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colemj · 08-11-2014, 14:04

Quote:

Originally Posted by sailorboy1

stainless anchors ......................... ooh shiny

is there more to say about it really?

Having once owned a SS anchor with SS chain, the mud just slides off it and it comes up clean. If one anchored in muddy areas a lot (Chesapeake, for example), these are really nice things to have. SS chain also collapses very well into an anchor locker and never piles up.

Plus, magic stuff are done to them to make them super strong and super special. Don't bother googling for that - it's a secret.

Mark

**Dockhead** · 08-11-2014, 14:09

Two anchors. 45kg Spade primary, large Fortress kedge. Fortress at all times ready in the anchor locker.

I used to have a 25kg Delta as a spare, but gave it away. Silly to drag around 25kg of pure dead weight.

The Fortress gets used. Deployed off the stern when Baltic mooring bows to.

It's also instantly deployable in case of any emergency.

rwidman · 08-11-2014, 15:15

Quote:

Originally Posted by Kenomac

............. One fact is for sure... A galvanized anchor WILL eventually rust and corrode.................

Of course it will. Another fact that's for sure... We will all die and turn to dust. The question is; which will occur first?

Stumble · 08-11-2014, 17:04

Quote:

Originally Posted by colemj

Yes, this is correct and a very good feature of stainless anchors. To put it in perspective, however, our galvanized Rocna is 7 years old and has been in full time use. The first 1.5" of the tip lost its galvanizing last year and is starting to rust a bit. I suspect in another 4-5 years, the whole thing will start to rust.

Our galvanized Rocna anchor costs $570. The SS version costs $3,000. So I can buy 5 galvanized anchors for less money than a single SS one. This should last me 55 years.

If I wanted an anchor to last more than 55 years, then the SS version would be a good deal indeed.

Conflating SS use in fasteners with that in anchors is just silly. How often do you even see your anchor? Ours is buried in the bottom 90% of the time - on deck only for passages, where it doesn't cause any staining or damage to fittings from rust expansion.

BTW, are you also using SS chain?

Mark

My advice is to go with titanium G5 anchors. The company i used to work for made one for the owners boat. Same strength as steel, weight like aluminium, cost... Well it cost like titanium.

About the same size as a 35kg Ronca, cost something like $10,000. But it was guaranteed for 100 years.

model 10 · 08-11-2014, 17:46

Quote:

Originally Posted by colemj

Plus, magic stuff are done to them to make them super strong and super special. Don't bother googling for that - it's a secret.

Mark

That's pretty funny. Sometimes I feel like i can know as much about some simple things as some "real metallurgist" just by going to google. Those guy's should not publish if some yacht owners want it to seem so esoteric. It's not above the understanding of humble sailors who can read and do a simple search.

Kenomac · 08-11-2014, 20:57

Figure it out yourselves, you guys obviously know best using just a Google search.

poiu · 09-11-2014, 05:09

Quote:

Originally Posted by Kenomac

Poiu,

Broken bolts and welds are an entirely different issue caused mostly by improperly treated stainless, followed by oxygen deprivation. Or in the case of your weld... A bad weld improperly treated. A stainless steel anchor properly formed, welded, then chemically treated with nitric acid won't suffer the same fate and will have high strength and resistance to rust and failure. Information that can not be found on a chart or Google search.

Like I stated earlier, not all stainless is created equal, how it's treated and constructed has to be taken into consideration... Not just the yield strength of a piece of bar when comparing to steel. One fact is for sure... A galvanized anchor WILL eventually rust and corrode.

Question: When those 316 bolts failed on your boat, did you replace them with galvanized? No you most certainly did not.... you went with stainless for it's rust and corrosion resistance properties.

I don't think the treatment of the bolts is an issue. There would be stress corrosion cracking regardless of the treatments you describe. The stresses that create the problem arise mainly post manufacture. The nitric acid treatment you mention is not used much now as it doesn't do a lot. What does work is polishing, even better, electro-polishing. That helps your anchor look good and to reduce pitting problems. It does little for stress corrosion.

Also, oxygen deprivation is not an issue with my failures. I only gave examples of SCC. Not crevice corrosion. The weld may have been poor skill or technique.

You may be lucky with you anchor. 316 is a beautiful material and if you don't stress it and if you don't bury it in mud with no O2 for a long time and if the welds were done carefully, it should serve you well. I wouldn't take these risks though.

With regard to the OP. I have two a main Rocna and a Fortress. The second is needed for backup, for rare kedge use and rare twin anchoring. So I don't think one enough. If two is enough, is the question I am less sure about.

rwidman · 09-11-2014, 06:08

Quote:

Originally Posted by Stumble

My advice is to go with titanium G5 anchors. The company i used to work for made one for the owners boat. Same strength as steel, weight like aluminium, cost... Well it cost like titanium.

About the same size as a 35kg Ronca, cost something like $10,000. But it was guaranteed for 100 years.

Was it guaranteed against loss? I would think the reason most people buy replacement anchors is that they got them hung up on the bottom and had to cut them loose, not that they broke.

rwidman · 09-11-2014, 06:11

Quote:

Originally Posted by colemj

............. our galvanized Rocna is 7 years old and has been in full time use. The first 1.5" of the tip lost its galvanizing last year and is starting to rust a bit. I suspect in another 4-5 years, the whole thing will start to rust...............

You can have it regalvanized. And you can do it over and over again.

colemj · 09-11-2014, 06:19

Quote:

Originally Posted by rwidman

You can have it regalvanized. And you can do it over and over again.

Yes, I know that but was making a point using the worse possible case. Regalvanizing just makes that point more so.

However, regalvanizing of something this small isn't always easy to find, some of it is not good, and often times the cost is 50% or more of a new anchor.

And I couldn't find any info on google about regalvanizing…

Mark

Randyonr3 · 09-11-2014, 06:53

Quote:

Originally Posted by colemj

Yes, I know that but was making a point using the worse possible case. Regalvanizing just makes that point more so.

However, regalvanizing of something this small isn't always easy to find, some of it is not good, and often times the cost is 50% or more of a new anchor.

And I couldn't find any info on google about regalvanizing…

Mark

I just had a conversation with a company in Oakland California about re-galvanizing my anchors.. His quote was any order has a minamum of $125,00 or about somewhere around $6.00 per pound.. He said a 45 lb anchor would be about 3 to 4 pounds.. so He said to get all you have and bring them in.. as its cheeper by the lb........ 4 anchors would have about 20 to 25 lbs X 6 or $150.00 ... not bad for 4 anchors..............

rwidman · 09-11-2014, 07:12

You can buy spray galvanizing paint at the home center. It won't hold up like hot dip galvanizing but You can clean off the rust and spray the anchor from time to time.

model 10 · 09-11-2014, 07:13

Quote:

Originally Posted by Randyonr3

I just had a conversation with a company in Oakland California about re-galvanizing my anchors.. His quote was any order has a minamum of $125,00 or about somewhere around $6.00 per pound.. He said a 45 lb anchor would be about 3 to 4 pounds.. so He said to get all you have and bring them in.. as its cheeper by the lb........ 4 anchors would have about 20 to 25 lbs X 6 or $150.00 ... not bad for 4 anchors..............

I had our anchor done there. They must use a light load in their G process as it started to wear off pretty soon. From my experience with that shop, I would want to know what I was going to get before I ever did an anchor anywhere again. It was almost a waste of money as the original G was not that that bad compared to their re-G after a year.
From what I understand, you want something like a #90 or a 60 coating at least. A #90 will heal the bare spots for some time.

colemj · 09-11-2014, 07:49

Most of the galvanizing being done in the US now is pretty poor compared to that in the past. Environmental regulations changed their processes.

Shipping our anchor to Oakland from Panama would add a bit to the cost…

Just to be clear, we don't currently need regalvanization. Just the very tip is rusty. I cleaned that up to shiny metal, sprayed it with galvanizing paint, and it lasted two anchorings in sand before the paint was removed.

Mark