Some Kind of Current Corrosion

[Phil Ambrose]

I have a Safeshore Marine G.I and it claims to work for both AC and DC, the monitor has warning LEDs for both AC leakage and for DC leakage.

So I can only suppose that even if you have no AC onboard it will take care of stray DC current floating about. Their website may well throw some light on this.

Phil

[RLWP]

I'm still not going to get a circuit going with the local piling - I don't have a DC shoreline either

 

Richard

[Traveller]

Thanks Phil

[Mark James]

Hi, thanks for all of your responses. In answer:

 

- Mark99, yes, we had anodes and they were shot to sherry when we took the boat out - but then it had been 8 years. We doubled up this time round and will look again next summer. We have ordered some new fenders (we never bothered for about 2 years as didn't mind the (minimal) bumping) - not realising we had opened ourself up to this!

- thanks for the link, Catweasel. Also, yes, it's a car type aerial (that has never tuned properly), and i'm taking it out pronto. We have a wind-up radio that works fine anyway.

- we haven't checked the voltage differential between the bank and hull, but the surveyor recommended an earth strap to equalise this. However, someone else said that that would guarantee we were part of the circuit.

- And bacteria!? Jeez. I'm ringing Brian Cox tomorrow...

 

Thanks again for your help.

[Timleech]

Does your boat sit in mud on your mooring?

 

Tim

[PhilR]

Pitting is due to the chemical variance in the steel used to construct your hull. Famousely, the reclaimed steel (from gasometers?) used by Piper was the purest available.

 

Alan

 

I thought it was just Sam Springer who, allegedly, used gasometer plate. Was it David and/or Simon Piper who also used the same? or is that heresay?

[Phil Ambrose]

I'm still not going to get a circuit going with the local piling - I don't have a DC shoreline either

 

Richard

Does anybody have a DC shoreline?

Phil

[RLWP]

Does anybody have a DC shoreline?

Phil

 

Not to my knowledge, you never know though...

 

Richard

[Sabcat]

Thomas Edison?

[RLWP]

Thomas Edison?

 

Clever!

 

Richard

[Detling]

Does your boat sit in mud on your mooring?

 

Tim

I agree I think the OP is suspecting the wrong cause of his pitting, he has no shore power to create a electrolysis problem and that is highly unlikely to attack only a few places on the base plate and not the waterline which is the usual target after the prop of course. More likely in my opinion is some physical abrasion caused by a brick or steel rod stuck in the mud at his mooring.

[ditchcrawler]

Does anybody have a DC shoreline?

Phil

There use to be one on our old mooring. It was a large wind generator on top of a pylon structure.

[wandering snail]

But what accounts for the silver pitting? Interested as this is what we've found on this liftout and we do seem to have a 12v leakage the cause of which so far we havn't established. Worried about putting Snail back in the water Monday but this boatyard's sooo expensive it's got to be done.

Edited September 26, 2014 by wandering snail

[smileypete]

Depends whether the pits are seen to be open, or covered in rust when the boat is slipped.

 

Also being in a marina/basin or close by other boats could make a difference.

 

cheers, Pete.

~smpt~

[wandering snail]

Depends whether the pits are seen to be open, or covered in rust when the boat is slipped.

 

Also being in a marina/basin or close by other boats could make a difference.

 

cheers, Pete.

~smpt~

When it came out it looked surprisingly good. After jet washing there it all was, silver on the sides, orange rusty on Snail's bottom which resembled lunar landscape.

[RLWP]

When it came out it looked surprisingly good. After jet washing there it all was, silver on the sides, orange rusty on Snail's bottom which resembled lunar landscape.

 

Yep - I wasn't joking when I posted that bacteria link you know. Bright, silver pits full of rusty slime?

 

Richard