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Old 04-08-2016, 11:20 PM   #81
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CeeBee,

This is great information, thanks for sharing. If the problem persists you might look into one of these corrosion protection systems from ElectroGuard Corrosion and cathodic protection specialists for your boat, yacht or small ship. Prevent fresh water and salt water marine corrosion often referred to as marine electrolysis.
Thanks for passing on Aron!
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Old 04-08-2016, 11:28 PM   #82
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That is great news for you and many others. I hope he'll look objectively and also realize yours isn't an isolated issue. With all the positives of their boats and the way owners love them, it's a shame that they've let these issues remain a negative.
Hi BandB I am looking forward to the insights and input we can all get from the visit. Totally impressed with the responsiveness and interest from the manufacturer in partnering in looking for a solution. While making the investment flying someone across the country to really understand what's going on.
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Old 04-09-2016, 12:12 AM   #83
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Hi BandB I am looking forward to the insights and input we can all get from the visit. Totally impressed with the responsiveness and interest from the manufacturer in partnering in looking for a solution. While making the investment flying someone across the country to really understand what's going on.
It is an impressive move. It's what they should be doing, but many would not. There's an issue that you as a builder don't understand, go there.
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Old 04-09-2016, 12:29 AM   #84
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Anxious to learn the report.
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Old 04-09-2016, 06:12 AM   #85
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Originally Posted by aralston View Post
CeeBee,

This is great information, thanks for sharing. If the problem persists you might look into one of these corrosion protection systems from ElectroGuard Corrosion and cathodic protection specialists for your boat, yacht or small ship. Prevent fresh water and salt water marine corrosion often referred to as marine electrolysis.
You seem to have dropped the word "incorrectly" from your quote
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Old 04-09-2016, 06:58 AM   #86
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Update: As reported we thoroughly cleaned and treated the thru-hulls, inspected them at a haul out, tied them to a ground. Our suspicion was that Marina Del Rey was hotter. We were using 220v AC at the slip, that there was some stray currents at the marina etc, etc, etc. However, within 8 weeks of doing the repairs and back in our home port (pic attached) the same thing happened.

To Beneteau's credit, after I sent them pics on Tuesday, within an hour their Sr Service advisor from Annapolis called. We discussed the situation and he is arriving in the Bay Area to be on the boat this Monday to trouble shoot.

Please stand by.
CeeBee:
It's encouraging to hear Beneteau has been responsive.

I've been doggedly attempting to debunk the "hot marina" myth for years, and did so when this theory was first put forth. To some extent your experience bears out the fallacy of this myth, marinas aren't "hot", boats are. While AC shore power connections may facilitate galvanic corrosion, via the green safety ground, AC power, from a marina's mains or anywhere else, does not, with very rare exceptions and often where aluminum is concerned, cause stray current corrosion. Corrosion is virtually always a DC phenomenon, either via stray current, i.e. from a battery, or galvanic, from dissimilar metals.

While you issue may have been exacerbated by a malfunctioning or absent galvanic isolator, nearby vessels whose anodes are depleted, or a deteriorated bonding system, those are likely red herrings in this analysis, they do not represent the root of the problem.

Irrespective of the hot marina issue, in your initial post you noted/showed photos of the metal in these fittings, which had turned pink in locations. If so, this means it contains zinc, and that's almost certainly the cause of the problem.

Alloys that contain more than 15% zinc (this is brass by definition and even 15% is too much IMO) should not be used for underwater and raw water plumbing (such seacocks and fittings would not meet UL 1121, and thus lack ABYC H-27 compliance). Using it and relying on the vessel's bonding system to protect these metals from corrosion and dezincification is shear folly. Once the zinc anodes are depleted, the next least noble metal, the zinc-bearing plumbing fittings, will begin to corrode. That "formula" is typical of all bonding system arrangements, however, through hull fittings and seacocks known to contain this level of zinc are far more susceptible to corrosion than those that contain little or no zinc; they should, therefore, not be used.

From an article on the subject...

"ANSI/UL 1121.8.1 The components of a through-hull fitting or sea valve shall be formed of galvanically compatible materials having the strength and resistance to corrosion necessary to withstand intended and abnormal use to which they are likely to be subjected.

ANSI/UL 1121.8.3 A part made of drawn brass or machined from brass rod containing more than 15 percent zinc shall be subjected to the 10-Day Moist Ammonia-Air Stress Cracking Test."
What's Below Your Waterline? - Seaworthy Magazine - BoatUS

The only exception to the zinc-bearing alloy rule is fittings that are embossed DZR, which stands for dezincification resistant. From the same article...

"Unfortunately, a huge range of alloys lies between true bronze with very little or no zinc and true brass which contains a high percentage of zinc. Two common alloys often used in marine applications are 85-5-5-5 and DZR. 85-5-5-5 contains 85 percent copper, 5 percent zinc, 5 percent lead and 5 percent silicon and can be used below the waterline. Some European manufacturers use something called DZR brass, a dezincification-resistant brass alloy. This alloy has a higher zinc composition than many other copper alloys (30 percent or more), but it also includes trace amounts of other metals meant to retard zinc corrosion or leaching. The more zinc an alloy contains, the more prone it is to dezincification, therefore, alloys with little or no zinc content are more desirable, and typically more costly. Accordingly they can be an attractive, though inferior, alternative for cost-conscious builders or do-it-yourselfers."

The fittings used in your seacock installation do not appear to be of the DZR variety, and even if they were they are clearly not working as they are dezincifying.

The only lasting solution, IMO, is to replace them with seacocks, metallic or non-metallic, that meet ABYC H-27/UL 1121 (both the hardware and the installation). Such compliant seacocks are clearly labeled by their manufacturers.
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Old 04-09-2016, 08:00 AM   #87
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I've been doggedly attempting to debunk the "hot marina" myth for years, and did so when this theory was first put forth. To some extent your experience bears out the fallacy of this myth, marinas aren't "hot", boats are. While AC shore power connections may facilitate galvanic corrosion, via the green safety ground, AC power, from a marina's mains or anywhere else, does not, with very rare exceptions and often where aluminum is concerned, cause stray current corrosion.
NACE and a large number of other respected authorities have produced studies, papers, report etc. showing AC current can cause corrosion of metals. A Google search will bring them up.
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Old 04-09-2016, 08:44 AM   #88
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Bonding wires connecting your high %zinc brass pseudo bronze fittings makes them act like zincs, so yeah they corrode and corrode greater due to the attached bonding wires on them.
Say you coated-sealed the outside of these things. Then they would look good on the outside, but the inside would still corrode. Although less corrosion may be occurring on the inside due to less exposure to free air oxygen.

I have a wood hull. When I got the boat, all the OEM bronze fittings I removed examined reinstalled them back as not a thing was wrong, them being in good condition and the boat was built in 1970. I had two areas where the wood delignified around the base, not bad for 45 years of constant salt water use.

I disconnected the wires to all thru hulls, but left bonding wires to everything else. The delignification is due to acid attack on wood in contact with metals long term takes decades I think to destroy wood. . I simply wire brushed the wood, and sealed with epoxy and polyurethanes. In effect the sealed wood is no longer in contact with the metals. The metals touch plastics no longer the wood.
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Old 04-09-2016, 09:10 AM   #89
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NACE and a large number of other respected authorities have produced studies, papers, report etc. showing AC current can cause corrosion of metals. A Google search will bring them up.
Proof of AC too high a saturation level in some marinas' waters: Causes can be poor on-dock electrical outlet maintenances, bad grounds, lines' under dock drooping onto water with cracked insulation, or boat extension line droops into water with somehow permeable insulation wrapping. Seems to me that in addition to possibly stray DC current aboard a boat; this stray AC current in water must have negative effects on diodes if anodes are not correctly placed/kept-up-with.

Boat Talk: How faulty wiring at marinas can be silent, swift killer | MLive.com

Back in the day (mid 1960's) - South shore LI, NY waters: For nearly a year we had a 37' wood-boat, raised deck sport fisher with cleaned-out bilge and no batts aboard; swapping Nordberg Knight gas for Perkins diesel. Zinc seemed to deteriorate same rate as with batts aboard.
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Old 04-09-2016, 09:43 AM   #90
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I often wonder: With high tech capabilities for plastic material compositions and plastic part manufacturing why many boat through hull apparatus' have not been made of super-duper plastic? That would virtually eliminate diode corrosion in those cases - Correct???

Are the reasons:

Tests prove out metals are stronger, more resilient? Manufacturers try not to get into new tooling costs? Soooo many already manufactured through hull parts providing inertia as well as continued same-ol / same-ol manufacturing process momentum? Too costly for the best plastic materials to be used, in comparison to corrosion-prone metal alloys??

Seems there must be a reason! Anybody???
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Old 04-09-2016, 10:17 AM   #91
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Plastic is weaker than metal.
Good bronze parts last a very very long time.
Maybe the incentive is too use inferior metal parts to guarantee replacement, a planned outcome to keep sales going?

If thru-hulls were made of titanium, no one would ever need another one in a thousand lifetimes.
I would also say if thru-hulls were all made of good bronzes designed for durability in ocean water, no one will ever need another one in their lifetime, maybe even to their grandchildren's generation of ownership.
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Old 04-09-2016, 03:06 PM   #92
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Bonding wires connecting your high %zinc brass pseudo bronze fittings makes them act like zincs, so yeah they corrode and corrode greater due to the attached bonding wires on them.
Lots of great feedback and points of view from everyone.

Yep disconnecting the bonding wires we installed was part of the initial conversation with Beneteau, however, that was done post the first incident. After I sent him pics of the before and after (prior bonding) and the connections for the raw water feed to the stuffing box. He simply said "I need to come see this in person, I'll be there next week".

We also had a diver in the water yesterday who has been checking the zinc burn every couple of weeks since the haul out. Basically over a 3 week period from 90% to 75%.

I'm not sure if there is a lone culprit or a series of issues creating a domino effect. Which is why I'm looking forward to the "on-site" visit and learnings that may come from it.
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Old 04-10-2016, 06:23 AM   #93
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NACE and a large number of other respected authorities have produced studies, papers, report etc. showing AC current can cause corrosion of metals. A Google search will bring them up.
I've read those papers. I didn't say it was impossible, just very rare, it requires very high current density and it typically is an issue with aluminum. In my entire corrosion analysis career (I too have an ABYC Corrosion Cert). I've seen it just twice, both times it affected aluminum out-drives. It's an interesting subject for a debate, however, in this case the pink metal is a clear indication of dezincification.
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Old 04-10-2016, 07:08 AM   #94
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Forespar Marelon fittings are composite.....and seem very durable...probably more so than if your bronze is attacked or wearing away from flow.


What Marelon Is
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Old 04-10-2016, 07:50 AM   #95
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Download to a pdf where a 8lb sledge was hitting various parts and how they broke.
http://www.cruisersforum.com/forums/...7&d=1369938639

Post #34 worth looking at.
Marelon Seacock Replacement - Page 3 - Cruisers & Sailing Forums

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Quote:
Schedule 80 PVC lasted 1 hit. The Marelon fittings lasted two hits. Picture 1 is a Marelon fitting; notice how cleanly it sheared. As a comparison, bronze is good for 6-8 hits.

Picture 3 shows a Turncouple barbed fitting after 18 hits. The Turncouple is molded using a 20% long glass filled Thermopolyurethane (TPU). This Turncouple was molded with 20% long glass fiber and exceeded the H-27 Tensile Strength and Flexural Modulus requirements.

Several non-glass loaded Turncouple taiIpieces were tested sustaining 13 hits before cracking. This material does not meet the ABYC material standard, but had over six times the impact strength as Marelon.

The Picture 4 shows a full Turncouple assembly after 50 hits. It has no cracks, especially where the nipple threads screwed into the cast iron flange. It was still functional. The highest impact value I was able to get testing any other material was 3 hits using a 33% glass loaded Dupont nylon of our own manufacture.
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Old 04-10-2016, 08:57 AM   #96
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Download to a pdf where a 8lb sledge was hitting various parts and how they broke.
http://www.cruisersforum.com/forums/...7&d=1369938639

Post #34 worth looking at.
Marelon Seacock Replacement - Page 3 - Cruisers & Sailing Forums

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Am I to understand that "Turncouple" is superior material for through hull fittings? When I try to locate more net info it seems all Turncouple sites are closed. e.g. www.turncouple.com ???
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Old 04-10-2016, 09:06 AM   #97
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Bonding wires connecting your high %zinc brass pseudo bronze fittings makes them act like zincs, so yeah they corrode and corrode greater due to the attached bonding wires on them.
Say you coated-sealed the outside of these things. Then they would look good on the outside, but the inside would still corrode. Although less corrosion may be occurring on the inside due to less exposure to free air oxygen.

I have a wood hull. When I got the boat, all the OEM bronze fittings I removed examined reinstalled them back as not a thing was wrong, them being in good condition and the boat was built in 1970. I had two areas where the wood delignified around the base, not bad for 45 years of constant salt water use.

I disconnected the wires to all thru hulls, but left bonding wires to everything else. The delignification is due to acid attack on wood in contact with metals long term takes decades I think to destroy wood. . I simply wire brushed the wood, and sealed with epoxy and polyurethanes. In effect the sealed wood is no longer in contact with the metals. The metals touch plastics no longer the wood.
You did the right thing by disabling the bonding system in this case, wooden boats are an exception. This is a subject that's not understood well enough by many wooden boat owners, I've carried out repairs on many delignified hulls that could have been avoided with this approach.

Traditionally wooden boats are not bonded for just this reason, delignification. The delignification by the way is caused by the creation of an alkaline solution (a natural occurrence at cathodes, i.e. anodically protected underwater metals, it has nothing to do with the wood per se) which is a base rather than an acid, around bonded through hulls and underwater hardware, which does damage the timber. This phenomenon occurs on FRP vessels as well, it's just not an issue because FRP is immune to alkaline attack ("over-protection" can be an issue on aluminum vessels and drives). In extreme cases on FRP it can cause anti-fouling paint failure around bonded underwater hardware.
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Old 04-10-2016, 09:29 AM   #98
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Am I to understand that "Turncouple" is superior material for through hull fittings? When I try to locate more net info it seems all Turncouple sites are closed. e.g. www.turncouple.com ???
Yeah dont know what is turncouple, I was wondering if it is a style name of pipe type, not a maker of pipe. Maybe he is talking of a 'union' or a 'close' pipe nipple. A turncouple might also be a type of pipe union, a nut screws tight to a base and both ends female threaded

Polyethylene plastics are nearly indestructible if whacked since they flex and rebound, have strong threads, don't corrode. Fire would ruin them. So why not use that?
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Old 04-10-2016, 09:34 AM   #99
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You did the right thing by disabling the bonding system in this case, wooden boats are an exception. This is a subject that's not understood well enough by many wooden boat owners, I've carried out repairs on many delignified hulls that could have been avoided with this approach.

Traditionally wooden boats are not bonded for just this reason, delignification. The delignification by the way is caused by the creation of an alkaline solution (a natural occurrence at cathodes, i.e. anodically protected underwater metals, it has nothing to do with the wood per se) which is a base rather than an acid, around bonded through hulls and underwater hardware, which does damage the timber. This phenomenon occurs on FRP vessels as well, it's just not an issue because FRP is immune to alkaline attack ("over-protection" can be an issue on aluminum vessels and drives). In extreme cases on FRP it can cause anti-fouling paint failure around bonded underwater hardware.
Hi, thanks, yes, it is a base not an acid.
I have a 2014 album here with some repairs on the hull. Prior to this I did an extensive repair in 2006 with all the bottom planks removed, new frames and bronze screws and also coated the wood with Sani Tred Permaflex inside and outside. My hull goes in and never has to take up water to seal. All the underwater seams were sealed with PL premium poly construction adhesive mixed 50-50 with sawdust.

In 2014 I experimented with Loctite's Black PL polyurethane roof and flashing mixed with 1/32 milled glass fibers about 70% to 30% fibers on the bow going back 10 feet. I liked it a lot, made a very tough rubber coating. I also coated the entire keel in Black PL without the fibers.

Hull is dry and been fine, no peeling, no cracking, no splitting, no rotting.

https://photos.google.com/share/AF1Q...gtRUNHTXp5d09n
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Old 04-10-2016, 09:42 AM   #100
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Yeah dont know what is turncouple, I was wondering if it is a style name of pipe type, not a maker of pipe. Maybe he is talking of a 'union' or a 'close' pipe nipple.

Polyethylene plastics are nearly indestructible if whacked since they flex and rebound, have strong threads, don't corrode. Fire would ruin them.
I'm on strong search to locate absolute best strongest,longest lasting material for through hull fittings. I feel it is surely possible with high tech material advancements that there could be something better than what has been age old choices... but, maybe not??!!

Although I had planned to haul and do boat bottom this just passed winter, life circumstances threw my-time for that plan "overboard" - LOL

Now planning to enjoy as many times as possible this season and haul next winter. Gives me even more time for research. One thing is for sure. When she's out of water... taint going back in... till I am confident all her bottom needs have been correctly addressed.
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