Flanged seacocks installation with Beneteau grid liner?

[dLj]

I'm really confused why you keep coming at me, since I haven't been trying to argue with you at all. You asked what the thruhulls were made of and I told you Beneteau said they were duplex brass, of which DZR is one type, but that Beneteau (to my knowledge) hasn't specifically said that. That is all. I thought it was a helpful comment.

Yes, I said DZR brass, because that is what Yachting Monthly called it, and is what many of the owners have called it. It has been described as such in the forums where the problem has been discussed. It may not be DZR, and I admit that, particularly after seeing that Beneteau just called it "duplex brass".

As for people with the problem gathering together and hiring a professional, these things happen in isolation over time. It's not like everyone has their boat pulled out together and finding the same issues with them and deciding to take collective action. Particularly since they have no legal recourse if the thruhull is 5yrs or older. If it was me with a failed 6yr old thruhull and no legal recourse, I'd just replace with a better one and go sailing. But sure, it'd be a good thing to do.

This whole thing started with the OP asking about his thruhulls and wanting to replace them because they were brass. When everyone refused to believe that, I posted that they were brass, and this has been a contentious issue with Beneteau, Jeaneau, Hanse, and several other manufacturers. That is when certain people here started taking the piss out of me. Then other owners of Beneteaus posted they are brass and that they found some issues with theirs.

So let's agree that there have been an unusual amount of failures of these thruhulls in these boats compared to other boat manufacturers not using them, and that we don't know the exact composition other than "duplex brass". After that, we are all free to speculate on what type of brass, whether it is normal for a thuhull to only last 5yrs, and whether these failures are to be blamed on the boat and not the material.

Mark

@colemj Take a deep breath guy - I'm not coming at you. Not in the least. I've supported your statements where I could. I've thanked you for bringing this up. I haven't been aware of this problem and I'm glad you brought it up.

I'm not "everyone" that refused to believe the original thruhulls were brass. You may want to go back and review earlier posts.

Frankly, I'm really interested in this topic. I happen to be pretty knowledgeable in the subject of figuring out these kinds of problems. My first post was more trying to suggest the OP might not need to go through all the work to put in flanged seacocks. That's really up to the OP.

If you can hang in there, I'd like to ask some more questions as you seem to know a lot more about this than I do. You state above "this has been a contentious issue with Beneteau, Jeaneau, Hanse, and several other manufacturers". Do you know what other manufacturers? Can you provide links or references to this even if it's possibly just one or two of these manufacturers?

You also state:

"So let's agree that there have been an unusual amount of failures of these thruhulls in these boats compared to other boat manufacturers not using them, and that we don't know the exact composition other than "duplex brass". After that, we are all free to speculate on what type of brass, whether it is normal for a thuhull to only last 5yrs, and whether these failures are to be blamed on the boat and not the material."

Now there are a couple things in that paragraph that are difficult - for me the biggest one is "free to speculate".... It is indeed one of the biggest problems that the internet and the marine environment seem to have in common - far too many folk "speculating"....

I much prefer to work with data only.

dj

p.s. Just a FYI - Yacht World is not what I would consider a "reliable" source... hahahahaha

 

[dLj]

Nobody with these boats having failed thruhulls care if it is DZR or not. They are only concerned that their thruhulls are failing after an unexpectedly short time,. and in ways that were not readily apparent from normal sight and use.

Mark

They may not care, but if in fact it's a fundamental material problem - we should all care. And it should be brought up to the organizations that state this is an appropriate alloy to use. Now, you may not know how to do that, but I do....

dj

 

[Ralph Johnstone]

That is when certain people here started taking the piss out of me.

Yes, you're right. And the reason some of us do is that you open your mouth and out comes a selection of some pretty far fetched ideas without a trace of authentification to back them up.

We all have opinions, great. I said "Extremely unlikely" to @kodiak when he said the thru-hulls were brass. That's my opinion. So sue me. It's just my opinion.

It's when you try to pass off your opinions as fact without any authentic backup that some of us get riled. Many of us here have been ruled by the need for authentification of statements throughout the length of our careers. I don't believe this has been your background. But don't get me wrong, it doesn't matter. Nobody cares. We all have somewhat different backgrounds and this need for proof does not appear in everyone's career.

As far as tesing of DZR, Yup, I only stated one of the ISO standards which the sample must pass, ISO 6957:1958 which tests for stress corrosion using NH3 gas and 6509-1:2014 which uses copper chloride as its test medium. A stress corrosion test is mandantory for two reasons : brass is more sensitive to stress corrosion than most metals and most brass winds up in a stressed condition. Think anything with threads.

One of the reasons I ask for authentification is to determine whether you've correctly interpreted the information you are using as a backup. Unfortunately, you've made an error in the interpretation of ISO 9093-1:1994 . If you had included a few more lines of text, you would have seen what section 3 in this standard is all about :

The purpose of section 3 is to define a number of possibly obscure words and when you look at 3.3 corrosion-resistant, what it says in simple terms is the following :

The word, corrosion resistant, is defined by this document, ISO 9093-1:1994 as a material which can be exposed to a corrosive service time of five years and not show any corrosion which will affect its tightness, strength, or function. Or in other words, after five years of service time the sample still looks like new.

On the other hand, if the material does show corrosion within five years under the same conditions, and that corrosion will affect its tightness, strength, or function, then ISO 9093-1:1994 does not define it as being a corrosion resistant material. Or in other words, it looks like crap before the end of five years.

However, as you said, ISO 9093-1:1994 has been replaced by ISO 9093:2021 and mention of corrosion is no longer present. The above refers to 1994 to the next update of the ISO standard.

May I suggest this is the source of all of the bull- regarding changing the Beneteau DZR brass thru-hulls at five years to something better.

As far as AZR brass goes, if it can conform to to the required ISO standards, it is deemed a corrosion resistant material and your opinion isn't worth the powder to blow it to hell. Another DZR sample may not conform to the standards so it is not listed as corrosion resistant.

I think (hope) @dLj may agree with me here in that DZR brass may fall into a category which is just a little too suseptible to dropping into the corrosion suseptible category with very small changes in its metallurgy. A snap phase change which knocks out the DZR ? Maybe 10% of the thru-hulls supplied to Beneteau were not corrosion resistant while the other 90% were not suseptible to a loss of zinc. Who knows? Stranger things have happened.

 

[dLj]

@Ralph Johnstone - You really could be gentler in expressing your opinions. We are - at least I am - trying to make this forum a friendly place and for folks to learn and feel welcome. Everyone comes with a different background and a different knowledge base. I come here to learn. I also like to think I add knowledge in some areas where I feel I can add to the conversation.

I recall a number of years ago, there was a guy that bought a brand new vehicle - first year it was produced. Shortly after buying, it began doing some really strange things and from the guys description, you would have thought someone was practicing voodoo on his vehicle. He brought it into the dealership where he bought it and as they couldn't reproduce the problem, they ended up mostly dismissing him. Through frustration, he brought it into other dealerships. He finally brought it into one dealership where the owner actually knew one of the design engineers at corporate headquarters. He called the guy up and explained everything this guy was going through. The engineer listened and said he'd look into it. Turns out it was a weird vapor lock condition that would appear and disappear due to a simple geometry (IIRC) within the fuel feed of the fuel injection system. So they figured out why it was happening and redesigned the fuel injection system for subsequent vehicles. Problem fixed. But it required listening to some highly non-technical explanations of vehicle behavior.

I think (hope) @dLj may agree with me here in that DZR brass may fall into a category which is just a little too suseptible to dropping into the corrosion suseptible category with very small changes in its metallurgy. A snap phase change which knocks out the DZR ? Maybe 10% of the thru-hulls supplied to Beneteau were not corrosion resistant while the other 90% were not suseptible to a loss of zinc. Who knows? Stranger things have happened.

While the above may be possible, it would in itself then earmark this alloy as inappropriate. You can't have an alloy that sits on a "knife edge" of composition and be listed as a corrosion resistant alloy.

Think about 304 and 316 austenitic stainless steels. Those were the original two alloys. But then it was discovered that welding these alloys could create what's called sensitization, and they could become susceptible to corrosion in the HAZ (heat affected zone) of the weld. Both of these alloys allowed the carbon content to be 0.08%. It was discovered that keeping the carbon content below 0.03% this problem went away. Hence 304L and 316L - the L standing for low carbon content - were created and the sensitization problem went away.

dj

 

[colemj]

Many of us here have been ruled by the need for authentification of statements throughout the length of our careers. I don't believe this has been your background.

You don't know anything about me, but I'd wager a donut my background training has been more rigorous than yours in this area. You really don't want a pissing match there.

Unfortunately, you've made an error in the interpretation of ISO 9093-1:1994 .

I didn't make an error. The CE requirements were for a service life of 5yrs. Yes, that is a minimum, but any fitting lasting 5yrs and 1 day is considered past this time. According to owners reporting in forums, Beneteau has refused warranty claims for failures just over 5yrs, and has put fairly onerous inspection requirements to deny claims less than 5yrs. It is pretty telling that this CE requirement changed and Beneteau no longer uses those fittings.

You simply choose to twist your reading and understanding to avoid these facts.

Mark

 

[dlochner]

You engineers can be a tough group. For the mere mortals who might still be following this thread, could someone summarize this discussion in plain language and identify areas of agreement and disagreement. And then maybe agree to disagree.

 

[colemj]

If you can hang in there, I'd like to ask some more questions as you seem to know a lot more about this than I do. You state above "this has been a contentious issue with Beneteau, Jeaneau, Hanse, and several other manufacturers". Do you know what other manufacturers? Can you provide links or references to this even if it's possibly just one or two of these manufacturers?

Group Beneteau covers several brands, and is the largest manufacturer, so most of the issues are with their brands. Hanse is another that has had owners complaining for the same reason. Essentially, any boat built under CE regulations that are building to a price point are likely to have this issue, although the lower counts of smaller brands may not rise to the top as anything more than a one-off example.

I could provide links to the owner's groups, forums where this has been discussed, etc, but this issue played out in many places a while ago, and it is very easy to find for oneself. I'm surprised this is something new to people, and frankly, I'm just not going to expose myself to any more abuse from people who refuse to do any legwork themselves (not you).

This entire kerfluffle here is completely analogous to another Group Beneteau issue, where at least one model of their catamarans had undersized and poorly engineered main bulkheads that were connected solely by an adhesive. Causing structural failures of the boat itself. Like with the thruhulls, Beneteau refused to acknowledge anything wrong because they built them to minimum CE standards, they said the problem was very isolated to 1-2 boats, they blamed the owners for sailing them in conditions outside the design (which was CE Cat A), or that the owners did not follow Beneteau's reefing instructions, and they stated that these bulkheads should be inspected by a professional annually (which requires some destructive disassembling of parts of the boat).

Now, if this was the topic here, I'd be pilloried for saying the bulkheads were improperly designed as 4 independent sheets of unglassed 12mm plywood that were only connected to the boat with a bead of Plexus.

You would likely be banging me for saying it was Plexus, when Beneteau only claims it was a methacrylate adhesive. The other guy would be banging on me to prove with finite analysis that 12mm isolated plywood panels were not appropriate for this use, while bringing up unrelated and non-applicable random stuff he dug up to prove otherwise. Both of you would be asking for links to the problem, when it has been a widespread very public one with many examples to find, and not just a single example of "gotcha" buried somewhere deep in the internet.

Lost in chasing these exact details would be the fact that it happened. In this case, owners did band together and threatened a lawsuit, along with very publicly describing the issue and Beneteau's responses, and Beneteau provided a fix to those who came forward without admitting there was actually a problem. The fix was a bracket bandaid that is never going to hold up, but in some of the more extreme cases, they did pay for professional to reinforce and glass up the bulkhead.

And in a similar vein, when that model was superseded with a new very similar model, the bulkhead design and installation was completely changed.

Mark

 

[colemj]

You engineers can be a tough group. For the mere mortals who might still be following this thread, could someone summarize this discussion in plain language and identify areas of agreement and disagreement. And then maybe agree to disagree.

Sure, it is pretty simple as an overview.
- The OP wants to change his thruhulls because he understands others have had issues with the same ones he has.
- The discussion turned to whether they were brass or bronze (they are brass, as I think all can agree now)
- The discussion then got caught on semantics of which type of brass. Beneteau states "duplex brass"
- I said DZR brass, which is a type of duplex brass, but that became contentious. The debate now is whether it is DZR or some other type of duplex brass
- Then the debate was whether the issue exists at all, and demands for proof that anyone has the problem. Even though others in the thread with these boats stated they did.
- One guy here is just lobbing ad hominem attacks and posting unrelated or tangential stuff.
- Another guy is reasonable and wants to understand the root problem, but seems to be holding me personally to account for this.
- None of this is helping the OP decide whether he can enlarge his liner cutout to install a larger seacock.

Mark

 

[colemj]

Currently there are wooden backing plates in that area... Not original OEM, so not sure what was there before... Haven't seen hull thickness there yet... Figured I'd just replicate what's there now, but with the G10 improvement. G10, in the quantity I need, is not a lot of money and I have a drill press, a few cheapy diamond hole saws from Amazon, some water and bob's your uncle.. Not hard, so figured I just go all in where I can.

I understand. The wood backing plate was likely because the thruhull didn't have a flange and it was used for better load spread. It is unlikely that a monohull hull would be thinner than the minimum thickness for TruDesign thruhulls. I did have one or two places on our boat where I did need to build up thickness to meet the minimum, but we are a keel-less catamaran constructed from vinylester and directional s-glass.

Even if you don't need the backing plate, it is good to glue it on because you are assured a completely flat mounting surface. Hulls insides can have a lot of small bumps and ridges even though they look flat.

I've got to try the water trick. Don't know why that never occurred to me. I've got expensive carbide hole saws made for cutting cast iron and 1" metal plate, which go through fiberglass great, but get red-hot and can grab hard. Plus water solves the dust problem.

Mark

 

[jbmia]

Sure, it is pretty simple as an overview.
- The OP wants to change his thruhulls because he understands others have had issues with the same ones he has.
...

This looks like a good summary to me, but the OP's question was actually a different one.

Production boats like Beneteau use a hull matrix/liner that restricts access to the underlying hull. As a result, some OEM thru-hull and valve installations do not allow for the installation of a backing plate and seacock without cutting back the liner.

The decision typically comes down to:

1. Replacing existing fittings using an approach similar to the OEM install.
2. Cutting back the liner to create space for a backing plate and seacock or adapter.

The OP specifically asked about experiences with cutting back the liner, apparently seeking advice on feasibility and approach.

Despite three pages of forum discussion, no one has directly answered the OP's question so far.

I've been searching for detailed documentation on this topic myself and have yet to find a clear, step-by-step example—only scattered comments. If someone were to thoroughly document a thru-hull replacement, including their approach to modifying the liner, with before-and-after photos, it would be an invaluable resource for the thousands of owners with this OEM configuration looking to upgrade to a more robust installation. I'll definitely document the process if I end up taking the plunge.

 

[colemj]

This looks like a good summary to me, but the OP's question was actually a different one.

Production boats like Beneteau use a hull matrix/liner that restricts access to the underlying hull. As a result, some OEM thru-hull and valve installations do not allow for the installation of a backing plate and seacock without cutting back the liner.

The decision typically comes down to:

1. Replacing existing fittings using an approach similar to the OEM install.
2. Cutting back the liner to create space for a backing plate and seacock or adapter.

The OP specifically asked about experiences with cutting back the liner, apparently seeking advice on feasibility and approach.

Despite three pages of forum discussion, no one has directly answered the OP's question so far.

I've been searching for detailed documentation on this topic myself and have yet to find a clear, step-by-step example—only scattered comments. If someone were to thoroughly document a thru-hull replacement, including their approach to modifying the liner, with before-and-after photos, it would be an invaluable resource for the thousands of owners with this OEM configuration looking to upgrade to a more robust installation. I'll definitely document the process if I end up taking the plunge.

Hmmm. My last bullet point was this: "- None of this is helping the OP decide whether he can enlarge his liner cutout to install a larger seacock."

And my first response to him was this: "The OP should cut the liner back as far as needed to install a new seacock. There is nothing structural to worry about, as these are not installed on stringers - just the connecting liner. It looks like the fill around it is just caulking, and is only there to prevent things from finding their way into the liner irretrievably."

While the liner may provide a small amount of web support to the grid beams, it can be cut into without too much worry, like the manufacturer did. Enlarging the existing cutout a minor amount won't affect anything. The grid beams themselves should not be cut into.

Mark

 

[dLj]

- Another guy is reasonable and wants to understand the root problem, but seems to be holding me personally to account for this.

Mark

That part of your response would be directed towards me. I apologize if that's how I came off.

I am not holding you personally responsible.

I had hoped I'd written responses that made that clear but I will go back and review how I wrote things and make adjustments in the future.

dj

 

[jbmia]

Hmmm. My last bullet point was this: "- None of this is helping the OP decide whether he can enlarge his liner cutout to install a larger seacock."

And my first response to him was this: "The OP should cut the liner back as far as needed to install a new seacock. There is nothing structural to worry about, as these are not installed on stringers - just the connecting liner. It looks like the fill around it is just caulking, and is only there to prevent things from finding their way into the liner irretrievably."

While the liner may provide a small amount of web support to the grid beams, it can be cut into without too much worry, like the manufacturer did. Enlarging the existing cutout a minor amount won't affect anything. The grid beams themselves should not be cut into.

Mark

Fair point. And good suggestions. Looks like I missed those amidst everything else. My apologies.

To expand a bit, I think my approach to expanding the hole would be to:

• Remove the thru hull first and examine the area closely to see if there's any glue or sealant under the liner surrounding the existing hole... and if so perhaps digging around a bit to see if it's easily removable.
• If no sealant, etc or it looks like it's removable, I'd likely tap in a bung with a flat surface which is fairly close to level with the surrounding liner, where the center of the bung is precisely marked.
• I'd then use a carbide or diamond coated hole saw to drill out the liner where the arbor bit is drilled into the center of the bung.
• In my case, I'd likely go with a 4 1/2" backing plate since and there's not really a lot of space between the grid beams, at least in my boat. Larger backing plate would be better if more space is available.
• I'd probably take the time flush the area between the hull and liner at that time as well since that's an issue with these boats, especially in the areas between the galley and companion way.
• From there I'd glass in the backing plate with thickened epoxy and proceed with the rest of recommended install processes outlined in marinehowto.com

Would definitely appreciate any constructive feedback, suggestions.

 

[Ralph Johnstone]

I could provide links to the owner's groups, forums where this has been discussed, etc, but this issue played out in many places a while ago, and it is very easy to find for oneself. I'm surprised this is something new to people, and frankly, I'm just not going to expose myself to any more abuse from people who refuse to do any legwork themselves (not you).

Same old, same old, same old. I (referring to yourself) quote my opinions as fact and tell you to do the legwork and confirm them. No CE copy re thru-hull failure, no examples of thru-hull failures, no warranty from Beneteau advising the purchaser to beware of thru-hull failure, nothing. Very slick indeed.

You don't know anything about me, but I'd wager a donut my background training has been more rigorous than yours in this area.

Oh, you're a pro alright and it's not related to anything technical.

I have no further comments on this posting and leave all further back and forth to @dLj as his motives are far more noble than mine. Just remember that the lack of any factual evidence is becoming very conspicuous.

 

[Tally Ho]

I replaced a bunch of thruhulls on my O’Day 322 that also uses a pan liner. In areas where the new thruhull nut was too large, I had to cut the liner back to get clearance. I used a hole saw of the correct diameter, but without the pilot bit. It was hard to get the hole saw started (wants to walk all over the place without the pilot bit), but starting out slowly and getting a groove started before cutting faster was the trick. And obviously, you need to be very careful about going into the hull. I had some space between the liner and the hull, so I was able to tell when I punched through the liner.

You could also try an oscillating tool, with an appropriate blade to cut the opening bigger (if you have room).

Greg

 

[dlochner]

I used a hole saw of the correct diameter, but without the pilot bit. It was hard to get the hole saw started (wants to walk all over the place without the pilot bit),

Hot glue a piece of scrap wood in the hole for the centering bit. Once the hole saw starts cutting it doesn't matter if the block starts to spin.