Kerry
07-03-2005, 05:32 PM
Bladerunner, I would call the difference (in boat terms) between electrolyic corrosion (mind you no relation to electrolysis) and Galvanic corrosion is that one generates the current internally and the other the current has to be provided externally.

An anode as in (sacrificial anode) being the least noble will take the heat from the stuff one wants to protect and Galvanic is the big daddy of problems in tinnies.

Simply fixing an anode somehwhere on the keel might do what? I'm not even going to hazzrd a guess at that one but dwell on the side of caution as all this stuff can be black magic in some cases. If it's not the correct andode for the job or too many of them then problems can occur.

One thing with all of this is that the general thinking is that stainless is good in a saltwater environment and alloy is not quite so good and where the 2 meet the alloy is the weakest link.Well that all depends on the relative surface areas of the material in question.

A alloy rivet in a piece of stainless, the stainless will eat the alloy, no question, a stainless rivet in a piece of alloy, then the alloy will chew the stainless up into a white powered mess, no question.

Mate, if you don't think stray currents can't/won't/don't run through a boat then buy yourself a nice alloy boat and park it up in a marina ;D You might wonder what the sizzle is and you not even cooking sausages

Corrosion on terminals in many instances can be bad maintenance but without seeing what the corrosion looks like then it's rather a wild guess.

Cheers, Kerry.

ba229
07-03-2005, 06:26 PM
Mate, if you don't think stray currents can't/won't/don't run through a boat then buy yourself a nice alloy boat and park it up in a marina #;D You might wonder what the sizzle is and you not even cooking sausages

I might add to that. The original question was "does leaving a battery in a boat cause electrolysis?"

Electrolysis as defined by my dictionary is "the conduction of electricity by an electrolyte"

Electrolyte is defined as " a solution or molten substance that conducts electricity"

So lets add those two definitions together. "The conduction of electricity by a solution or molten substance that conducts electricity"
(lol I know it repeats itself a bit but it is just my example)

So does leaving a battery in a boat do this?

Refer to my first answer.


Tell your mate it is a load of crap.

Regards
Alex

devocean
08-03-2005, 08:54 AM
So will it rust the boat?

ba229
08-03-2005, 11:14 AM
No

BladeRunner
08-03-2005, 04:07 PM
Kerry you know your stuff or you have gone to a lot of trouble
I will get back to you soon
Blade
By the way as at a guess I would say the blue .If they are true pictures

ba229
08-03-2005, 06:44 PM
That surely means something to someone Blade ;D

baldyhead
09-03-2005, 01:40 PM
Kerry, you are spot on with the too many/too few scenario. I had a play around with adding more anodes and found that I had to remove them as they had the opposite effect and started to remove some of the unpainted skeg. Once removed the corrosion stopped. Good call M8......cheers baldy

BladeRunner
10-03-2005, 03:24 AM
This last post is a bit strange anodes every where adding to what, how big is your boat baldyhead?
Kerry you either do a lot of research or you know your stuff .
I am going to leave this one alone now it has been great jogging questions /answers with you .
I will watch with great intent. I only have one sacrificial anode on my tinne and it is doing its job .
Regards
BladeRunner

finga64
10-03-2005, 04:32 AM
Fellas, fellas, I am an electrician and electrolysis is caused by differences in potential and can be caused lots of things.
Some are listed below.
By batteries been left connected in boats where slight currents are drawn from the battery. These slight currents can be caused by not just items left on. They can be caused by wet terminals like those across GPS, sounder and radio plug terminals when they have been unplugged before the big tubbin' (wash) everybody gives their boat after an outing. The best way to solve this is to give all the terminal plugs a spray the same as you do with the motor internals all the time. Remove the moisture and give some protection is important..
Electrolysis can also be caused by moisture left in the boat itself if there are different materials used (such as aluminium and brass/copper), or the aluminium hull is not potentially bonded (ie all the aluminium is not joined together). That is why outboard motors now have those little wire traces jointing diiferent bits nowadays.
Do not confuse electrolysis with corrosion which can occur around the battery when it is left in the boat. This normally occurs when you use the good old lead/ acid battery. They sweat just like us and the acid vapour causes the corrosion.
If in doubt remove the battery.
My theory is if everything is clean and protected you don't have troubles, especially if there is no battery in the boat.
It is true, tooo many anodes do more harm then good. besides more bumps on the keel must make a lot of spray when you're motoring around on the water

BladeRunner
11-03-2005, 03:27 AM
Finga64
Excellent post . I too am in the electrical trade but obviously I didn’t explain the theory properly
What you covered is the same on my Yamaha motor those little bits of wire and a anode .

When I put a battery in the boat to run lights and other stuff after a while a white powder appeared on the floor of the hull. I was looking for sinkers under the floor which had fallen down there. They won’t help
It appeared to be electrolysis of some kind, mate said attach an anode to the hull . I brought one from a marine shop fitted it and the powder has gone and the boat is protected. As for moisture shore try to keep every component as dry as possible corrosion happens as finga64 said between copper terminals and in electronics.
Salt water is very conductive & corrosive .

BladeRunner

finga64
11-03-2005, 04:49 AM
Bladesrunner, did you find the sinkers ???

My theory on all corrosion/electrolysis/galvanic reactions/problems or what ever people call the white "cancer" is to fix the cause, not treat the problem (The same logic applies to any problem).
Any 2 dissimilar metals will cause an galvanic cell and cause corrosion (even stainless on aluminium to a degree).
In the case of salty water the second metal is in the water in the form of sodium
Salt water is made up of salt (NaCl2) and water (H2O).
Sodium (Na) is an alkali metal and therefore an aluminium boat, not washed 100% = sodium left behind in contact with aluminium (metal to metal).
Sodium + aluminium = corrosion and to make it worse alkalis are bad for corrosion as well (leave some washing powder in the tinny and see what happens).
I didn't bore everybody with chemical mumbo jumbo and electron transfer equations but if any body whats to know send me a message
Funnily enough the word alkali comes from an Arabic word meaning "ashes" (what does corroded aluminium look like)
Yeh, I'm a nerdy #:P sorry, but I can fish and weld as well #;D
In my dads tinny (70 model Quinny) I bonded all the ribs, dash, or any aluminium together with the good old stainless wire trace about 25 years ago and there is still no white powder.
I firmly believe in first find the problem, then fix the cause of the problem-problem solved. No need for remedies.
Cheers
P.S. I have fiberglass boats #;D

Kerry
11-03-2005, 06:11 AM
....I firmly believe in first find the problem, then fix the cause of the problem-problem solved. No need for remedies

And so say I, totally agree with that as many people while attempting or thinking they are fixing one problem can quite easily be creating an even bigger problem. Might not be immediately evident but hindsight can't fix a well evolved problem. Fix the cause not the result.

One other thing with alloy is that it is not pure either and will/does have traces of foreign metal, some internal, some external, which can come from all types of strange sources, some while in manufacturer, some by being handled, lifted, belted, cutting etc etc.

But put simply if a boat is wired correctly, battery maintained and housed properly then there really isn't too many issues with stray electrical in a tinnie but not to confuse this with dissimilar metal problems.

Cheers, Kerry.

finga64
11-03-2005, 06:48 AM
Dissimilar metals (remember salt is really a metal in the chemical sense) in an alkali or acid condition is called a galvanic cell (or battery) it is in these conditions that corrosion is caused, no matter what the metal you are talking about is.
Equi-potentential bonding is one way (and usually the easiest) to eliminate this as the electron transfer and is done through wires, not the boat. Stray currents are evident in boats, cars or any metal object and rust/corrosion is caused by these currents even if there is no battery near the car/boat, whatever.
That is why the old rivetted aluminium boats corroded fast. The salt sat in the rivet joins add a bit of moisure (out of the air) and hay presto and instant eveready battery.
Same reasoning tells us that old cars that sit in Cleveland rust quicker then old cars in Alice Springs and that is why steel that is under water doesn't corrode as fast as steel in a coastal area (the salty water acts as an equi-pential conductor when the object is under water)
I have measured potential differences (voltages) of up to 7.5 volts in a boat.
The same principle is why you sometimes get tingles from your taps in the shower especially if you stand on the drain grate and you have metal pipes and have some cuts in your hands. On one investigation I found a potential difference of 168 volts.
These galvanic voltages are sometimes high voltages but mostly very low currents (like a flat battery) that is why the corrosion can take a while to happen and the voltage doesn't kill you-mostly ;)
Kerry is quite correct in talking about impurities and something a lot of people wouldn't think about. That's why its important to really check your tinny before the warantee is over. Hopefully impurities are starting to play up and show by then
Good point Kerry ;D
Some things you just cannot fix if they're built into the aluminium or a bad design. #:-[ #:-/

quigs
26-03-2005, 05:36 AM
Ok I'm getting the understanding of the science of corrosion and galvanic reactions in boats, my question is.... Should the hull of the alloy boat be "bonded" to the Outboard in order to gain the protection of the least noble metal. ie the outboards annode? Or should it be insulated from the outboard via spacers, duralac etc? If its bonded dosent that mean thet the hull becomes an active earth in the system? Does that then encourage corrosion?

Kerry
26-03-2005, 06:08 AM
....If its bonded dosent that mean thet the hull becomes an active earth in the system? Does that then encourage corrosion?....

The battery -ve connects to the outboard (proper) and the outboard gets bolted to the hull, can't to much less than that.

The real problems can arise if the battery -ve is then specifically strapped to the hull (proper) and even worse if the hull is then used as an earth return, which is an absolute no no in both cases. Then things really start running round in circles.

Cheers, Kerry.

quigs
26-03-2005, 06:27 AM
Ok Kerry so have i got it right? dont insulate motor from hull so then the hull uses the anode on the outboard?

Kerry
26-03-2005, 04:58 PM
Ok Kerry so have i got it right? dont insulate motor from hull....

No, no point and in any case would be extremely difficult to do "properly"


....so then the hull uses the anode on the outboard?....

I'll leave that one up to those that make some of this black scientific stuff their profession as many outboards have more than 1 anode and in many cases it's the (secondary) trim tab anode that sees more action than what many assume to be the primary (mounting bracket) anode.

I've never replaced the main anode on ether engine in 15 years, where as the trim tab turn to cob webbing every few years.

Somehow I'd be worried if an outboard anode didn't show some reaction, sometime.

Cheers, Kerry.

quigs
27-03-2005, 03:25 AM
Thanks Kerry for afirming what I gleaned from my research.

Quigs

troy
27-03-2005, 05:08 AM
kerry
this has nothing to do with this post but as i am relatively new to computers how do place what other guys have said above your reply.
cheers troy

BladeRunner
27-03-2005, 08:16 AM
quigs
Glow in the dark stuff fellors/ Gals

Just an experiment why don’t you hook up the battery to the tinnie that way you will find all the anodes placed on the boat, they will glow in the dark .
Especially if it is earthed make shore your boat is in the water .

And if the boat is wired correctly this phenomenon dose not show at all
happy wiring
BladeRunner

Kerry
27-03-2005, 09:22 AM
kerry
this has nothing to do with this post but as i am relatively new to computers how do place what other guys have said above your reply.
cheers troy

Place what ever it is you want to quote between the word quote (within square barckets) and /quote (within square brackets)



place text here

For BOLD, Italics or underline (an others) simply highlight the text and hit the appropraite Add YABBC Tags B I U (above the smilies)

Cheers, Kerry.

Angelika koop
25-09-2008, 08:39 AM
If Boaties are looking for a solution to preventing electrolysis once and for all then I would suggest you investigate an electrolysis prevention system called SeaBis.

So far it turns out to be the only product that detects stray current, shows you a process to source and eliminate stray current and then provides a detector so that you can continue to monitor stray current and eliminate it immediately on detection.

Once all the stray current has been sourced and eliminated then t he boat stays stray current free and cannot be effected by marinas or neighboouring boats or any other stray current that might be hanging around.

When there is no stray current then there is no electrolysis. See for yourself at http://www.seabis.net

Hydrotherapy
25-09-2008, 09:49 PM
Kerry is 100% correct. Could not agree more.

I am also a sparky and i have a particular interest in galvanic corrosion and electrolysis, both of which occur in the boating world.

It's worth noting that the galvanic process can only occur within an electrolyte environment, salt water is an excellent electrolyte. In fact any water will conduct (even PURE water).

Good wiring, proper anodes and wash her down with fresh water and let her air dry is the best prevention.

In regard to motor isolation. There is a distinct difference between bonding and earthing. The electrons from the negative battery terminal will seek the shortest path to the pos terminal, they don't care if they have to go through your hull. Give them a good clean/short path via earth wires. Bonding on the other hand is crutial for proper anode operation.

Bond the motor, earth the accesories.

Ram-rod
26-09-2008, 12:22 AM
Mate told me I should never leave the battery in the boat as it causes severe electrolysis and will stuff the boat in no time at all. Is this true?
Struth there is some science coming out here. I just disconnect my battery (At the battery terminal) when the boat is not being used..

Courteby
26-09-2008, 04:37 PM
I use a battrey clamp attached to a electrical wire that runs out the side of the shed into the earth. I clamp the earth wire to the hull when boat is stored.

In short, with the isolator off and the earth wire attached, it has stopped the electrolysis which seemed to be taking effect on our boat which was 1 year old at the time. Its now 3 years old and shows only slight advancing electrolysis.

Works for us. (Probably all in my head) Cheers !:)

evo001
26-09-2008, 04:55 PM
This may be slightly off topic but has to do with electrolysis.

When you put your aluminium boat on top of your zinc plated mild steel trailer and connect tiedown chains and steel winch cables you also create an a potential corrosion problem.

I've put a multimeter in the circuit and read a potential of 5 volts.

Kind makes you think doesnt it.

Hydrotherapy
26-09-2008, 06:36 PM
Next time you are out in saltwater, prob the water around the boat with a multi meter (black to the hull, red in the water). You may get a surprise.

Rumor has it that salmon are attracted to it..........................