The cult of the Proper Flanged Thru-hull

[Dockhead]

Originally Posted by Dockhead

You don't cut them -- you order them in the right length to begin with.

I have written, however, to Maestrini to ask them to confirm how they are threaded, and I will post their answer. The Maestrini technical materials state that with some exceptions all of their products have taper external threads and parallel internal threads to make a UNI EN 10226-1 standard joint.

However, I note that Groco BSP fittings are parallel for both through hull fitting (https://www.groco.net/products/fitti...th-series-bspp) and ball valve (https://www.groco.net/products/valve...es-bspp-thread), which is also a compatible combination. Also, they sell "combination thread" ball valves in NPT which is compatible with NPS through hulls.

So, your idea that all these flangeless assemblies have dangerous and incompatible threads is simply wrong, as we've been telling you. One way or another, I guarantee that the Maestrini assemblies used on all high end European boats have compatible threads. I'm still baffled that you could think that the entire European boat industry could be making boats which all fail the very stringent and detailed ISO 9093:2020 standard which is a legal requirement. Just imagine the lawsuits. This is, of course, nonsense.

Here is what Maestrini answered:

"Good morning [Dockhead],

"many thanks for your interest in our accessories.
Here attached I'm sending you data sheets of both items 2051 (bronze thru-hull) and 28910 (bronze ball valve).

"Both accessories have ISO 228-G thread = PARALLEL (BSPP).

"It's true that in our catalogue we mention 'products are mostly taper thread for external threads'. 'Mostly'. But a few of them, such as hose connectors, thru-hulls, extensions... have parallel threads.

"We confirm that the valve can be screwed directly onto the thru-hull.
The Vittoria valves are approved by RINA, as per attached certificate.
The bronze thru-hulls conform to the provisions of the ISO 9093:1 standard = hull thickness as shown in our attached catalogue page.
I'm sending you also a table with specific data concerning item 2051 (i.e. maximum allowable hull thickness if you want to use item 2051).

"I hope the above information and the attachments are exhaustive and answer your questions. If anything else is needed, do not hesitate to get in touch."





They sent a bunch of other documents, including RINA certifications.

I was mistaken about the threading of the mushroom fittings, but this is not relevant -- the threads are compatible. With regard to everything else -- I rest my case.

[Pete7]

Originally Posted by s/v Jedi

I still think valves in the EU have a tapered thread but of course a manufacturer can create special valves for these applications. I also still think that the EU skin fittings are parallel/straight thread and not tapered, but we’ll find out I guess.

Nick, don't think I have ever seen a tapered valve or through hull. ASAP are one of the major suppliers on line in the UK.

https://www.asap-supplies.com/produc...mm-long-403105


https://www.asap-supplies.com/produc...e-ports-405705

[boatpoker]

Originally Posted by Dockhead

Here is what Maestrini answered:

"Good morning [Dockhead],

"many thanks for your interest in our accessories.
Here attached I'm sending you data sheets of both items 2051 (bronze thru-hull) and 28910 (bronze ball valve).

"Both accessories have ISO 228-G thread = PARALLEL (BSPP).

"It's true that in our catalogue we mention 'products are mostly taper thread for external threads'. 'Mostly'. But a few of them, such as hose connectors, thru-hulls, extensions... have parallel threads.

"We confirm that the valve can be screwed directly onto the thru-hull.
The Vittoria valves are approved by RINA, as per attached certificate.
The bronze thru-hulls conform to the provisions of the ISO 9093:1 standard = hull thickness as shown in our attached catalogue page.
I'm sending you also a table with specific data concerning item 2051 (i.e. maximum allowable hull thickness if you want to use item 2051).

"I hope the above information and the attachments are exhaustive and answer your questions. If anything else is needed, do not hesitate to get in touch."

Attachment 264398

Attachment 264399

They sent a bunch of other documents, including RINA certifications.

I was mistaken about the threading of the mushroom fittings, but this is not relevant -- the threads are compatible. With regard to everything else -- I rest my case.

Am I reading this correctly ? Their ball valves a nd throughulls are both parallel threads and they use bronze not brass ?
Has not that been ABYC and Jedi's point all along ?

[goboatingnow]

Originally Posted by boatpoker

Am I reading this correctly ? Their ball valves a nd throughulls are both parallel threads and they use bronze not brass ?

Has not that been ABYC and Jedi's point all along ?

No this manufacturers has both DZR and bronze certified to ISO standards but they recommend bronze.

Many EU manufacturers use mushroom bronze. Nobody I know fits flanged fittings.

The point is “ good” quality DZR and bronze meet ISO specs. But the reality is that good quality DZR is as expensive to certify as bronze ( iso now has separate tests for DZR )

The tread issue is being confused. Every U.K. plumber knows that copper compression is a parallel and taper Thread mix, the fitting engages about 80% of available thread depth and then seals. Mind you I always add Ptfe tape. !!!

[deblen]

Originally Posted by Pete7

Nick, don't think I have ever seen a tapered valve or through hull. ASAP are one of the major suppliers on line in the UK.

https://www.asap-supplies.com/produc...mm-long-403105


https://www.asap-supplies.com/produc...e-ports-405705

I followed these 2 links.
Both the skin fitting & valve are specified as BSP thread.
Is this BSPT or BSPP??. There is mention of internal BSP & external BSP.
Can you explain to me what I should assume if I see BSP without a following P or T.
Does " internal" or "external" in the thread specs tell me something about whether the threads are Parallel or Tapered?
I fully accept that BSP threads are all the same pitch,thread angle & diameter & that Tapered & Parallel fittings can be screwed together a few threads because of this matching pitch,thread angle & diameter-just like NPT & NPS.
Just trying to understand EU terminology. Tks/Len

Goboatingnow
Lets not mix brass tubing fittings in with a discussion about iron pipe fittings.
Tubing fittings are a totally different kettle.

[deblen]

Originally Posted by goboatingnow

No this manufacturers has both DZR and bronze certified to ISO standards but they recommend bronze.

Many EU manufacturers use mushroom bronze. Nobody I know fits flanged fittings.

The point is “ good” quality DZR and bronze meet ISO specs. But the reality is that good quality DZR is as expensive to certify as bronze ( iso now has separate tests for DZR )

The tread issue is being confused. Every U.K. plumber knows that copper compression is a parallel and taper Thread mix, the fitting engages about 80% of available thread depth and then seals. Mind you I always add Ptfe tape. !!!

"Every UK plumber" should google teflon tape on compression fittings(ferrule) or olive" fittings.

Never use any type of sealant on a compression fitting. If the fitting leaks,take it apart,cut a short length of tubing with old olive/ferrule off & install a new olive & reassemble. Better still,use flare fittings without sealant for any tubing joint except low pressure water.
You should use thread sealant/T tape on the BSPT portion of any tubing fitting because that is threading into a (tapered) iron pipe fitting.
Tapered pipe fittings are what thread sealant/Teflon tape is for.
Cheers/Len
https://blog.brennaninc.com/teflon-t...brass-fittings


https://plumbingwizard.org/ptfe-tape...sion-fittings/

[s/v Jedi]

Originally Posted by boatpoker

Am I reading this correctly ? Their ball valves a nd throughulls are both parallel threads and they use bronze not brass ?
Has not that been ABYC and Jedi's point all along ?

It’s absolutely f’ing unbelievable. I have been ridiculed, as was Rod Collins, the ABYC (which I regularly do for electric subjects but they are 100% correct on this issue) and US practice of using bronze and flanged valves. But we were absolutely correct and all the EU fanboy rhetoric was fake, untrue and based on ignorant opinion.

I’m still recomposing myself. This just shows that one should not give in when you know you are right. I can’t believe how people think a straight thread nut can be screwed all the way down a tapered thread fitting, or choose to quietly believe that because of how furious such ignorant statements are made!

I’ll be back, I want to summarize for those who want to know exactly how things are without reading through years of disinformation.

[Manateeman]

Jedi Master. The depth and breath of your expertise truly impresses us. The false information, personal attacks, sarcasm and attempts to derail the thread, will not nor cannot detract from the simple truths you have posted.
You post not just a personal opinion, but an INVALUABLE COMPENDIUM on this critical subject.
The manatee crew doffs their caps to you good sir, in gratitude for your learned contributions.
Captain Mark

[s/v Jedi]

From the little that has been shared from Maestrini (please share all the documents like promised, don’t hold back anything! We want to see the ISO installation test results and certificate of compliance like TruDesign shows etc. etc.) I am willing to believe they may pass tests when conforming to exact minimum and maximum hull thickness requirements, to be adjusted by backing plates (which was also ridiculed before), which means the following are allowable installations:

- for sizes 3/4” and up (not 1/2”) you can use the reinforced plastic components from TruDesign and Forespar. For TruDesign you -must- use their collared valves (https://www.trudesign.nz/marine/prod...earing-collars) and for Forespar you must use their flanged ABYC approved models (https://www.hodgesmarine.com/fsp9040...xoCtOIQAvD_BwE)

- you can use Maestrini fittings with their flanged valves. These come in properly matching BSPP thread so are conforming to ISO requirements. They also sell non-flanged valves with the proper BSPP thread that can be screwed on top of their skin fittings, but use of these has not been demonstrated yet to conform to side loading tests (unlike all the other options in this list).

- you can use Groco fittings with either their flanged valves or their flanged adapters, the latter which allow use of ball valves with tapered female thread. You can get these in NPS or BSPP thread and in bronze or stainless steel.
Groco also sells skin fittings with a combination thread that allows a NPT valve to be directly screwed onto it. I do not believe this is ABYC compliant but it can be used above the waterline, where I also use non-compliant Forespar plastic seacocks (requirements are for below waterline installation)

That’s it, nothing else has been shown to comply with safe installations.

What you certainly can not do:

- never mix BSPP with NPS thread. This mistake is often (!!!) made with 1/2” and 3/4” fittings which can be forced to screw together. Your boat may sink because of this malpractice.

- never mix NPS with NPT thread, nor NSPP with BSPT thread. These mismatches are not allowed and your boat may sink because of this malpractice.

- NPS and BSPP threads are not watertight. They require a sealing washer or O-ring or the use of a thread sealant. For underwater seacock installations, the use of a thread sealant is mandatory. Never use a tapered thread valve (not NPT and not BSPT) onto a skin fitting, even when that seems to create a water seal. You have only engaged one turn of thread which is not enough to guaranty a watertight installation and it completely lacks mechanical strength requirements. Your boat may sink because of this malpractice (and it is done often)

- Do not use brass components. Even though some special alloy types are allowed, there are countless low quality, fake, knockoffs being sold incl. in chandleries, that it’s simply not worth to play this Russian roulette. Buy bronze or buy the approved plastic fittings (TruDesign and certain Forespar types).

What is good about all that happened in these threads is that we finally know for sure how it all works and we can end years of disinformation on this forum. Do not believe anything written here unless links to documents prove it. TruDesign has proven that, by adding the load bearing collars, they now pass requirements for sizes larger than 1/2”.

If you have TruDesign valves without the collars, or in 1/2” size, then you are not compliant and your boat is not as safe as required.

If you have the Forespar plastic flanged seacocks sold everywhere that fail as shown in Rod’s testing, then you are not compliant and your boat is not as safe as required.

If you have brass fittings or valves then you run a high risk even though some compliant brass parts exist. Almost all brass parts for sale are not compliant and you run a very high risk of sinking when you use these.

When you are replacing valves or fittings then consider choosing for an installation that conforms to these safety standards instead of blindly replacing with same kind. These are primary systems on a boat and more important than which insurance policy you have.

[s/v Jedi]

Originally Posted by Manateeman

Jedi Master. The depth and breath of your expertise truly impresses us. The false information, personal attacks, sarcasm and attempts to derail the thread, will not nor cannot detract from the simple truths you have posted.
You post not just a personal opinion, but an INVALUABLE COMPENDIUM on this critical subject.
The manatee crew doffs their caps to you good sir, in gratitude for your learned contributions.
Captain Mark

Thank you, it sometimes takes the fun out of being on the forum but I just can’t let the disinformation stand when it can put people who read it in danger.

[Dockhead]

Originally Posted by s/v Jedi

. . . you can use Maestrini fittings with their flanged valves. These come in properly matching BSPP thread so are conforming to ISO requirements. They also sell non-flanged valves with the proper BSPP thread that can be screwed on top of their skin fittings, but use of these has not been demonstrated yet to conform to side loading tests (unlike all the other options in this list).. . .

Maestrini certify the non-flanged valve screwed directly onto the skin fitting as ISO 9093-1 compliant. That standard is much more complex than the ABYC standard, and includes side loading. I posted the relevant screenshot from the document, and also the statement of the manufacturer.

And that is the exact installation used by all of the world's greatest yacht builders -- Swan, Halberg-Rassey, Amel, Oyster, Contest, etc. etc. Yes, Maestrini sells also flanged sea cocks, but not a single high end European builder uses them as far as I know.

Because the unflanged assembly is ISO 9093-1 compliant and perfectly adequate, and simpler. Simple is always good when extra complexity is not required -- Mechanical Design 101.

OK, Nick, we get that you are convinced that you know better than Swan, Halberg Rassey, Contest, Amel, Oyster, Sweden Yachts, and their designers including Dykstra, German Frers, etc. etc. etc., and that they are all idiots who don't understand or recklessly disregard correct design of underwater fittings. Sure. But we are entitled to our own opinion, which might correspond to German Frers rather than Jedi. Sorry.

Which is no disrespect. As you know I appreciate what you post, and have learned a lot from it, particularly on electrical matters. I have downloaded and preserved your fuel system design, and different electrical system designs you have posted, which are brilliant. On the subject of underwater fittings, however, I think you just have an irrational, passionate prejudice. Probably something all of us suffer from on one subject or another. That's my humble opinion.

[boatpoker]

Originally Posted by Dockhead

And that is the exact installation used by all of the world's greatest yacht builders -- Swan, Halberg-Rassey, Amel, Oyster, Contest, etc. etc. Yes, Maestrini sells also flanged sea cocks, but not a single high end European builder uses them as far as I know.

-----------------

OK, Nick, we get that you are convinced that you know better than Swan, Halberg Rassey, Contest, Amel, Oyster, Sweden Yachts, and their designers including Dykstra, German Frers, etc. etc. etc., and that they are all idiots who don't understand or recklessly disregard correct design of underwater fittings. Sure. But we are entitled to our own opinion, which might correspond to German Frers rather than Jedi. Sorry.

1. The builders answer to their accountants and is why they prefer cheap home repair style valves.

2. I have three close friends who are successful NA designers. None of them have ever specified a specific type/brand or seacock, toilet roll holder or galley faucet or engine or transmission ............

[goboatingnow]

Originally Posted by deblen

"Every UK plumber" should google teflon tape on compression fittings(ferrule) or olive" fittings.

Never use any type of sealant on a compression fitting. If the fitting leaks,take it apart,cut a short length of tubing with old olive/ferrule off & install a new olive & reassemble. Better still,use flare fittings without sealant for any tubing joint except low pressure water.
You should use thread sealant/T tape on the BSPT portion of any tubing fitting because that is threading into a (tapered) iron pipe fitting.
Tapered pipe fittings are what thread sealant/Teflon tape is for.
Cheers/Len
https://blog.brennaninc.com/teflon-t...brass-fittings


https://plumbingwizard.org/ptfe-tape...sion-fittings/

Thanks I complete plumbed three houses over the years. Central central systems , hot cold domestics , waste et.

All my copper compressions use PTFE tape , actually use Ptfe “ gas “ tape

As yet I’m not aware of any leaks. The first house is 30 years old now.

I was trained by a plumber that used hemp and boss white. But the world has moved on

( note the tape is only used on the treads the olive still forms the primary seal )

[goboatingnow]

Originally Posted by boatpoker

1. The builders answer to their accountants and is why they prefer cheap home repair style valves.



2. I have three close friends who are successful NA designers. None of them have ever specified a specific type/brand or seacock, toilet roll holder or galley faucet or engine or transmission ............

Nonsense. European builders are subjected to detailed inspection by a third party body that body is certified as independent and approved to carry out the certification. It’s a legal requirement.

Beneteau for example has a whole department for CE compliance.

No boat builders in Europe use “cheap home style valves. “ yes sometimes yards , chandleries and uninformed owners replace such with domestic valves

A US NA is not legally obliged to design to any given standards. A EU NA is most certainly obliged to.

I used to know Ron Holland when his design office was in cork they were very aware of the required standards. Often they were building to not only the RCD , but often RINA or others. NAs often delegated key elements to specialised engineering design houses as well especially in systems design , etc. these design houses were acutely aware of the relevant standards.

[boatpoker]

Originally Posted by Dockhead

I don't think Swan or Contest or any of the other builders named, whose yachts sell for millions, will endanger the watertight integrity of the vessels they sell to save €20 or whatever per through hull. Do you?

Groco 1.5" = $268.

Beneteau 1.5" DZR** ball valve = $28.21

** Surveyed hundreds of Beneteaus, jeanneaus, Hanse and Bavarias' and never seen a
DZR ball valve only plated brass

(photo below) This price difference becomes critical when you build a boat with 22 throughulls like this 54' Jeanneau. Note they are plated brass valves and not marked as DZR. I've also seen the plans from many Euro designers as I've used these for tonnage measurements and have never seen seacock or valves specified. If you think designers are specifying valves you are sadly mistaken.