Fuel Tank Sight Glass Material

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On my AT the tanks are rectangular. I know the total capacity, I know all the measurements. I took a piece of blue tape, stretched it out and wrote the levels and capacity for each inch. I then stuck to the tank next to the sight glass. It might not 100% correct but, it appears to be more accurate than my super duper remote reading system.
 
I worked thru some numbers on thermal expansion of possible site glass systems:

These numbers use a 48" high diesel tank, ran the numbers of 2 different tank materials, and incurring a thermal change of 60 deg F. I'm going to use all US units of measure.

The thermal change simulates an empty tank that is filled with 50 deg F fuel; Then incurs a running temperature some time later of 110 degrees. Note it is the site tube temperature here that will become critical, which is quite easily and quickly heated by the ER.

The steel tank will itself expand to 48.02" high. An aluminum tank will expand to 48.03". A glass site tube will expand to 48.01" long. All these are small, non-damaging numbers. But, lets look at the expansion of trapped diesel within the site tube, bounded by shut-off's top and bottom.

Diesel has a vastly higher coefficient of expansion, than the materials so-far described. The warmed diesel trapped within the 48" tube is now a whopping 49.3" tall! If there is no air space within that 48" tube, it WILL break. I have not read the ABYC ship standard, but I would have a hard time accepting a glass system with a top shut off, without any kind of overpressure relief.
 
diver dave said:
I worked thru some numbers on thermal expansion of possible site glass systems:

These numbers use a 48" high diesel tank, ran the numbers of 2 different tank materials, and incurring a thermal change of 60 deg F. I'm going to use all US units of measure.

The thermal change simulates an empty tank that is filled with 50 deg F fuel; Then incurs a running temperature some time later of 110 degrees. Note it is the site tube temperature here that will become critical, which is quite easily and quickly heated by the ER.

The steel tank will itself expand to 48.02" high. An aluminum tank will expand to 48.03". A glass site tube will expand to 48.01" long. All these are small, non-damaging numbers. But, lets look at the expansion of trapped diesel within the site tube, bounded by shut-off's top and bottom.

Diesel has a vastly higher coefficient of expansion, than the materials so-far described. The warmed diesel trapped within the 48" tube is now a whopping 49.3" tall! If there is no air space within that 48" tube, it WILL break. I have not read the ABYC ship standard, but I would have a hard time accepting a glass system with a top shut off, without any kind of overpressure relief.
Click to expand...

Oh, great. There you go bringing SCIENCE into the discussion........:D
 
Rufus said:
Markel now allows customers to do their own recurrent insurance surveys. This surveyor nonsense needs to stop. Complain to your insurer. And as stated earlier, ABYC is a recommended guideline for new construction.
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My surveyor cited fire safety regulations that were not ABYC, but some other body/authority. He felt those regulations were binding.

Jim
 
JDCAVE said:
My surveyor cited fire safety regulations that were not ABYC, but some other body/authority. He felt those regulations were binding.

Jim
Click to expand...


I personally think you should tell your surveyor to lighten up or you will shove that tubing up his tight arse.. then he'll be glad its plastic and not glass.
Too often surveyor's get hung up on personal views vs actual requirements for the year the vessel was mfg.

Just tell him its a self extinguishing system, in a fire that will melt the plastic sight tubes the bilge hoses will also melt causing water intrusion that will put out the fire
Hollywood
 
1989 H-33 ABYC diesel tank:

g. All individual components of the fuel system as installed in the boat shall be capable of
withstanding a 2 1/2 minute exposure to free burning fuel (N-Heptane) or No.2 Diesel Fuel
without leakage.
EXCEPTION 1. Portions of fuel distribution systems, if a break at any point in this system will result
in the discharge of no more than 5 ounces of fuel in 2 1/2 minutes including
fuel that may drain from the engine. See ABYC H-33.10.c. which precludes the
use of non-fire resistant hose for fuel retum lines.
EXCEPTION 2. Self-draining fill and vent pipes located in a separate compartment from the
engine compartment.
EXCEPTION 3. Fill and vent extemal fittings.

150 seconds of fire exposure is going to be an onerous test for the plastics we have brought to the table. The 5 oz rule is interesting. If this "fuel distribution" description can be carried to a site gauge (I'm doubtful). Just make the tube skinny.

I'm sure all reading this have the required warning placard near the tank(s)??
"WARNING--close both site gage valves unless reading the level" ??

Plastic melts, glass shatters spontaneously. hmmm. I'm out of ideas, expect I have very good luck with magnetic reed switch tank sensors (GEMS, ISSPRO etc):whistling:
 
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My tank has a small ball valve at the outlet and a long plastic hose that runs up the side of the engine room door. You open the valve then the fuel finds its own level in the tube then you shut it off again. There is a scale adjacent. No fire risk, no spill risk (well, maybe a cup full) and every 10 or 20 years you change the tube. Not that difficult. The tube is open to the air but it is so small there is no smell.

There is a real risk of over-engineering this. Diesel will not ignite unless there is an open flame so before this tube melts you already have a problem, my two automatic extinguishers should deal with that problem, otherwise the dinghy will do it.

All that ABCDYC stuff only applies to new builds and is only suggestions - just use common sense and good practises.
 
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I used clear tubing with braid it has been in there for probably 6 years, a bit of stain but still easy to see the fuel level. Easy to change too, my method, maybe everyone does it this way.
Change when 3/4 full or less, remove top clamp, open bottom valve, blow into the top of the tubing to push the diesel back into the tank, shut bottom valve. Remove bottom clamp and replace the tubing.
 
I have a Tank Tender system that works very well for fuel and water tanks.

My simple solution to the problem with the surveyor would be to remove the site tubes and put a plug in the valves. Then have him inspect and change the report. What you do after the insurance company signs off is up to you.

Ted
 
I have a deck fill on each of my 150 gallon saddle tanks. I have a stick, pine I believe but it may be oak or ash, maybe even poplar..not sure, but I have been thinking of upgrading to teak.
The stick is marked off with lines. The line closest to the end I poke into the thru hull to the bottom of the tank is marked 1/4 next in the middle is 1/2 then next is 3/4 I swag full or 1/0.
My surveyor overlooked the fact it was not teak. Guess I am good!
 
Thanks everyone for your help on this. I've done more research and it seems I'm compliant.

I asked my surveyor what rules does Transport Canada follow concerning fuel systems for pleasure craft and he said that they follow ABYC. After my research and consultation with a respected marine consultant, here is what ABYC says about fuel gauges generally and fuel sight gauges in particular:

33.5.8 A means to determine fuel level or quantity shall be provided.

33.5.8.1 If a sight gauge is used;

33.5.8.1.1 it shall be equipped with a shutoff valve at the top and at the bottom of the gauge, and

33.5.8.1.2 a warning label shall be placed adjacent to the sight gauge, and

33.5.8.1.2.1 the warning label shall comply with the requirements of H-33.16.

file:///d:/Documents/Boats/ABYC%20Diesel%20fuel%20systems_2005.pdf

Note that the regulations do not "identify" type of material accepted for use in sight tubes. This was pointed out to me by the "respected marine consultant". What's more interesting is the solution suggested to me by my surveyor uses gate valves, which I was advised SHOULD NOT BE USED FOR FUEL SYSTEMS.

So I looked the subject further and came up with detailed schematics on sight gauges from John Moncrieff.
https://www.johnmoncrieff.co.uk/wp-content/uploads/2017/08/G22-Quickmount-Datasheet.pdf
They use either borosilicate glass or acrylic tubes in their sight gauges.

I have scoured the web and find that acrylic and borosilicate glass are used for sight tube material. Each have their advantages and disadvantages. Glass is more tolerant to high temperatures, but of course is less tolerant of pressures and mechanical shock, as compared to acrylic which is less tolerant to high temperatures, but more tolerant of pressures and mechanical shock.

A product which is not discussed is Teflon tubing. Teflon tubing is temperature rated to 260 C (source: PTFE Tubing (PolyTetraFluoroEthylene) from NORELL®), higher than acrylic which is rated to 143-148 C (280-290F, source: https://www.copeplastics.com/polycarbonate-tubing.html).

So why not use Teflon? You can fry eggs on teflon frying pans. I can easily source Teflon although it’s considerably more expensive than polyethylene, it’s still a more affordable solution than industrial sight gauges that may not be easily retrofitted into existing tank/engine room situations. If there is a rigidity issue with Teflon (it’s highly flexible) it can be shielded in aluminum pipe, with milled grooves for reading.

All I have for now.

Jim
 
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Tell your surveyor, the boat was in compliance with the rules and regulations when the boat was constructed.

I had a minor question from my surveyor when he said there was no fan drawing fumes from the engine room prior to starting the engine.
I told him, it was not required in a diesel powered boat plus, my AT was in compliance with all the rules and regulations when the boat was constructed in 2008. That satisfied him.
 
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Teflon AF; virtually clear. temps to over 550 deg F. New to me. :thumb:


AF is from a resin company. Now the simple matter of finding someone making tubes out of it.
 
diver dave said:
Teflon AF; virtually clear. temps to over 550 deg F. New to me. :thumb:

AF is from a resin company. Now the simple matter of finding someone making tubes out of it.
Click to expand...


Well, what’s wrong with barb fittings and hose clamps together with the flexible Teflon hose?

I have a sample for a different use and you can easily see coloured fuel through it. Plus it’s very stable for use with multiple fluids, with the exception of “molten” caustics I believe. Not what we have in fuel tanks.

“Please do be aware, however, that PTFE reacts with fluorine, molten sodium hydroxide and molten alkali metals.”
 
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JDCAVE said:
I asked my surveyor what rules does Transport Canada follow concerning fuel systems for pleasure craft and he said that they follow ABYC.
Click to expand...

Call Transport Canada. I don't believe that they require ABYC compliance for old construction. If they do, they're way out of line. I know for a fact that they follow the same procedures for aircraft as the FAA....safety requirements at the time of initial construction apply unless there is a supplementary directive (airworthiness directive) issued to correct a specific problem on a specific model of machine. Enforcing later requirements is unduly burdensome...and the machine was deemed safe when is was approved for import (in this case). It was safe then, and it's safe now. By the way, removing the system to get through a survey does nothing to address this pervasive problem. The insurance companies need to understand that their expensive hired gun surveyors are out of order and that knowledgeable owners can provide the necessary information to satisfy a piss ant insurance survey.
 
JDCAVE said:
My surveyor cited fire safety regulations that were not ABYC, but some other body/authority. He felt those regulations were binding.

Jim
Click to expand...

"Your boat when constructed it was in compliance with all existing rules and regulations."

Does the surveyor have specific recommendations and a cousin who will implement those recommendations?

Appeal to your insurance company.
There is more than one surveyor and insurance company.
 
OldDan1943 said:
"Your boat when constructed it was in compliance with all existing rules and regulations."

Does the surveyor have specific recommendations and a cousin who will implement those recommendations?

Appeal to your insurance company.
There is more than one surveyor and insurance company.
Click to expand...

I won't quote verbatim but he indicates that fuel level hoses should be replaced with an approved gauge and the sentence was approximately that brief. I think the "boat when constructed" clause may not apply in this situation as the fuel tanks are not original construction, having been replaced with aluminum.

BTW, I am not aware of gauges that are certified as being AYBC compliant. Anyone?
 
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OldDan1943 said:
Tell your surveyor, the boat was in compliance with the rules and regulations when the boat was constructed.
Click to expand...

+1

Adding a valve at the top of my sight gauge was a recommendation by my surveyor when the boat was surveyed. It was not listed as a required safety or regulatory issue. Hence my insurance company didn't even mention it. Not so the leaking propane system or inoperable starboard running light.
 
Simply write a note to your insurance company that says “Fuel sight gauges have been brought in to compliance with ABYC regulations 33.5.8 and should no longer be considered an issue.”

You can’t tell a surveyor to change his report and you can’t tell the insurance company to ignore the surveyor after all you picked him. You can work around the surveyor’s idiosyncrasies by reporting the truth that is spun in your favor. It’s not your fault if the insurance company interprets this as you just made an update to your system.
 
tiltrider1 said:
Simply write a note to your insurance company that says “Fuel sight gauges have been brought in to compliance with ABYC regulations 33.5.8 and should no longer be considered an issue.”
Click to expand...

I like it. I think I would refine that somewhat to read;

“Fuel sight gauges now comply with ABYC regulations 33.5.8. Thank you for bringing this potential problem to my attention."
 
A fine point detail regarding ABYC.... The ABYC standards are frequently referred to as rules, regulations, codes, and other terms that imply a regulatory or binding legal requirement, none of which accurately describe the ABYC Standards and Technical Information Reports. The ABYC standards, as others have pointed out, are not enforceable regulations, but rather standards that builders voluntarily adopt.

As for the tubing, I replaced the sight tubes on my fuel and water tanks with Tygon SE-200. The OEM tubing was discolored and almost impossible to view the tank levels. The Tygon tubing is now 11 yrs old, it's still crystal clear, and has held up well. The water tanks are in the lazarette and are frequently subject to abuse with no problems. The tanks have a ball valve on the bottom of the tube, none on the top. Absence of the top valve hasn't ever been dinged on a survey, certainly easy enough to remedy if it would be. The valves on the fuel tanks are always closed unless checking the level.

Borosilicate glass tube is certainly durable enough to be used in pressure steam sight tubes, but I certainly wouldn't want glass in a marine fuel tank application. Simply too much potential for breakage. If the fuel mess wouldn't be enough, the glass shards would be worse yet. Just doesn't seem to be a prudent application for glass.
 
I had always wondered how to secure the sight tube from something hitting it under way and decided the best low cost way to shield the sight tube was with a shelf rail (like many people use in a pantry or closet) since it is sturdy, inexpensive, readily available and shaped in a channel that could be slid around the tube and secured from the back. You would still have the front of the tube visible but would be a harder target for an accidental hit if something moved around underway.

That plus having valves at both ends.

Having an open ended sight tube may not read right if you have positive or negative pressure on the engine room while underway. When you open the bottom tank sight tube valve, the positive pressure or vacuum could sway the results in the tube. By having two valves and venting the top back to the tank, it should be vented outside and neutral to any ER pressure / vacuum issues.

I also read somewhere that spring loaded valves were not ABYC since heat might make the spring lose it's tension... fading memory.
 
Ah, that's my problem, "fading memory". My spring is losing its tension so my past memories and knowledge are falling out my bottom.
 
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Further update: I still haven’t committed to the use of Teflon yet. It’s a little more complicated than I had thought. The sample of tubing I had was silicon, not Teflon. Silicon is not a suitable material. It turns out that Teflon is more rigid and a compression fitting is required. In order to complete this retrofit with ball valves, I will have to bring the valve assembly further out from the tanks, which would require a longer pipe from the coupling on the tank. Access to the existing pipe is a bit problematic as it’s all insulated up. Further planning required.

I did a test with the sample I was given. The fuel is clearly visible through the Teflon tube. It’s quite rigid but still flexible enough for adjustments. It’s also much more tolerant to mechanical shock than acrylic.
 
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What a run around! My surveyor would not accept the Teflon. Because of my particular situation, he felt it would need to meet Transport Canada Marine Regs. So I phoned Transport Canada Marine Inspection and asked about the gauges. Got a by the books officious gentleman on the like and asked what they wanted. Would they “approve” Teflon? They don’t approve Teflon but they would “accept” it. I guess there’s a difference. But they want self-closing valves. My surveyor would approve them together with the Teflon. He didn’t even know of such a valve. Go figure! I got 8 self closing 1/4” valves which will fit in with my existing fittings.

Economical Deadman Ball Valve.
http://www.sk-automation.com/ballvalves/deadmanhandle.html
http://www.sk-automation.com/images/tn_5210.pdf

I will use compression fittings. Although I could use quick push connect, I’m not sure if they are “code”.
 
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JDCAVE said:
What a run around! My surveyor would not accept the Teflon. Because of my particular situation, he felt it would need to meet Transport Canada Marine Regs. So I phoned Transport Canada Marine Inspection and asked about the gauges. Got a by the books officious gentleman on the like and asked what they wanted. Would they “approve” Teflon? They don’t approve Teflon but they would “accept” it. I guess there’s a difference. But they want self-closing valves. My surveyor would approve them together with the Teflon. He didn’t even know of such a valve. Go figure! I got 8 self closing 1/4” valves which will fit in with my existing fittings.

Economical Deadman Ball Valve.
Dead Man Ball Valve with Spring Return Handle
http://www.sk-automation.com/images/tn_5210.pdf

I will use compression fittings. Although I could use quick push connect, I’m not sure if they are “code”.
Click to expand...

Take the sight glasses out, close the holes off with plugs, when he approves your boat, get insurance, put the friggin sight glasses back on. Either that or you will have to marry his sister.
 
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My sight tubes are typically referred to as 'water gauges'. As the pic shows, they have brass rods either side of the tube. My invoice from the yard describes the components as follows.
- "Gauge water brz 1/2" with check PR"
- "5/8 x 3/8 x 6' sight glass tube plastic"

All supplied by Ballard Hardware (Seattle). The 'check' designation refers to some kind of internal mechanism to stem, if not stop, flow in the event of tube failure. Unfortunately I cannot be more definitive on tube material than 'plastic'.

I have not closed either the top or bottom valves on the sight tubes in the last 6 years. They are in a reasonably well protected location, and I do not have anything loose in the ER that could strike the tubes.

I have had the boat surveyed twice for insurance since the sight tubes were fitted, once in Seattle and once in Australia. Neither time has the surveyor asked about these sight tubes or made any comment on them. The yard in Port Townsend was very good regarding compliance with ABYC, so based on all this I am comfortable that what I have is acceptable.
 

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JDCAVE said:
I got 8 self closing 1/4” valves which will fit in with my existing fittings.
Click to expand...


Self closing valves? Who knew??? Not me... makes sense though. Hmmm...
 
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