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Dirt Free
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Really? They, Jeanneau,used brass for thru-hulls back in 2000?
Absolutely ! Also Beneteau, Hanse, Bavaria, Dufour.

What makes you think they stopped this practice in 2000 ?

Take a look at a few articles on this page
 

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A decade ago we wanted to add a thru-hull and started trying to dig out details from basically all the suppliers in the US as to what their yellow thru-hulls were. And it turns out that "brass" and "bronze" overlap in alloys, so what one foundry calls "brass" is exactly the same as what another calls "bronze". And then at least one top name simply refuses to say what their "bronze" alloy actually is.

No, you should use brass on a boat, but yes, there are in fact "marine brass" alloys that can legitimately be used and called "bronze".

We gave up and went with genuine Marelon.
 

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No, you should use brass on a boat, but yes, there are in fact "marine brass" alloys that can legitimately be used and called "bronze".

We gave up and went with genuine Marelon.

Gentle disclaimer .... The metallurgy gets a little complicated so my opinions have been simplified for the purpose of this forum ....

This is incorrect , Brass is brass whether you call it plated brass, Naval bronze or admiraly bronze. These are largely marketing misnomers. True brass is defined by zinc content and the previously mentioned types have between 20% -39% zinc .... these are not bronze's

Various types of bronze's may have small amounts of zinc however the types preferred for marine use will have zero or close to it.

The issue with brasses is the "Dezincification" cause by galavaic corrosion. Think of it this way your "zincs" (anodes) are designed to waste by giving up electrons to more cathodic metals ..... Do you really want your brass thoughulls giving up electrons and wasting away like your zincs.

This whole brass throughull/seacock mess was caused by the CE standards stating that throughulls and seacocks should last 5 years. So what did Jeanneau, Beneteau et al do .... they bought the cheapest materials that would meet the standard :eek

These same builders saved even more money in many cases by fitting NPT valves on NPS throughulls ... Shocking idiocy !

Suggest you Google "dezincification, brass seacocks, NPT, NPS" lot and lots of stuff from legitimate authorities on this issue. Also some terrific photos of this stupidity on Compass Marine website (a frequent poster here).

Just to get you started read one of Paul Stevens articles in Yachting Monthly

PS. I am a Certified Corrosion Analyst and I believe this is verging on criminal.
 

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Boatpoker, the Blake seacock is a DZR brass that can be used for seacocks but I don't know of any other valve makers that use DZR brass for their valves. I was corrected by a metallurgist on saying all brass is a no go for the reason you sight.

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boatpoker-
I don't disagree with you, and don't need to google it. I went through all that and when the most respected names in the industry (US or otherwise) all played "he went that-a-away" like the three stooges used to, pointing to different names and alloys and contradicting each other AND metallurgy references, that's when I said **** this all, we're going plastic. Because a good glass filled nylon, kept below the waterline, will not take UV damage, will not corrode, will not de-zinc, and if it is in a place when gorillas and flying batteries can't land on it, it will be plenty sturdy enough. Not to mention cheaper.

Now, for you to suddenly reveal that a commercial mass-market boat builder would dare to cut corners and "build it to a price", that's just shocking. Really shocking. Next you'll be trying to convince me that they use stainless instead of titanium just to shave costs and keep the prices down. (We all know, stainless is shinier and shiny shiny pretty pretty is what really counts!)

I wonder, with online machine shops and CAD/CAM and all, what it would cost to either print or carve some truly durable titanium thru-hulls. You know, perfect xmas gifts for the racing, or fast cruising, set. And whether just any old titanium alloy would do?
 

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Boatpoker, the Blake seacock is a DZR brass that can be used for seacocks but I don't know of any other valve makers that use DZR brass for their valves. I was corrected by a metallurgist on saying all brass is a no go for the reason you sight.

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DZR (DeZincification Resistant brass) is a better quality brass alloy witha lower zinc content than normal brass with a couple of other metals thrown in and will do the job but not for as long as a good quality bronze.

There is still a bit of a crap shoot even buying brand name bronze Groco who had a great product and reputation for decades screwed up badly some years ago when theY switched production to China and did not supervise closely enough ..... result a huge recall. Don't trust Chinese metallurgy :)

As to Marelon .... yes, I have no problem with sizes 1.5" and over but the smaller ones give me the creeps. In a survey I used to put my foot on seacocks and apply a little pressure as they are supposed to handle up to 500lbs. lateral force. Let me just say that I learned the hard way that the smaller Marelon units were not up to the 500lb. standard.
 

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Bronze is a difficult material to pour (stringy), brass and stainless pour easily. No surprise manufacturers don't want to pour it.
 

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The big US manufacturers of seacocks & thru-hull fittings use 85-5-5-5 bronze almost exclusively. It has been the go-to bronze for seacocks as far back as the 1930's. I have many 85-5-5-5 seacocks out there beyond 50 years old. This list of manufacturers using 85-5-5-5 includes Groco, Apollo/Conbraco, Spartan, Buck-Algonquin and even defunct manufacturers such as Wilcocx-Crittenden... This is a far superior bronze than what the ISO/RCD builders use...
 

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Bronze is a difficult material to pour (stringy), brass and stainless pour easily. No surprise manufacturers don't want to pour it.
Ditto ... 'gas' bubble pockets/blow-outs too, unless the inlet/outlet 'sprues' of the mold are engineered to 'perfect'. Most 'true' bronzes are very difficult to machine (re. threads, etc.). But that is all ancient metallurgy.

BRASSES THAT ARE NOT SUBJECT TO DE-ZINCING.
Just like true-bronzes that are formulated without tin such as NickelAluminum Bronze, there are various available forms of BRASS, with zinc, that are anti-de-zincable (DZR or DR) brasses that are alloyed with 'transitional metals' such as Tellurium, Selenium, Tantalum, Niobium, Arsenic, etc. that changes the entire molecular (grain) structure which in turn inactivates and prevents the de-zinc-ability of the brass. These formulations and 'sequences' were closely held proprietary secrets. Its going to take a very long time for asian foundries to recover them; hence, the current problem of zinc loss from asian produced DRZ brass. These DZR alloys were originally discovered/formulated in the ~1950s-1960s for critical navy, aerospace and chemical engineering applications. Their current usage is quite widespread, despite the almost total forced collapse of the US 'red metals' industry and other domestic 'foundry' activities.
Here's a brief technical explanation of how these 'de-zincing' BRASSES are formulated: http://www.jomarvalve.com/docs/lit-jv-dzr.pdf

Here's a bronze without tin and without the typical trace zinc that aids 'machinability' ... I worked for of the original discoverers of this alloy at that time as a student intern bench chemist (at Phila. Bronze & Brass Corp. / AMCO Metals): Alloy: C95500 Nickel Aluminum Bronze - Concast Metals
 

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Boatpoker-
For the main engine water intake, that's often someplace (like in the bottom of a laz) where someone or something might step on it. But for "that *damned thruhull" under the forward washbasin that you have to secure for the head intake"...Regardless of size, you might want it is extremely resistant to being found by a 500# gorilla. Or even a clever capuchin monkey.(G)
All these technical details of "newer" alloys are the reasons that I got allergic to hearing the terms "brass" and "bronze" in any marine setting. Even ten years ago, they were being tossed around and the big guys were insisting everything was a Trade Secret. Which doesn't really impress those of us who have seen things like analytical labs. Used to be a properly timed pizza and six-pack could get you a fast analysis of almost anything in any college chem lab. So...
Brass? Bronze? Might as well say the boat is made of "plastic" and the spars are made of "wood". They're all the same, and well-defined, too. Right? (G)
 

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The big US manufacturers of seacocks & thru-hull fittings use 85-5-5-5 bronze almost exclusively. It has been the go-to bronze for seacocks as far back as the 1930's. I have many 85-5-5-5 seacocks out there beyond 50 years old. This list of manufacturers using 85-5-5-5 includes Groco, Apollo/Conbraco, Spartan, Buck-Algonquin and even defunct manufacturers such as Wilcocx-Crittenden... This is a far superior bronze than what the ISO/RCD builders use...
Yes, it was the go to. but do you know what 85 triple 5 means? the last 5 means it contains on average 5% Zn. the newer DZR alloys contain a lot less Zn. and there is not a set way of using the terms bronze or brass
Alloy Specifications Data Page
 

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Yes, it was the go to. but do you know what 85 triple 5 means? the last 5 means it contains on average 5% Zn.
I am well aware that 85-5-5-5 contains as much as 5% zinc. This alloy however is the most time tested and bullet-proof alloy that has been used for seacocks & thru-hull fittings. About 20 years ago Blake's (European brand) switched away from 85-5-5-5, what they built their reputation on, and went to DZR Brass. I have never once seen an older Blake's seacock dezinced nor have I seen a Spartan, Conbraco or 85-5-5-5 piece made by Groco dezinc. I have however seen newer Blake's and numerous "CR" DZR Brass seacocks dezinced and piles of standard yellow brass dezinced.

the newer DZR alloys contain a lot less Zn.
No they don't. The DZR alloys used by European boat builders contain a LOT more zinc than American seacocks do....

The alloy most used by European boat builders, when they don't use straight brass and unfortunately many do use a standard 60/40 brass, is called DZR brass. DZR Brass/CW602N is 62% Cu - 0.7% Sn, 35.2% Zn & 2%Pb. The alloy has .7% tin added to aid in dezincification resistance... Resistance being the key word.. 85-5-5-5 has 5% Zn and 5% Sn (tin is what really aids in corrosion resistance) and DZR Brass has 35.2% Zn and only .7% Sn........


The European ISO/RCD essentially allowed or created this move to DZR brass by specifying that a 5 year service life is suitable. DZR brass is less costly and easier to machine thus the European boat builders love it. If it makes it beyond year five that is all they care about and all it takes to build a boat to meet the ISO/RCD federal laws..

DZR Brass is not more corrosion resistant than 85-5-5-5 bronze, especially not out in the real world... The most proven track record I know of, for any alloy used for seacocks or thru-hulls, is 85-5-5-5 and this is why companies such as Spartan, Groco, Buck Algonquin and Apollo/Conbraco still use it to this day for seacock and thru-hull material. This is most likely because DZR brass would not pass / meet the UL/ABYC corrosion requirements...


and there is not a set way of using the terms bronze or brass
Alloy Specifications Data Page
85-5-5-5 has many names that get applied to it such as leaded gunmetal, ounce metal, bearing bronze, leaded red brass, tinned bronze etc. but there is no question about its durability in the marine environment. You could not pay me to install DZR on my own boat.

Sometimes we can learn from industry and large classification societies. A look at the shipping classification societies such as DNV (Det Norske Veritas) is but one source. The classification rules for big cargo ships says that a zinc content greater than 30% is not approved for seawater systems. Under DNV classification rules DZR brass "CR" marked seacock or valve or thru-hull/skin fitting would be disallowed but an 85-5-5-5 alloy would be fine.

Under ABS classification (American Bureau of Shipping) no alloy can contain any more than 15% zinc. DZR Brass fails this classification society too but 85-5-5-5 passes.

Under UL1121 any alloy containing more than 15% zinc must undergo an additional "10-Day Moist Ammonia-Air Stress Cracking Test". At the end of this test there; " shall show no evidence of cracking or delamination when examined using 25X magnification".. I've not known of any DZR product to pass UL 1121.

The problem, and where all this nonsense started, was the ISO/RCD:

"ISO/RCD:
Through-hull fittings for water shall be corrosion resistant, defined as material used for a fitting which, within a service time of five years, does not display any defect that will impair tightness, strength or function."


While DZR is certainly much better than standard yellow brass, what far too many European builders slap into boats, it is NOT 85-5-5-5 in terms of corrosion resistance..

Thanks but I will stick with a proven time tested alloy for my seacocks, and that would be 85-5-5-5....:wink
 

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I don't know the chem composition or maker of my thru hull or ball valves in some cases. Do I worry? What are the signs of impending failure? The ball valves are neither loose nor tight.

Should I consider replacing all or some of them in the Spring?
 

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I don't know the chem composition or maker of my thru hull or ball valves in some cases. Do I worry? What are the signs of impending failure? The ball valves are neither loose nor tight.

Should I consider replacing all or some of them in the Spring?
It should be embossed or etched into the body. Usually it is just part of the casting. If it says DZR then yes I would replace it. Keep in mind the parts are only supposed to have a service life of five years. So some will fail before that some after.

The EU standard has been a disaster, and it's a stupid way Tom save a trivial amount of money. But the series builders can shave a grand of the cost of a boat from the factory.
 

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WOW replace all the thru hulls and ball valves each 5 years? For real???? YIKES
 

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WOW replace all the thru hulls and ball valves each 5 years? For real???? YIKES
I'm not sure that is exactly what the certification standard means. While this seems to be a genuine quality problem, I believe the majority far outlive 5 years. I'm just not sure that majority is high enough. After the 5 years certification window, you become the test pilot.

I'm hoping to begin a swap out to Groco this spring. Don't think I stand a chance of getting to them all, but will start with those furthest beneath the waterline.
 

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Dirt Free
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I'm not sure that is exactly what the certification standard means. While this seems to be a genuine quality problem, I believe the majority far outlive 5 years. I'm just not sure that majority is high enough. After the 5 years certification window, you become the test pilot.

I'm hoping to begin a swap out to Groco this spring. Don't think I stand a chance of getting to them all, but will start with those furthest beneath the waterline.
In a perfect world they will not fail the day they pass the five year limit but a little galvanic or stray current action can make them fail very quickly (possibly weeks/hours respectively). Good quality bronze may take years or decades to be affected by the same current
 

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I'm not sure that is exactly what the certification standard means. While this seems to be a genuine quality problem, I believe the majority far outlive 5 years. I'm just not sure that majority is high enough. After the 5 years certification window, you become the test pilot.

I'm hoping to begin a swap out to Groco this spring. Don't think I stand a chance of getting to them all, but will start with those furthest beneath the waterline.
That'll be a big job Minne, some of the seacocks on the Beneteau built boats are tough to get to. I would bring rum and leave my sawza and sledge hammer at home. Good luck.
 
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