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Old 26-11-2012, 10:26   #1
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Brass Seacocks -

I recently went to a presentation by a surveyor. He was talking about construction problems and he said he constantly runs across dangerously corrosive brass seacocks installed by production boat builders. He says these materials were never used 20 years ago but are now common. Although there are acceptable brass alloys, specifically known as DZR (dezincification-resistant) and with the EN designation of CW602. He said those are fine and close to being as solid as bronze, but that more often he sees CW617N brass thru hulls and seacocks that because of their zinc content are subject to electrolysis. Apparently the law only requires the seacocks to meet the ISO standards (IS0 9093-1) and it says only that they should be of ‘a material which, within a service time of five years, does not display any defect that will impair tightness, strength or function.’

Who wants to buy a boat with below water fittings that may only have a life of only 5 years? Anyway, he didn't say who the "major production boat" companies are that are putting CW617N fittings on their boats. Does anyone know?

I am curious if those of you who have a relatively new boat know what kind of thru-hull and seacock you have....Its probably bronze, DZR brass CW602, Marlon possibly, or the more dangerous CW617. CW617N is the European designation for ordinary brass with a high zinc content, and according to this guy many Ball valves with this designation are used by boat makers now to save on the bronze cost. I would like to find out what companies he was talking about.
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Old 26-11-2012, 11:00   #2
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Re: Brass seacocks -

Pamlico,

This is a pretty well known issue with almost all production boats. I believe that all of the big three sailboats manufacturers use brass, and a good number of the power boat guys do as well. The reality is that bronze is much more expensive, and very few people even know what the difference is, so why should they spend thousands more on siliconized bronze instead of crap brass.

This is happening in a lot of places, not just thru hulls. More and more manufacturers are using 304 instead of 316 stainless parts, in large part because the price of 316 is orders of magnitude more than 304. Simply because the 304 is used in so many different applications, and 316 is a much more specialized metal.


The drivers of this are varied, but it used to be that good bronze wasn't that expensive. But with world copper prices shooting thru the roof prices on the bronze have skyrocketed. The same thing has happened with stainless, and the cost of chromium. As the alloying metals price goes up the resistant metals price goes up too, often faster than you might expect because of manufacturing concerns.
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Old 26-11-2012, 11:16   #3
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Re: Brass seacocks -

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This is happening in a lot of places, not just thru hulls. More and more manufacturers are using 304 instead of 316 stainless parts, in large part because the price of 316 is orders of magnitude more than 304. Simply because the 304 is used in so many different applications, and 316 is a much more specialized metal.
Stainless 316 is generally about 25% more expensive than Stainless 304. It isn't anywhere near the outrageous price of titanium.

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....But with world copper prices shooting thru the roof prices on the bronze have skyrocketed....
I don't understand the reason for the increases in copper prices. According to the Copper Development Association; "We're in no danger of running out of copper. Known worldwide resources of this important and valuable metal are estimated at nearly 5.8 trillion pounds of which only about 0.7 trillion (12%) have been mined throughout history.".
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Old 26-11-2012, 13:16   #4
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Re: Brass seacocks -

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Stainless 316 is generally about 25% more expensive than Stainless 304. It isn't anywhere near the outrageous price of titanium.



I don't understand the reason for the increases in copper prices. According to the Copper Development Association; "We're in no danger of running out of copper. Known worldwide resources of this important and valuable metal are estimated at nearly 5.8 trillion pounds of which only about 0.7 trillion (12%) have been mined throughout history.".
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Old 26-11-2012, 13:28   #5
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Re: Brass seacocks -

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Originally Posted by Stumble View Post
Pamlico,

This is a pretty well known issue with almost all production boats. I believe that all of the big three sailboats manufacturers use brass,

mmmm....not exactly . . . . agree that it is almost universal with the EUROPEAN production boat builders (including in their american factories), who are required to meet the CE standard is the of the '5 year lifespan' spec. This includes Beneteau and Jeanneau, etc, and even some of the more 'prestige' European brands.

It is NOT true for the American boat builders who follow ABYC - like Catalina, Hunter, etc.

I have been puzzled for years why the American brands don't point out this fundamental different in quality to their potential customers.

As to how much of a problem brass thru hulls actually is . . . it depends . . . on the 'hard service side' - there is a service bulletin that indicates the Moorings was having to replace their every two years. And in electrically active marinas it can be a very quick and serious problem. But on many boats it does not became an issue for 10-15 years - then I have seen several boats where the thru hulls would just snap off in your hand.

Its definitely something buyers should both factor in to price and resell value and inspect carefully for safety.
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Old 26-11-2012, 13:35   #6
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Re: Brass seacocks -

The EU sanctioning body decided that sea cocks only needed to last a decade or less and allowed European to use brass fittings. The lower end mfg. cheapened out and went with brass. Don't think it effected the few US builders that are left.

304 has traditionally been the alloy of choice for SS from the US production builders. Only recently has 316 become for US builders. Remember sitting in Papeete and noticing the Euro boats SS was all bright and shiney while US boats was tarnished and rust stained.
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Old 26-11-2012, 15:32   #7
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Re: Brass seacocks -

Anonymous,

The issue isn't world wide supply, there is plenty of copper in the ground. The problem is refining, smelting, fabricating, and environmental hurdles of getting new copper to market. Particularly China and India have been buying huge quantities of copper for electrical wire, and there just isn't enough to go around. Simple supply and demand curve.


Estar,

Thanks for that catch. There seems to have been a wholesale swap to brass fittings when the EU standard came out, and I just assumed that the US makers followed along with them. I was clearly wrong, and thanks for pointing that out to me.
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Old 26-11-2012, 15:42   #8
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Quote:
Originally Posted by Stumble
Anonymous,

The issue isn't world wide supply, there is plenty of copper in the ground. The problem is refining, smelting, fabricating, and environmental hurdles of getting new copper to market. Particularly China and India have been buying huge quantities of copper for electrical wire, and there just isn't enough to go around. Simple supply and demand curve.

Estar,

Thanks for that catch. There seems to have been a wholesale swap to brass fittings when the EU standard came out, and I just assumed that the US makers followed along with them. I was clearly wrong, and thanks for pointing that out to me.
It simply isn't the case that pure brass fittings are used in all EU production boats most I've seen are DZR. bronze is on the other hand quite rare. .. The other issue is that seacocks arnt in general falling out of such boats. I've seen plenty 10+ year boats whose underwater stuff is good. There seems to be far more stray current issues in 110v land then 230 land. I suspect the widespread use of RCBs is a major factor in the difference


The commission is modifying the RCD directive in respect of sea cocks so the position should improve.
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Old 26-11-2012, 17:06   #9
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Re: Brass seacocks -

Five years is not an acceptable lifespan for this kind of hardware. I'd say ten years is also too short.

What really worries me about this stuff, though, is that substandard materials often don't show many visible signs of failure until they suddenly give way. A hose bursts, and in the frenzy to stem the leak, you really slam the seacock handle over- snapping the whole thing off the hull. That's just not cool.

Brass (including the misnamed "manganese bronze" which is actually brass) just doesn't last in salt water. No amount of fiddling with policies and guidelines is going to change that. DZR brass works in theory, but it requires very careful control of the heat treatment and I'm not entirely sure if everyone's QA is up to that task. Plus, you now have arsenic in your through-hulls.
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Old 26-11-2012, 17:13   #10
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Re: Brass seacocks -

I with you Matt. I will always choose bronze. At least until we get the designs for titanium worked out
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Old 26-11-2012, 17:23   #11
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Re: Brass seacocks -

Quote:
Originally Posted by Stumble View Post
The issue isn't world wide supply, there is plenty of copper in the ground. The problem is refining, smelting, fabricating, and environmental hurdles of getting new copper to market. Particularly China and India have been buying huge quantities of copper for electrical wire, and there just isn't enough to go around. Simple supply and demand curve.
That is like saying that gasoline prices are based on supply and demand. This position ignores the fact the they are a traded commodity.

According to electricalsolutions.net.au:

"The London Metal Exchange is the world's leading commodity, futures and options exchange for non-ferrous metals. Their copper price index sets the benchmark for pricing and hedging for most of the world's copper transactions.

The volatility can be attributed to the actions of various fund managers. Institutional investors who invest our superannuation dollars constantly monitor futures and hedge markets, looking for places to invest our money for solid returns. For copper, they look at the forecast supply and demand figures, analysing the current and anticipated demand for copper, which determines their interest in futures markets ie, the potential future value of copper. Of course there has to be a link between the physical market where actual product is bought and sold and the anticipated demand in the future and the market's ability to satisfy that demand, in anticipation that the price will go up and generate a reasonable return on the invested super funds."
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Old 26-11-2012, 18:20   #12
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Re: Brass seacocks -

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l EU production boats. . . . most I've seen are DZR.
What EU production boats are you aware that use DZR?

Beneteau and Jeanneau do very clearly use (60/40, NOT DZR) brass. As do HR, Malo, X-yachts, & Dufour (many of these are using brass fittings made by Guidi in Italy).

Dufour initially claimed they were using DZR but when pressed (by a British magazine) why the fittings were not marked as dzr later admitted they were common brass. Hanse has claimed to be using dzr, but their fitting are also not marked as dzr, and those tested in two surveys were proven to be common brass.

There is a pretty decent website discussion of some of this at (he's a metallurgist and sailor) Brass and Bronze

As an aside, even the 'DZR' marked valves often have ordinary brass balls in them.
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Old 26-11-2012, 18:49   #13
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Re: Brass seacocks -

All my thruhulls and seacocks and shaft log are Groco, thirty-five years old. I recently bought some 1/4" silicon bronze lag screws to secure a customer's ronze washdown valve. Three lag screws cost more than the valve. Glad I spent the money I did thirty-five years ago. Better than gold futures.
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Old 26-11-2012, 18:49   #14
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Re: Brass seacocks -

All of the French built boats are using brass ball valves which can degrade rapidly in salt water but are not usually a problem here in the fresh water of the Great Lakes unless stray current gets involved.

Lets not call these things seacocks ... they are not. they are domestic plumbing valves on a throughull. Rarely will you see a flanged seacok on a French boat.

There is another problem with these valves that has not been mentioned yet. The throughulls are NPS (straight thread) and the domestic plumbing ball valves are NPT (tapered thread). They are a constant source of small leaks and the very act of threading the valve on to the throughull the thread on the throughull.

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Old 26-11-2012, 19:17   #15
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Re: Brass seacocks -

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All my thruhulls and seacocks and shaft log are Groco, thirty-five years old. I recently bought some 1/4" silicon bronze lag screws to secure a customer's ronze washdown valve. Three lag screws cost more than the valve. Glad I spent the money I did thirty-five years ago. Better than gold futures.
I was shocked when I had to pay $9+ each for a pair of 3/4"-10 tpi bronze nuts to go on a quadrant/steering arm.
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