Boat adverts - sacrificial anodes

[mark99]

bottom so exposed to more O2.

 

Exposed to electrolye (canal water) hence connecting the galvanic cell would be the main concern.

[Jim Riley]

 

Exposed to electrolye (canal water) hence connecting the galvanic cell would be the main concern.

yes, but bottoms aren't blacked because they are sitting in deeper water and less O2 afaik, mine is often shallow or just wet, not dried out completely.

[mark99]

yes, but bottoms aren't blacked because they are sitting in deeper water and less O2 afaik, mine is often shallow or just wet, not dried out completely.

 

No. Bottoms are not generally blacked because it scrapes off very quickly and hard to access practically.

 

In order to compensate for pitting, they (bottoms) are made thicker.

 

If there was little O2 how come fish don't have an issue swimming under boats?

 

Agree however there is additional corrosion at the waterline where the air meets the water.

Edited July 23, 2015 by mark99

[Theo]

I don't understand why that is of concern..?

 

The job of the anodes is to dissolve.....

They do that so that you boat doesn't dissolve...

All anodes dissolve over time.

 

You inspect them when you take the boat out of the water for blacking...

That is the best time to replace them should they be getting a 'bit low'.

It is easier than trying to weld new ones underwater.. on top of blacking.

 

We don't replace our anodes. We add the new ones beside them so that we get the last little bit of use from them.

 

N

[system 4-50]

I have two anodes. I have explained the situation carefully to them and now I'm hoping for some baby anodes.

[Jim Riley]

I have two anodes. I have explained the situation carefully to them and now I'm hoping for some baby anodes.

I hope you have galvanised them into action.

[MtB]

I have two anodes. I have explained the situation carefully to them and now I'm hoping for some baby anodes.

 

 

Anodettes, they are called.

[blackrose]

When I see an oldish boat that proudly advertises it's been recently blacked and had 4 new sacrificial anodes fitted, am I alone in suspecting that it might be a case of shutting the stable door...?

I don't understand your point. You'd rather the old blacking was flaking off with rust along the waterline and it had old anodes or no anodes fitted?

 

The new blacking and presence of new anodes are neither here nor there and can tell you nothing either way. Only a hull survey will indicate the hull condition.

[DHutch]

Bottoms are not blacked mainly for access, maybe also as you can't see it, we black ours and very little actually does get scrapped off.

 

 

Daniel

[boathunter]

I don't understand your point. You'd rather the old blacking was flaking off with rust along the waterline and it had old anodes or no anodes fitted?

 

The new blacking and presence of new anodes are neither here nor there and can tell you nothing either way. Only a hull survey will indicate the hull condition.

Yes, I would rather see it how it was before they decided to sell it, rather than after a possiblepre-sale cover-up.

Edited July 24, 2015 by boathunter

[John Williamson 1955]

I bought my boat while it was on the side, and hadn't been blacked for quite a while. I saw that it would need overplating at some stage, which was taken account of in the price.

 

I looked at the hull in the dry dock after it had been blacked earlier this year, and it still looked as though it would need overplating at some point in the future, but the corrosion and pitting were covered in paint. Two coats of blacking didn't hide the problems. A survey at this point would confirm what I could see. If I was worried about the blacking covering problems, then I'd look at other indicators of the way the boat had been looked after. Has the interior of the weed hatch been blacked, too? Are there dents in the hull or cabin top, is the engine clean, and if so, is it suspiciously clean, as if all the oil has just been cleaned off to hide the leaks?Is the interior in a reasonable state of repair, and so on. If the rest of the boat passed inspection, then I'd look hard at the hull, but new anodes and fresh blacking don't automatically mean a cover-up. They're as likely to show a careful owner, possibly trying to get the best price for the boat.