Fuel tank level gauge

[ervonna]

Purchasing a boat that doesn’t have gauges for the fuel tanks. Any advice as to keeping up with the amount of fuel in tanks ? Or is it worth it to install fuel Gauges??
Thanks for any insights!

 

[NWSeadog]

I have developed a good idea as to how much my engine burns per hour. So, I use my hour meter to get an idea of how much is left in the tank and occasionally I'll dip the tanks to confirm that I'm on track. For me one thing about a diesel engine on a boat is that I never want to run dry. It can be a real pain to bleed the engine to get it to restart.

 

[HiDHo]

I feel your pain, first trawler also had no fuel gauge, but did have a dip stick. The port and starboard tanks deck fills directly over the tank tops. Check you might find a dip stick.

 

[syjos]

Purchasing a boat that doesn’t have gauges for the fuel tanks. Any advice as to keeping up with the amount of fuel in tanks ? Or is it worth it to install fuel Gauges??
Thanks for any insights!

If the fuel tank has a valved drain, create a sight gauge using a small diameter polyurethane clear tubing from the drain to the vent line. Utilize a "T" on the vent line and drain.

Add valves to the sight gauge tubing setup and leave them closed except when taking a reading.

 

[Swfla]

I'm going to guess that the previous owners were fine with no gauges. It depends on your personal preference, personality/awareness and how you intend to use the boat. Also the number of fuel tanks you have. All of the above mentioned methods work well. Personally, I'd find gauges a must have for water and waste tanks. Welcome and feel free to share as much info about the boat in your profile once you've closed the deal.

 

[Comodave]

What type of a boat is it? And what is the capacity of the fuel tanks? What are your cruising plans? All of these would factor into a decision as to whether or not gauges are needed. If it is a single engine full displacement trawler with large fuel tanks then gauges may not be needed since the fuel burn would be low and range long. If it is a planning hull with large twin engines and smaller tanks then gauges are necessary, IMO. Give us some more info to make recommendations on. Good luck on your purchase, hope it works out for you.

 

[Datenight]

Our first trawler, the Green boat, had dip sticks. After a season we had a very good idea of our usage. We later added a Flowscan and found it to be extremely accurate.

The second trawler was a North Pacific 39. We had fuel gauges and the Cummins engine management system which showed real time usage and total use. Very easy to keep track of fuel burn.

Our new North Pacific 45 (I know, post pictures) has the above and sight tubes. I guess we have moved up over the years however, the dip stick method worked well and would not be an issue for me buying a boat.

Rob

 

[koliver]

Only my dinghy has a fuel gauge. Only my dinghy gives me any anxiety when the gauge is showing less than 1/2 full. I don't actually know how much fuel the dinghy carries in the tetrahedral tank under the bow seat. Once I put 10 gallons in, usually I fill when it needs about 5, due to that anxiety.

In my diesel trawler, getting about 2 mpg, carrying ~600 gallons of fuel, taking 2 to 3 years to consume 600 gal, I have never had any concern about fuel. I usually fill up twice a year, once on the "big trip" and again in the fall, to leave the tanks full over the winter. I keep a log. In it, I record hours from fill to fill, and with a steady rate of consumption at ~2 mpg, a steady 8 knot speed, I always know when to ease up on the nozzle, as I near full.

Stay away from gauges for fuel, they cause anxiety.

 

[AlaskaProf]

I have electro-mechanical gauges, like most everyone here. Not worth your time and money to install them.

Fill your tanks, burn some (doesn't require more than a few hours) log your run times carefully, fill and calculate your burn. Thereafter use your clock to measure fuel levels. (This, of course, assumes you know the capacity of your tanks).

 

[FF]

Tank Tender

tanktender.com

The original precision tank measuring system. One instrument measures from 1 to 10 tanks. It gauges the liquid level in water, diesel & holding tanks.‎Installation & Operation · ‎Pricing / Order Form · ‎About · ‎Pressure Checking

 

[GaryPete]

I have sight gauges on my twin Perkins diesels and shortly after adding fuel, the level is pretty close to before. What did you mean by “leave them closed except when taking a reading”? I have no dipstick, 250 gallon tanks, and only a sight gauge that pretty much only tells me there is fuel in the system. Beyond “topping off” and monitoring from there, any other options with these sight gauges?

 

[Chris Leigh-Jones]

I have sight gauges on my twin Perkins diesels and shortly after adding fuel, the level is pretty close to before. What did you mean by “leave them closed except when taking a reading”? I have no dipstick, 250 gallon tanks, and only a sight gauge that pretty much only tells me there is fuel in the system. Beyond “topping off” and monitoring from there, any other options with these sight gauges?

I think I can help here. When I was at sea (a long time back) we had tank sight gauges, large ones on ocean going ships. The test valve was manually operated, normally shut. So if the glass were to break the only leak would be the fuel oil in the sight glass. Boiler gauges are sometimes the same, normally closed but opened to take the level. It's a failsafe design.

Hope this helps.
Chris

 

[GaryPete]

Thanks. I feel like the really novice that I am here! Reading all of the threads, a few mentioned in short, valves are closed, add fuel, open valves to allow leveling, then close valves to operate. I have never opened those valves, so now am I to assume the sight gauges are not giving me accurate readings? Makes sense I guess. But I can’t get my head around if they are both closed, it seems like a trapped level is in the sight gauge. So do you periodically open to reset the level? Gads, am I a novice!

 

[Portage_Bay]

I have sight gauges on my twin Perkins diesels and shortly after adding fuel, the level is pretty close to before. What did you mean by “leave them closed except when taking a reading”? I have no dipstick, 250 gallon tanks, and only a sight gauge that pretty much only tells me there is fuel in the system. Beyond “topping off” and monitoring from there, any other options with these sight gauges?

Regarding reading your fuel level. You've got a valve or valves closed somewhere. Or a blockage of some kind. If the sight gauges are open to the tank they will work.

 

[Portage_Bay]

Thanks. I feel like the really novice that I am here! Reading all of the threads, a few mentioned in short, valves are closed, add fuel, open valves to allow leveling, then close valves to operate. I have never opened those valves, so now am I to assume the sight gauges are not giving me accurate readings? Makes sense I guess. But I can’t get my head around if they are both closed, it seems like a trapped level is in the sight gauge. So do you periodically open to reset the level? Gads, am I a novice!

Yes, you open the valves to read the tank level. Then close the valves for safety. And yes, with valves closed the reading is inaccurate.

 

[Scottwb96]

I added Maretron Tank Level sensors to mine... Easy install and the data is transmitted to my MFDs. I also have a site gauge (I have an "odd" configuration, my tanks are all tied together, so only one site gauge)... While I was adding the sensors I also added them for the fresh water tanks... Nice to know where I am at a glance for everything...

 

[GaryPete]

If the fuel tank has a valved drain, create a sight gauge using a small diameter polyurethane clear tubing from the drain to the vent line. Utilize a "T" on the vent line and drain.

Add valves to the sight gauge tubing setup and leave them closed except when taking a reading.

My electrician also mentioned the Maretron sensors. We just put in the NMEA2K and WiFi this week to send navigation info (Navionics) to my iPad. Thinking of adding engine and fuel sensors as well.

 

[Scottwb96]

GaryPete,
the sensors are great. I also added the fuel flow sensors from Maretron as well. Good info, especially for longer trips and finding that optimum burn rate... All of which is DIY type stuff if you know your way around a tool box and basic 12v electrical...
I added the Wakespeed WS500 voltage regulator and finally got rid of the Balmar external regs... Way more control and EASY to program vs Balmar and that STUPID magnetic dot switch "thing" (I REALLY hated that thing!!!)

Next up is the SeaGauge G2 28 function sensor interface unit.... Converts all my old analog engine gauges/signalling to N2K readable info. Also puts the info on a MFD (or an Ipad)...

 

[AlanT]

Thanks. I feel like the really novice that I am here! Reading all of the threads, a few mentioned in short, valves are closed, add fuel, open valves to allow leveling, then close valves to operate. I have never opened those valves, so now am I to assume the sight gauges are not giving me accurate readings? Makes sense I guess. But I can’t get my head around if they are both closed, it seems like a trapped level is in the sight gauge. So do you periodically open to reset the level? Gads, am I a novice!

No worries! Experience is the only way to gain knowledge on such things. In a perfect world you would leave the valves at the top and bottom of the sight tube in the OPEN position all the time and then you would easily be able to see the amount of fuel in your tanks. By marking the sight tube with the prior reading such as marking on a strip of masking tape, you can also figure out roughly how much you are are consuming on a long run which is useful to know.

But we are not in a perfect world and the reason that everyone will tell you to close those valves whenever you are not actually checking the fuel level is because the open valves create the possibility of a fuel leak if the sight glass (if it is glass) breaks, or if there is some other fault or damage to the sight tube or its fittings.

So check as often as you can with the valves open, then close both top and bottom before leaving the engine room.

On my new-to-me boat the sight tubes were unrated plastic and they failed survey for that reason. I replaced with Tygon which is transparent and rated for Diesel fuel.

~A

https://www.amazon.com/Tygon-Genuin...ocphy=9033430&hvtargid=pla-581002227028&psc=1

 

[Chris Leigh-Jones]

No worries! Experience is the only way to gain knowledge on such things. In a perfect world you would leave the valves at the top and bottom of the sight tube in the OPEN position all the time and then you would easily be able to see the amount of fuel in your tanks. By marking the sight tube with the prior reading such as marking on a strip of masking tape, you can also figure out roughly how much you are are consuming on a long run which is useful to know.

But we are not in a perfect world and the reason that everyone will tell you to close those valves whenever you are not actually checking the fuel level is because the open valves create the possibility of a fuel leak if the sight glass (if it is glass) breaks, or if there is some other fault or damage to the sight tube or its fittings.

So check as often as you can with the valves open, then close both top and bottom before leaving the engine room.

On my new-to-me boat the sight tubes were unrated plastic and they failed survey for that reason. I replaced with Tygon which is transparent and rated for Diesel fuel.

~A

https://www.amazon.com/Tygon-Genuin...ocphy=9033430&hvtargid=pla-581002227028&psc=1

Top valve is usually left open as it connects to a the headspace in the tank. Bottom valve, spring loaded normally closed. Press it to see the fuel level. If it does not change check the top valve is open and connected to the tank. If still nothing then probably something is blocked and needs a looksee. Good luck.

 

[STB]

I have have saddle tanks and electrical gauges. I also have a dipstick left by the prior owner and a $99 brass oil dampened (in)clinimeter I bought for decor from a seller in India on eBay. I now see them only on Alibaba:
-- https://m.alibaba.com/product/60400075164/2016-High-Quality-Brass-Clinometer.html
-- https://m.alibaba.com/product/60400...HTB1qarILXXXXXaGXpXXq6xXFXXXg.jpg_220x220.jpg

Any time the tanks become significantly unbalances, the inclinometer is actually the 1st tell (at least at the dock). It is surprisingly accurate and consistent. This has happened for example, when I've run the generator for days during storm-related power outages or set my valves wrong.

The dipstick, constructed by a PO from a piece of mahogany with gallon measures notched with a knife and labelled with a sharpie, reportedly during a fill up, has been unending useful. Twice relatively new gauges or senders have failed. The stick? Simple and 100% reliable.

 

[GaryPete]

Thanks to everyone on this trail. You greatly expanded my knowledge on this fuel system. I will be on the boat tomorrow and report back my findings with the valves.

 

[Codger2]

.....and a $99 brass oil dampened (in)clinimeter ..........

Any time the tanks become significantly unbalances, the inclinometer is actually the 1st tell (at least at the dock). .

With Maretron fuel gauges you actually have a visual source of determining unbalance in your saddle tanks. (Other than standing on the dock and looking!) I added a tackle center that weighed about 400 lbs, causing a slight list to starboard. My Maretron fuel gauge pick up the list immediately.

 

[STB]

Hey Codger2,

My KUS USA reed switch senders have a discrete step every 21mm, so they are very accurate and the gauges seem to be pretty good, too.

But that silly (in)cinometer? Literally infinite resolution.

Also, it is always on, uses no power, etc.

Of course...it is a combined measurement of people, water tanks, holding tank, fuel tanks, boat attitude, etc.

 

[Dougcole]

I added Maretron Tank Level sensors to mine... Easy install and the data is transmitted to my MFDs. I also have a site gauge (I have an "odd" configuration, my tanks are all tied together, so only one site gauge)... While I was adding the sensors I also added them for the fresh water tanks... Nice to know where I am at a glance for everything...

Hey Scott,


Can you tell me a bit more about your maretron sensors/gauges? Both mechanical senders on my two tanks have stopped working, I consider mechanical senders to be all but useless. I'm looking at the TLM100. Looks like I can pull out the old sender on the top of my tank, put the TLM100 with a focus tube in it's place and use NEMA2000 to monitor it on my Garmin MFD. Am I missing something here?


Thanks,


Doug

 

[GoneDiving]

Yes, you open the valves to read the tank level. Then close the valves for safety. And yes, with valves closed the reading is inaccurate.

Without stating the obvious, the the amount the level drops when the valve is opened is the amount used since the last check. An easy way to determine usage per hour/nm etc.

Of course, if you have massive tanks and low daily burn this is easier said than done with any level of accuracy. A day's burn is a rounding error for me. ?

 

[GoneDiving]

The dipstick, constructed by a PO from a piece of mahogany with gallon measures notched with a knife and labelled with a sharpie, reportedly during a fill up, has been unending useful. Twice relatively new gauges or senders have failed. The stick? Simple and 100% reliable.

This is a good idea. I struggle to read permanently mounted fuel dip sticks on stationary, land based tanks. I can only imagine trying to get any sort of accurate reading from one that has been sloshing around on the ocean.

Sight tubes are simple and accurate. A sliding cable tie or oring can be used to measure usage over numerous readings. The hoses do yellow overtime so just carry $10 worth of spare hose or change as required.

 

[stubones99]

Top valve is usually left open as it connects to a the headspace in the tank. Bottom valve, spring loaded normally closed. Press it to see the fuel level. If it does not change check the top valve is open and connected to the tank. If still nothing then probably something is blocked and needs a looksee. Good luck.

The valves are not there for the sight tube breaking, but primarily for an engine room fire. ABYC also frowns on spring closed (dead man) valves, since fire can remove the tension from a spring. If a fire started, your open valves would feed the fire fuel for hours...

About the top valve being open??? If your boat sinks, that could leak out fuel into the water, exposing you and your insuror to a bigger cleanup bill. It helps contain the spill by having two valves, one at the top, one at the bottom, kept closed except when reading the sight tube.

 

[catalinajack]

Yeah, that Balmar reed switch is quite annoying. I considered going to the Wakespeed and getting rid of the Balmar regulators and Centerfielder but the regulators are adjusted to where they need to be and don't need to be touched again unless I change battery chemistry. That will not be a possibility for another four or five years. I will have sold the boat by then. Still, the Wakespeed is tempting.

GaryPete,
the sensors are great. I also added the fuel flow sensors from Maretron as well. Good info, especially for longer trips and finding that optimum burn rate... All of which is DIY type stuff if you know your way around a tool box and basic 12v electrical...
I added the Wakespeed WS500 voltage regulator and finally got rid of the Balmar external regs... Way more control and EASY to program vs Balmar and that STUPID magnetic dot switch "thing" (I REALLY hated that thing!!!)

Next up is the SeaGauge G2 28 function sensor interface unit.... Converts all my old analog engine gauges/signalling to N2K readable info. Also puts the info on a MFD (or an Ipad)...

 

[catalinajack]

I keep a two-foot carpenter's level on the lower helm. Close enough. Perfection is the enemy of good.

I have have saddle tanks and electrical gauges. I also have a dipstick left by the prior owner and a $99 brass oil dampened (in)clinimeter I bought for decor from a seller in India on eBay. I now see them only on Alibaba:
-- https://m.alibaba.com/product/60400075164/2016-High-Quality-Brass-Clinometer.html
-- https://m.alibaba.com/product/60400...HTB1qarILXXXXXaGXpXXq6xXFXXXg.jpg_220x220.jpg

Any time the tanks become significantly unbalances, the inclinometer is actually the 1st tell (at least at the dock). It is surprisingly accurate and consistent. This has happened for example, when I've run the generator for days during storm-related power outages or set my valves wrong.

The dipstick, constructed by a PO from a piece of mahogany with gallon measures notched with a knife and labelled with a sharpie, reportedly during a fill up, has been unending useful. Twice relatively new gauges or senders have failed. The stick? Simple and 100% reliable.