Feedback for remote fuel senders...what's wrong with this idea?

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Barking Sands

Barking Sands

Guru
Joined
Dec 24, 2019
Messages
886
Location
United States
Vessel Name
M/V Intrigue
Vessel Make
1985 Tung Hwa Senator
I have two custom 105 gallon tanks on either side of the Perkins. They are tucked up under the floor leaving only about 6 or 8 inches above the tank. The tanks appear to be well made and have provisions for sight tubes at the aft end of each tank with shut off valves for both upper and lower portions of sight tubes. Fairly straight forward. To install a typical sender would require a ton of work and fuel logistics (both a re 3/4 full)

What I am contemplating is fabricating a 3.5 inch cylindrical tank the same height as the main tanks (maybe 16 inches tall). The top of the cylindrical tank will have provisions to mount a fuel quantity sender. The cylindrical tank will also have a lower and upper boss to connect fittings to the lower and upper fittings on the main tank where the sight tubes currently hook up. Removing sight tubes and plumbing in the tank using appropriate standards and methods and materials. Gauge hook up is pretty straight forwards from there. I imagine the quantity of these two cylindrical tanks would be around a gallon give or take. Accuracy can be adjusted by raising or lowering the cylindrical tanks in relation to the main tanks. Maintenance to the system/senders would be greatly simplified. Quantity readings should be very stable since the fuel needs to flow through small hoses as levels rise/fall. No real sloshing in a 3.5 tube.

What's wrong with this picture? Why isn't this done more routinely? There must be something wrong with the plan that I am overlooking.

The only thing I can see is the additional failure points. But using quality materials and practices that really should be negligible.

Feed back is of course much appreciated.
 
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That sounds like a good plan. I personally hate sight tubes for fuel or water, you can never see through them after they are in place for a few years. If you have the room, your plan sounds good.

pete
 
If I'm following, you would create a "float tank" that's like a sight gauge, but is opaque, and instead has some sort of float or other level sensor in it. And you are doing this because you don't have sufficient access to the tank to add a sensor?


If your are looking for easy, consider teeing a pressure sensor off the lower sight glass fitting. Then use a maretron pressure converter (FPM-100) and display to show calibrated fuel level. No tank fabrication of other plumbing required. The Maretron stuff, especially if you are creating a network for the first time, isn't cheap. But neither will be fabricating float tanks.
 
Barking Sands said:
What's wrong with this picture? Why isn't this done more routinely? There must be something wrong with the plan that I am overlooking.
Click to expand...

1. It would cost the builder a few more dollars than just having sight tubes.
2. It violates KISS.
3. Since I am in the engine room every day while cruising, and I know that I burn about 1 gallon per hour, I really don't need a remote gauge. I burn about 1/8th inch per hour on my 17" sight glass. So an 8 hour day is a one inch drop. Switching tanks would be a one inch drop the next day on the other tank. A sender and a remote gauge probably wouldn't even register this minute change, but easy to follow using a movable marker on the sight tube.

My sight "glasses" (actually clear vinyl tubing) were really discolored when I purchased. Probably 40 year-old tubing. I couldn't just lift the engine hatch and get a reading. (I might have been able to if I had painted the background, i.e., the tank, white.)

I bought a couple dollars of tubing at Home Depot. Disconnect the top, blow air into the tube to push the diesel back in the tank, turn off the valve, replace the tubing. That 10 minute job has been good for 3 years.

Personally, I wouldn't put in an electrical remote sender even if it were a 10 minute job and cost a couple dollars. My boating mantra is to avoid electrical gadgets whenever possible. So far, my vision is still more reliable than my electrical skill.
 
twistedtree said:
If I'm following, you would create a "float tank" that's like a sight gauge, but is opaque, and instead has some sort of float or other level sensor in it. And you are doing this because you don't have sufficient access to the tank to add a sensor?


If your are looking for easy, consider teeing a pressure sensor off the lower sight glass fitting. Then use a maretron pressure converter (FPM-100) and display to show calibrated fuel level. No tank fabrication of other plumbing required. The Maretron stuff, especially if you are creating a network for the first time, isn't cheap. But neither will be fabricating float tanks.
Click to expand...

I agree, this is the better approach. Since you have the bosses already installed you could also add a sight tube if you wanted a quick way to do a visual check when filling for example.
 
The old standard tank sender worked perfectly in my old Albin. There was no need for more accuracy or complication. I could look at the gage and predict within about 10% how much fuel I could take on.
 
Pete Meisinger said:
That sounds like a good plan. I personally hate sight tubes for fuel or water, you can never see through them after they are in place for a few years. If you have the room, your plan sounds good.

pete
Click to expand...
Thanks Pete. Much appreciated.
 
twistedtree said:
If I'm following, you would create a "float tank" that's like a sight gauge, but is opaque, and instead has some sort of float or other level sensor in it. And you are doing this because you don't have sufficient access to the tank to add a sensor?


If your are looking for easy, consider teeing a pressure sensor off the lower sight glass fitting. Then use a maretron pressure converter (FPM-100) and display to show calibrated fuel level. No tank fabrication of other plumbing required. The Maretron stuff, especially if you are creating a network for the first time, isn't cheap. But neither will be fabricating float tanks.
Click to expand...

The tank would be 5052 aluminum tube with end caps welded in. Then two bosses welded in the top and bottom sides. The top cap would have the opening made already for the sender to bolt right in.

The Maretron idea is a good one. I will have to look into that. Especially since I have an entire Garmin system going in soon and I will be adding a network. Ill have to check it out. Thanks a bunch.
 
Marco Flamingo said:
1. It would cost the builder a few more dollars than just having sight tubes.
2. It violates KISS.
3. Since I am in the engine room every day while cruising, and I know that I burn about 1 gallon per hour, I really don't need a remote gauge. I burn about 1/8th inch per hour on my 17" sight glass. So an 8 hour day is a one inch drop. Switching tanks would be a one inch drop the next day on the other tank. A sender and a remote gauge probably wouldn't even register this minute change, but easy to follow using a movable marker on the sight tube.

My sight "glasses" (actually clear vinyl tubing) were really discolored when I purchased. Probably 40 year-old tubing. I couldn't just lift the engine hatch and get a reading. (I might have been able to if I had painted the background, i.e., the tank, white.)

I bought a couple dollars of tubing at Home Depot. Disconnect the top, blow air into the tube to push the diesel back in the tank, turn off the valve, replace the tubing. That 10 minute job has been good for 3 years.

Personally, I wouldn't put in an electrical remote sender even if it were a 10 minute job and cost a couple dollars. My boating mantra is to avoid electrical gadgets whenever possible. So far, my vision is still more reliable than my electrical skill.
Click to expand...


I understand your POV completely. Getting down in my area to open both upper and lower and port and stbd valves is a bit of a PITA. But I do want to keep is somewhat simple. Having two gauges that can be left on at anchor or even in the slip to eyeball and of course while underway is appealing to me not only for monitoring general fuel burn but also to monitor for sudden loss of quantity to alert for some issue like a fuel leak.
 
Airstream345 said:
I agree, this is the better approach. Since you have the bosses already installed you could also add a sight tube if you wanted a quick way to do a visual check when filling for example.
Click to expand...

I agree. I will have to look into the Maretron.

Anyone have experience with the accuracy of the Maretron?
 
jleonard said:
The old standard tank sender worked perfectly in my old Albin. There was no need for more accuracy or complication. I could look at the gage and predict within about 10% how much fuel I could take on.
Click to expand...

If I make the stand alone tanks myself..the old standard gauges and senders are around $50 each x 2= around $100. The materials for the tanks would be less than $200 (aluminum is getting pricey). I am pretty sure achieving 10% will be easy given I can adjust the remote tanks higher or lower in relation to the main tank they measure. Obviously the LOW end is what's more important.

For those Pilots here...you would be surprised at the methods used and shortcoming to calibration of aircraft fuel quantity systems...lol. Those systems are not that accurate.
 
Pete Meisinger said:
That sounds like a good plan. I personally hate sight tubes for fuel or water, you can never see through them after they are in place for a few years. .
Click to expand...

You must be doing it wrong
Ours are at least 20 years old and still clear.

I would never go electric
KISS
 
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Maretron system looks pricey. Alternatives aside, are there any oversights or excessively dangerous issues with the originally described plan?

Obviously when I fab the cans/tanks they will be pressure tested etc.
 
If I understand your setup you could consider the Tank Tender system. An elbow on the bottom valve, a TEE on the top valve. Hose, pipe or sight glass tubing between the lower elbow and upper TEE. A plug drilled and tapped to accept the tank tender's fitting on the top of the TEE. Simple, no additional tank to build, fit and fail. Valves that already have been installed to shut off the not installed sight glasses could be used in the event of a leak.

Can be used for potable and black water tanks as well, all in one display panel.

http://tanktender.com/

Not as inexpensive as your proposed system but simplier and easier to install.

No affiliation with the company, just a happy customer. If you go that way buy direct from Tank Tender for outstanding support.

Barking Sands said:
provisions for sight tubes at the aft end of each tank with shut off valves for both upper and lower portions of sight tubes.
Click to expand...
 
I'm unclear if the OP simply wants remote monitoring, or if sight-tubes would be okay but has concerns over their construction. If the latter, there are some excellent quality sight-tubes for industrial applications. The tubes are usually either polycarbonate or uber-glass and will not yellow like Vinyl will. They are well-protected in billet-machined aluminum blocks, and are configured to enhance accurate viewing. I think I paid around $150/ea for mine about 5-years ago.

https://www.ldi-industries.com/LDI/Reservoir-Accessories/Sight-Gage-Closed-Circuit.htm

I'm sure its gotten better over the years, but I don't recall seeing many marine dashboard-mounted fuel-level displays that were trusted. Many were dead; many inaccurate, perhaps due to improper calibration in the first place. Regardless, tough to beat a sight gauge, though those too must be calbirated.

Peter
 
mvweebles said:
I'm unclear if the OP simply wants remote monitoring, or if sight-tubes would be okay but has concerns over their construction.
Peter
Click to expand...
Remote monitoring is the reason. Sight tubes are working fine but its a pain to get down and open the 4 valves.
 
Maybe a camera in the engine room? Could be as simple as a "Nanny Cam" viewed on your phone; or as robust as a purpose-built engine room camera viewed off your MFD.

Good luck -

Peter
 
Way too complex solution for a simple task. If you don’t like the location of the sight tube you can extend them horizontally almost anywhere. Open two valves and gravity. You only need one tube port one tube starboard.
Clean or replace Tygon tubing every couple years for maybe $20
The only thing simpler is a dip stick.
 
High Wire said:
Way too complex solution for a simple task. If you don’t like the location of the sight tube you can extend them horizontally almost anywhere. Open two valves and gravity. You only need one tube port one tube starboard.
Clean or replace Tygon tubing every couple years for maybe $20
The only thing simpler is a dip stick.
Click to expand...

What I propose does not seem complex at all. Its quite simple from my perspective. Lengthening the tygon doesn't really help. Its the location of the valves. I also want continuous monitoring with out opening a hatch.
I also don't really like having fuel in Tygon with valves open for any length of time unmonitored.

I really just want to know if there are any fatal unforeseen issues.
 
Simi 60 said:
Why do you need to turn them on and off?
We could, but never have
Click to expand...

This is one thing that is not acceptable for me. Tygon with clamps squeezed around a barb or nipple. We have ABYC mandates for fuel supply lines that are feeding engines...even if only by gravity. But Tygon on a tank sight tube that's left open for long periods? I have replaced hundreds of broken Tygon tubes on aircraft that are moderately aged (always at the clamp). Tygon and the like is only used on aircraft for drain lines to route to a common gang drain. Not to be trusted otherwise. This of course is my opinion.

On our Jet A storage tanks which has sight tubes that are left open they are of the hard clear fibrous material that is impact resistant.

The want/need for this modification is really two fold.
1) I dont like leaving the valves to the sight tubes open for long periods.
2) I want to remote monitor fuel level from the helm

But the main reason for the post is for you smarties to point out the fatal flaw..lol.
 
Last edited:
What's wrong with red dyed diesel in a boat?
 
Barking Sands said:
This is one thing that is not acceptable for me. Tygon with clamps squeezed around a barb or nipple. We have ABYC mandates for fuel supply lines that are feeding engines...even if only by gravity. But Tygon on a tank sight tube that's left open for long periods? I have replaced hundreds of broken Tygon tubes on aircraft that are moderately aged (always at the clamp). Tygon and the like is only used on aircraft for drain lines to route to a common gang drain. Not to be trusted otherwise. This of course is my opinion.

On our Jet A storage tanks which has sight tubes that are left open they are of the hard clear fibrous material that is impact resistant.

The want/need for this modification is really two fold.
1) I dont like leaving the valves to the sight tubes open for long periods.
2) I want to remote monitor fuel level from the helm

But the main reason for the post is for you smarties to point out the fatal flaw..lol.
Click to expand...

I don’t see any reason to not do this. Gauges and senders are cheap and easy to source and troubleshoot. There’s no fire hazard, and if you leak test the gauge tank and do a proper installation it will work fine. I had an electric sender on my last boat that worked consistently for the 30 years I owned it.
Obviously, any penetration in the fuel tank is a potential point of failure, but if done properly, and engineered by you so easy to understand, should be perfectly safe.
 
I have a 200 gallon day tank with a sight tube. The valves haven't been closed for 11 years w/o problems. But I live aboard and have sensors.

Also a day tank supplies the engines and fuel from side tanks are pumped into it as needed. It solves all the problems of too much fuel on one side.
 
Thanks for all the replies and input. I will make the set up and report back.
 
Barking Sands said:
I understand your POV completely. Getting down in my area to open both upper and lower and port and stbd valves is a bit of a PITA.
Click to expand...

as Simi has said, many leave all 4 valves (2 tanks) open all the time. If you have concerns about leakage, you can still leave the top valves open 24/7 safely. ER check: open the lower valve, instant reading of fuel, close valve. For those who don't like the gradual yellowing of PVC tubing, Mc Master-Carr has some very nice but pricey food grade and fuel rated tubing that resists virtually everything!
 
I did exactly what you are saying

Barking Sands said:
I have two custom 105 gallon tanks on either side of the Perkins. They are tucked up under the floor leaving only about 6 or 8 inches above the tank. The tanks appear to be well made and have provisions for sight tubes at the aft end of each tank with shut off valves for both upper and lower portions of sight tubes. Fairly straight forward. To install a typical sender would require a ton of work and fuel logistics (both a re 3/4 full)

What I am contemplating is fabricating a 3.5 inch cylindrical tank the same height as the main tanks (maybe 16 inches tall). The top of the cylindrical tank will have provisions to mount a fuel quantity sender. The cylindrical tank will also have a lower and upper boss to connect fittings to the lower and upper fittings on the main tank where the sight tubes currently hook up. Removing sight tubes and plumbing in the tank using appropriate standards and methods and materials. Gauge hook up is pretty straight forwards from there. I imagine the quantity of these two cylindrical tanks would be around a gallon give or take. Accuracy can be adjusted by raising or lowering the cylindrical tanks in relation to the main tanks. Maintenance to the system/senders would be greatly simplified. Quantity readings should be very stable since the fuel needs to flow through small hoses as levels rise/fall. No real sloshing in a 3.5 tube.

What's wrong with this picture? Why isn't this done more routinely? There must be something wrong with the plan that I am overlooking.

The only thing I can see is the additional failure points. But using quality materials and practices that really should be negligible.

Feed back is of course much appreciated.
Click to expand...

I have 1/2 valves, top and bottom of my two tanks. My son works for an automotive fabricator and just so happens to always have nice stainless scrap that he has accumulated over the years. Sat down with my welder and in about an hour had 2 very nice canisters that held KUS resistance fuel sensors. Hook those up to my Garmin network and have very accurate fuel gauges available on my Garmin heads.
 
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