Galvanic Corrosion

[fudd]

Morning all. I've been advised to install a galvanic isolator rather than an isolation transformer to protect against airborne waves of some sort. It was explained to me but I lost it half way through the conversation. I just want what is best for us, I'm not a fashion victim so I don't want what is the newest and blingest piece of equipment. I have read up about them and it seems to me that an isolation transformer is easier to get on with but more difficult to install but an isolator needs to have an eye kept on it to make sure it's still protecting the hull. Cost isn't an issue as the transformer I had my eye on was an Airlink product. It's dearer than the other option but so is my hull. Ideas or advice warmly welcomed. SteveP

[RLWP]

Airborne waves???

 

They're having you on

 

Richard

[NB Willawaw]

Isolation Transformer !!

 

Morning all. I've been advised to install a galvanic isolator rather than an isolation transformer to protect against airborne waves of some sort. It was explained to me but I lost it half way through the conversation. I just want what is best for us, I'm not a fashion victim so I don't want what is the newest and blingest piece of equipment. I have read up about them and it seems to me that an isolation transformer is easier to get on with but more difficult to install but an isolator needs to have an eye kept on it to make sure it's still protecting the hull. Cost isn't an issue as the transformer I had my eye on was an Airlink product. It's dearer than the other option but so is my hull. Ideas or advice warmly welcomed. SteveP

[Nickhlx]

Airborne waves???

 

They're having you on

 

Richard

 

Yes - that was my immediate thought - perhaps they are not sure what they are talking about or have a surplus stock of isolators..

 

As they are not that expensive ( Isolators) why not fit both ?

 

Are you in a "high risk" environment ?

 

Nick

[fudd]

Airborne waves???

 

They're having you on

 

Richard

 

He might not have said waves but it was definitely airborne. I think he mentioned " suppression" as well. I'm a carpenter by trade. Need I say more!

[AidanLincs]

I'm sure that wiser heads than I will be along shortly.

 

As far as I am aware, the ONLY situation where a galvanic isolator can possibly be of any benefit is where you have shoreline power and are moored near other boats: i.e. in a marina.

 

The airborne waves of which you speak can be easily blocked by wearing a lead helmet.

[Gibbo]

The airborne waves of which you speak can be easily blocked by wearing a lead helmet.

 

Don't be ridiculous. There's no need for lead. A tin foil hat is perfectly adequate and much lighter.

[fudd]

Yes - that was my immediate thought - perhaps they are not sure what they are talking about or have a surplus stock of isolators..

 

As they are not that expensive ( Isolators) why not fit both ?

 

Are you in a "high risk" environment ?

 

Nick

 

Not particularly Nick. But the survey said there was some corrosion to the baseplate that will need looking at. Somewhere in the region of +- 3mm.

I'm not sure about both. Has anyone else done it?

[blackrose]

Morning all. I've been advised to install a galvanic isolator rather than an isolation transformer to protect against airborne waves of some sort. It was explained to me but I lost it half way through the conversation. I just want what is best for us, I'm not a fashion victim so I don't want what is the newest and blingest piece of equipment. I have read up about them and it seems to me that an isolation transformer is easier to get on with but more difficult to install but an isolator needs to have an eye kept on it to make sure it's still protecting the hull. Cost isn't an issue as the transformer I had my eye on was an Airlink product. It's dearer than the other option but so is my hull. Ideas or advice warmly welcomed. SteveP

 

As far as I'm aware the Airlink is an isolation transformer, not a galvanic isolator. An IT is more expensive, bigger and not quite as simple to fit as a GI, but an IT is the superior article. If a good spec GI is working properly then both the GI and IT will do exactly the same job in blocking galvanic currents, so it just depends how much you want to spend.

 

What neither device will do is block airborne currents. For that you need an airborne current blocker. Ask about them at your local chandlers.

[fudd]

I'm sure that wiser heads than I will be along shortly.

 

As far as I am aware, the ONLY situation where a galvanic isolator can possibly be of any benefit is where you have shoreline power and are moored near other boats: i.e. in a marina.

 

We are close to other boats and we are on a shoreline.

The airborne waves of which you speak can be easily blocked by wearing a lead helmet.

[RLWP]

 

What neither device will do is block airborne currents. For that you need an airborne current blocker. Ask about them at your local chandlers.

 

[fudd]

As far as I'm aware the Airlink is an isolation transformer, not a galvanic isolator. An IT is more expensive, bigger and not quite as simple to fit as a GI, but an IT is the superior article. If a good spec GI is working properly then both the GI and IT will do exactly the same job in blocking galvanic currents, so it just depends how much you want to spend.

 

What neither device will do is block airborne currents. For that you need an airborne current blocker. Ask about them at your local chandlers.

 

Yeah yeah yeah. Don't tell me I've been had?

[RLWP]

Yeah yeah yeah. Don't tell me I've been had?

 

You've been had

 

Fit the isolation transformer

 

Richard

[blackrose]

As far as I am aware, the ONLY situation where a galvanic isolator can possibly be of any benefit is where you have shoreline power and are moored near other boats: i.e. in a marina.

 

Yes, if you're not on shore power then forget about it. But you don't necessarily need to be on shore power and moored near other boats to benefit from galvanic isolator or isolation transformer.

Edited July 24, 2012 by blackrose

[Nickhlx]

Not particularly Nick. But the survey said there was some corrosion to the baseplate that will need looking at. Somewhere in the region of +- 3mm.

I'm not sure about both. Has anyone else done it?

 

Crikey !

 

About 3mm sounds potentially serious to me, especially on an older boat with a hull that is only perhaps 6 mm thick to start with...

 

Is it really electrolytic corrosion, caused by e.g. being hooked up to a shoreline next to a faulty installation.. or is it "natural" wear and tear" over the years / decades ?

 

Whilst having both is certainly overkill, and the isolation transformer (correctly used and sited) would be the preferred single item to use, I can't see that having both

would be disadvantageous other than to the bank account ( Gibbo will confirm) and you indicate that funds are not too tight...

 

Nick

Edited July 24, 2012 by Nickhlx

[fudd]

Yeah yeah yeah. Don't tell me I've been had?

 

Thinking about it, he did say something about a mate of his that runs his house lights off the airborne induction.

I think I've been mugged.

[blackrose]

Whilst having both is certainly overkill, and the isolation transformer (correctly used and sited) would be the preferred single item to use, I can't see that having both

would be disadvantageous other than to the bank account ( Gibbo will confirm) and you indicate that funds are not too tight...

 

Nick

 

Having both is a waste of time I'm sure.

[Nickhlx]

Having both is a waste of time I'm sure.

 

I agree, but if funds permit and there's no technical reason not to...

It would give a backup for the IT if that went TU

 

 

Nick

[RLWP]

I agree, but if funds permit and there's no technical reason not to...

It would give a backup for the IT if that went TU

 

 

Nick

 

Would it? If the failure mode was to somehow connect the two sets of windings I guess it might. Far more likely that the IT would go open circuit on one side though, isn't it?

 

Richard

[AidanLincs]

Don't be ridiculous. There's no need for lead. A tin foil hat is perfectly adequate and much lighter.

 

There was some research done at Stanford University (no, really!) a few years ago that proved conclusively that a tinfoil hat actually acts as a receiver!

[RLWP]

There was some research done at Stanford University (no, really!) a few years ago that proved conclusively that a tinfoil hat actually acts as a receiver!

 

Parabolic reflector innit. Focuses the waves onto your pituitary gland

 

Richard

[fudd]

Crikey !

 

About 3mm sounds potentially serious to me, especially on an older boat with a hull that is only perhaps 6 mm thick to start with...

 

Is it really electrolytic corrosion, caused by e.g. being hooked up to a shoreline next to a faulty installation.. or is it "natural" wear and tear" over the years / decades ?

 

Whilst having both is certainly overkill, and the isolation transformer (correctly used and sited) would be the preferred single item to use, I can't see that having both

would be disadvantageous other than to the bank account ( Gibbo will confirm) and you indicate that funds are not too tight...

 

Nick

 

It's a 10-6-4 hull so we aren't doing too bad.

 

Crikey !

 

About 3mm sounds potentially serious to me, especially on an older boat with a hull that is only perhaps 6 mm thick to start with...

 

Is it really electrolytic corrosion, caused by e.g. being hooked up to a shoreline next to a faulty installation.. or is it "natural" wear and tear" over the years / decades ?

 

Whilst having both is certainly overkill, and the isolation transformer (correctly used and sited) would be the preferred single item to use, I can't see that having both

would be disadvantageous other than to the bank account ( Gibbo will confirm) and you indicate that funds are not too tight...

 

Nick

 

The survey said its corrosion at the furthest point from the anodes. That is in the middle of the boat. I think 3mm corrosion is not too much to worry about but I want it to stop there.

[Nickhlx]

It's a 10-6-4 hull so we aren't doing too bad.

 

 

 

The survey said its corrosion at the furthest point from the anodes. That is in the middle of the boat. I think 3mm corrosion is not too much to worry about but I want it to stop there.

 

Agree, as its a 10mm hull... perhaps next time the boat is out, get the bigger / deeper holes filled with weld ?

 

And maybe fit more anodes if its possible / practical to do so ?

 

Our 10mm hull is now approaching 4 years in the water and anodes haven't corroded much at all....

 

( not sure about the hull though )

 

 

 

Nick

Edited July 24, 2012 by Nickhlx

[Robbo]

Morning all. I've been advised to install a galvanic isolator rather than an isolation transformer to protect against airborne waves of some sort. It was explained to me but I lost it half way through the conversation. I just want what is best for us, I'm not a fashion victim so I don't want what is the newest and blingest piece of equipment. I have read up about them and it seems to me that an isolation transformer is easier to get on with but more difficult to install but an isolator needs to have an eye kept on it to make sure it's still protecting the hull. Cost isn't an issue as the transformer I had my eye on was an Airlink product. It's dearer than the other option but so is my hull. Ideas or advice warmly welcomed. SteveP

 

An IT is 3 times harder to fit than a GI, basically there's 6 connections where the GI has 2.

 

The GI you break the earth, so 1 connection from shore and 1 connection to the boat.

Where the IT you break the earth, live and neutral so 3 connections to fit shore and boat side.

 

In seriousness, the IT is heaver and more bulky than a GI, 25Kg vs a few (if that), that's the only real installation issue.

[eightpot]

Parabolic reflector innit. Focuses the waves onto your pituitary glandRichard

 

This reminds me of the trick with my cars keyfob if I'm too far out of range to lock the doors. Hold said key up to side of head and use my noggin as a booster aerial. I don't think I've fried *too* many brain cells, well not any important ones.

 

Agree, as its a 10mm hull... perhaps next time the boat is out, get the bigger / deeper holes filled with weld ?And maybe fit more anodes if its possible / practical to do so ?Our 10mm hull is now approaching 4 years in the water and anodes haven't corroded much at all.... ( not sure about the hull though )Nick

My 8mm hull is approaching 23 years in the gloop and had lost 2.1mm at the time of its last survey. I fitted an airlink IT and stopped worrying. Moreso when my marina manager popped a letter through my door informing that stray current from a boat was detected by the on onsite engineer and all moorers were urged to get their electrical installations checked and fit to a GI. On checking my anodes I had fitted the last time my tub was blacked and seeing *no* erosion, I was thankful I'd stretched to the expense of an IT. 'Twas easy to DIY fit too.