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Discussion Starter #1
Hi there,

I just have a quick question regarding fuel systems and the standards put out by the ABYC. I'm going to be redoing a few sections of my fuel system, including a manifold for distribution to the main components (the engine, polishing system, heater, pump). Having experience with hydraulics, I feel compelled to use the JIC 37 flare for this piece of hardware. I realize this is overkill, but 1) I already have a bunch of the fittings and solid tubing available and 2) have the experience to make a reliable system 3) I enjoy the safety factor involved with overkill. Dont worry, I realize it is important to maintain flexible hose for the manifold to engine connection.

I have access to 316 stainless tube for the fuel. ABYC puts out a rule that states something along the lines of (this is the Transport Canada version, but you get the idea):

7.4.4 Every metallic fuel line:

1.shall be made of seamless annealed copper, nickel-copper, or copper-nickel;
2.shall have a minimum wall thickness of 0.75 mm (1/32 in); and
3.shall be galvanically protected from the structure in aluminum hulls.

I realize they dont make rules to cover every situation - but is there an actual reason why they dont specify stainless steel as OK, or am I just overthinking it?

Thanks for any input.

Cheers
 

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There are some justifications for the requirement, but for these purposes it doesn't really matter what they are. If you use tube and it doesn't comply with the regulations the vessel is also out of compliance with USCG safety and environmental requirements. See http://www.uscgboating.org/assets/1/AssetManager/ABYC.1002.01.pdf pg 52.

Frankly the preference is to move towards hose instead of tubing because of concerns over vibration, and the difficulty in properly supporting tube.
 

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Discussion Starter #3 (Edited)
OK - I get the standard. But can you please explain to me these supposed justifications. I'm not interested in the 'because' rule, but rather why?

The JIC standard is used on massive pieces of machinery around the world. It is in many ways similar to the AN standard, which is what is used in the very vibration prone world of aviation.

I'm not questioning the 'move to hose' either. For my specific purpose, tubing makes more sense right now. 'They' seem to have no problem with solid tubing either. Why no spec on stainless? I see some of the polishing systems (such as the FilterBoss) have stainless tubing. Does installing one of these bring ones boat out of compliance?
 

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OK - I get the standard. But can you please explain to me these supposed justifications. I'm not interested in the 'because' rule, but rather why?

The JIC standard is used on massive pieces of machinery around the world. It is in many ways similar to the AN standard, which is what is used in the very vibration prone world of aviation.

I'm not questioning the 'move to hose' either. For my specific purpose, tubing makes more sense right now. 'They' seem to have no problem with solid tubing either. Why no spec on stainless? I see some of the polishing systems (such as the FilterBoss) have stainless tubing. Does installing one of these bring ones boat out of compliance?
My guess is that the prohibition has to to with the way stainless work hardens. I can't think of any other reason why it would be prohibited.

It may make more sense for you, but the instant it is installed the boat becomes illegal to operate in the US. Should you then have a fuel leak I would bet the insurance company would deny environmental coverage, and you could be help liable not only for the fuel leak, but also for operating a vessel out of spec.

I will look into it an see if I can come up with a better answer for you, since is don't like 'it's the rules' answers either.
 

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IMHO it's the work hardening aspect of stainless steel lines that make it a no-go for fuel, or any other tubing on a boat.

Look around, even mega-yachts of the 'cost is no matter' type NEVER use stainless pipes.
 

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Discussion Starter #6
So I'm curious, do systems like the FilterBoss (0 TO 180 GPH | Diesel Fuel Polishing Systems | Racor Dual Filter System | FilterBoss) which are spec'd with stainless tube bring a boat out of compliance? Seems strange that they would be selling such a product. Some builders are offering such systems included with various packages. Also seems strange that they would be sending out new boats out of compliance. Anyone aware of the reasons behind this?
 

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So I'm curious, do systems like the FilterBoss (0 TO 180 GPH | Diesel Fuel Polishing Systems | Racor Dual Filter System | FilterBoss) which are spec'd with stainless tube bring a boat out of compliance? Seems strange that they would be selling such a product. Some builders are offering such systems included with various packages. Also seems strange that they would be sending out new boats out of compliance. Anyone aware of the reasons behind this?
Stainless fittings aren't prohibited, just stainless tubing. Which is why I think it is a work hardening issue, not a corrosion or material compatability one.

Researching this I also looked at the Canadian rules which also prohibit stainless fuel lines, and LLoyds which do as well.

Unfortunately no one gives an explanation, just the rule.
 

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Discussion Starter #8
The FilterBoss system includes stainless tube, not just fittings. Sorry for pestering, I'm just wondering why this can be sold. I believe Hunter and a few other offer these systems as options in new builds as well. Perhaps a question for the manufacturer...
 

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The FilterBoss system includes stainless tube, not just fittings. Sorry for pestering, I'm just wondering why this can be sold. I believe Hunter and a few other offer these systems as options in new builds as well. Perhaps a question for the manufacturer...
The rules only refer to installed fuel lines, not subsystem lines. I have asked around, and I can't really get a good answer other than
1) work hardening
2) the difficulty in adding connections
3) galvanic problems

1) could be a real issue depending on installation method
2) proper workmanship should solve this, but flaring stainless is difficult so they may be prohibiting it to prevent bad workmanship
3) is covered by other rules on dissimilar metals.

If anything turns up I will pass it on, but for now the best I can say is if they are installed properly there doesn't seem to be a technical reason why, but thems the rules, and being out of compliance is against the law...
 

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My guess is that the prohibition has to to with the way stainless work hardens. I can't think of any other reason why it would be prohibited.

It may make more sense for you, but the instant it is installed the boat becomes illegal to operate in the US. Should you then have a fuel leak I would bet the insurance company would deny environmental coverage, and you could be help liable not only for the fuel leak, but also for operating a vessel out of spec.

I will look into it an see if I can come up with a better answer for you, since is don't like 'it's the rules' answers either.
I don't think it makes the boat illegal to operate as ABYC is not a legal requirement though your insurance company would likely be unhappily. Many insurance policies require meeting ABYC for modifications and might ask for some systems to be brought up to the standard though some may not.

Sent from my ADR6425LVW using Tapatalk
 

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I don't think it makes the boat illegal to operate as ABYC is not a legal requirement though your insurance company would likely be unhappily. Many insurance policies require meeting ABYC for modifications and might ask for some systems to be brought up to the standard though some may not.

Sent from my ADR6425LVW using Tapatalk
See... 46 CRF 182.130 below. This applies to non-commercial small boats as well as commercial. Though inspection isn't required.




Title 46: Shipping

CHAPTER I: COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)

SUBCHAPTER T: SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS)

PART 182: MACHINERY INSTALLATION

Subpart A: General Provisions

182.130 - Alternative standards.

As an alternative to complying with the provisions of this part, a vessel of not more than 19.8 meters (65 feet) in length, carrying not more than 12 passengers, and propelled by gasoline or diesel internal combustion engines, other than a High Speed Craft, may comply with ABYC H-2, ABYC H-22, ABYC H-24, ABYC H-25, ABYC H-32, ABYC H-33, ABYC P-1, and ABYC P-4 (all eight standards incorporated by reference, see 46 CFR 175.600) as specified in this part.

[USCG-2003-16630, 73 FR 65207, Oct. 31, 2008]
 

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For what it's worth I finally got a reply from someone who was on the ABYC fuel system committee from the mid 90's to 2004. His reply was basically that the USCG prohibited stainless years ago in keeping with ABYC requirements. Once the USCG adopted the rules it has become almost impossible to change them, since the ABYC cannot permit that which the law prohibits.

Apparently rewriting this was looked at, but there were still not a consensus that stainless as a fuel line was safe, due to concerns over crevice corrosion, work hardening, cracking at the fittings, and galvanic corrosion. Though there seems to be plenty of evidence these concerns are minor.

In short, there doesn't seen to be a clear engineering prohibition, just a legal one. But that legal one does effect recreational boats.
 

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Discussion Starter #13
For what it's worth I finally got a reply from someone who was on the ABYC fuel system committee from the mid 90's to 2004. His reply was basically that the USCG prohibited stainless years ago in keeping with ABYC requirements. Once the USCG adopted the rules it has become almost impossible to change them, since the ABYC cannot permit that which the law prohibits.

Apparently rewriting this was looked at, but there were still not a consensus that stainless as a fuel line was safe, due to concerns over crevice corrosion, work hardening, cracking at the fittings, and galvanic corrosion. Though there seems to be plenty of evidence these concerns are minor.

In short, there doesn't seen to be a clear engineering prohibition, just a legal one. But that legal one does effect recreational boats.
Thanks for your time and effort in tracking down this info.

Are you able to provide a little more insight and explanation into the whole sub system point you made? With the filterboss, the filters are used as your primary filters, so it is very much a part of the regular fuel route. But it can also be used as a polishing system.

Cheers
 

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Basically this rule only effects the delivery lines. But it doesn't effect fittings, or subsystems. So from the tank to the racor, from the racor to the engine, and any transfer lines between tanks. Once it gets to the engine you can use stainless, fittings, high preasure lines, ect.
 

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Discussion Starter #15 (Edited)
Just to clarify -

I was reviewing the USCG Boatbuilders Hanbook which references Title 33 CFR Part 183 Subpart J for its fuel requirements. The very first line mentions that these are the requirements for gasoline powered inboards. So am I to understand the rule regarding the fuel lines does not apply to our diesel engines then?

First sentence in the below link:

Fuel Systems - Introduction

Edit:

I also found the actual regulation which also states the laws are applicable to gas inboards - under the Applicability section.

http://law.justia.com/cfr/title33/33-2.0.1.8.44.html#33:2.0.1.8.44.10
 

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My limited understanding is that the sulphur traditionally found in diesel fuels, attacks stainless steel and makes stainless unsuitable for diesel systems.

Granted that two "new" reductions in sulphur content have happened in recent times, it is possible that the recommendation excluding stainless is just a legacy issue and now a moot point for US vessels.

I don't see work hardening as being an issue, that affects copper lines much more than stainless, and is the reason why copper lines are forbidden in automotive brake systems--where stainless is the standard metal, constantly being hit by expansions and still not work hardening at all.
 

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I have seen several sources indicating that one should not allow copper, zink or any compound containing them (brass) to come into contact with diesel.

If this is correct, how does this affect the fuel system standards being quoted in this thread when one is operating with diesel as a fuel?

I have some brass fittings in my diesel fuel system and always wonder if I'm hurting my engine. Not so far.

Any comments?
 

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Brass is ok as far as I know but do not attach brass fittings to an aluminum tank.
 
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