Day Tank Fill Switch

[Mike GB32]

Hello
I'm in the process of installing a day tank in the fuel system on my Grand Banks 32. I would like to have a level switch to fill the tank automatically. I've been looking at multi level reed switches with a manual override. Seems like the way to go but a little pricey so I thought I'd pose the question- Has anyone done this and had a good outcome with a different switching approach?

 

[Comodave]

I don’t think that I would put an auto fill on a fuel tank. If it messes up you could pump fuel overboard. The fines are very steep and your insurance does not cover fines.

 

[rslifkin]

I don’t think that I would put an auto fill on a fuel tank. If it messes up you could pump fuel overboard. The fines are very steep and your insurance does not cover fines.

For the most part, I agree. But for a day tank, I'd just place it so that an overflow line can be run back to the source tank. Then, worst case, the day tank gets overfilled and the fuel just spills back to the tank it came out of rather than going overboard.

 

[Mike GB32]

I agree about overfilling.
My plan is to have an overflow tube and valve to whichever tank Im filling from.
Lower than the vent.

edit- you beat me to it rslifkin

 

[PM]

I guess I am ignorant,(at least I admit it).

What is a "day tank" and why would anyone want one on a 32 foot boat?

pete

 

[rslifkin]

I guess I am ignorant,(at least I admit it).

What is a "day tank" and why would anyone want one on a 32 foot boat?

pete

It's a small, separate fuel tank. The idea is that fuel gets transferred from the main tank(s) to the day tank, often with a filter inline. Then it gets burned from the day tank.

Serves 2 purposes. First, if you filter it during transfer, there's less risk of bad fuel causing filter clogging and engine shutdown issues (as it would clog the transfer filters which can be changed without a loss of engine use). Second, it avoids the issue of sucking air in rough seas when the main tanks get low.

 

[PM]

Thanks. Guess I still can't see the need on a 32 foot boat.

I carry 350 gallons of fuel on my Albin. I NEVER run low on fuel! How could I when I burn only a few gallons an hour. At fifty or so miles a day I am looking at a 90 day supply.

Two Raycor 900s and two secondary engine filters keep my fuel clean, plus I am careful about where I buy fuel.

Why bother with a day tank when, IMHO the space below decks could be much better put to use than a jury rigged extra fuel tank.

Just one mans opinion, but I guess that is sorta why you brought it up.

pete

 

[Mike GB32]

"a jury rigged extra fuel tank"??
Thats a bit harsh.
Yeah, I'm sure the concept of a day tank could be debated right there next to the anchor debate. I was hoping to avoid that debate by the way I worded my original question.
I was hoping for some input regarding the question of how to switch the fuel pump.
Nevertheless, thanks for your input.

 

[twistedtree]

My last boat had a timer switch, like in old hotel bathrooms for the IR heat lamp. You turn the knob to 10 min, and it pumps for that amount of time and stops. My pump moved fuel at a very constant rate, so I just figured out how many gallons could be transferred for every 10 minutes, and wrote a new scale on the timer. Based on my tank gauge I knew approximately how much fuel needed to be transferred, and I'd dial in that many minutes/gallons. It was simple, worked well, and limited things that could break.


For the boat we are building I have considered something more automated, but haven't done anything further. For the reasons people have brought up, I think a number of fail safes would be needed. I was thinking of reading the tank level from the maretron level sensor, then control the pump from a PLC. I figured good cross checks would be to make sure the tank level is increasing as expected anytime you think the pump is on. Also that the level stops moving when the pump is off. And I figured on only filling to maybe 80% so if the level didn't stop rising as expected, you could sound an alarm before an overflow occurred.


I think it would be a fun project, but it's pretty hard to argue that it's really a time saver or a safety enhancement. In fact it probably decreases safety. And there is another complication which is selecting which tank to draw the transfer fuel from. So you now use motorized valves, and watch for level movement in both tanks?


So I'm going to install another timer to start with, and will probably never do more.

 

[psneeld]

I agree, a well done day tank is far from a jury rigged extra tank. It serves several purposes that are valuable.... but most likely overkill for the average recreational boat.


I would probably do one if a great location was available.


I would not go auto fill... easy enough for the timer or just plain manual fill. Buy an wind up kitchen timer...I use it for all kinds of reminders.

 

[Mike GB32]

I do like the “keep it simple” approach.
I might use a timer if the price of the system keeps going up.

 

[High Wire]

A timer switch would be a simple fix. 25 gallon Day tank would be good for at least 10 hours cruising time.

 

[FF]

A built in rotary hand pump as used to empty 55g drums would be a fast easy way to fill the day tank.

Plumb the return back to the fuel supply , no worries about overfilling.

A refrigeration site valve could show when its full.

Every day after the noon sight , simply crank till the site glass shows full, you are set for the day.

A gravity day tank would mean no air locks ever in the fuel system. Great!


https://www.globalindustrial.com/p/...MIz_O7ssih6AIVooVaBR0DGgnMEAYYAyABEgKvlPD_BwE

 

[Portage_Bay]

I wouldn't automate day tank filling. Even with a proper overflow return to main tank set up. I've twice seen people somehow manage to mess that up resulting in large fuel spills with clean up expenses and fines.


I would consider something like the Murphy switch gauge L150 / EL150. You can wire it to set off an alarm when the level gets low.

 

[catalinajack]

Thanks. Guess I still can't see the need on a 32 foot boat.

I carry 350 gallons of fuel on my Albin. I NEVER run low on fuel! How could I when I burn only a few gallons an hour. At fifty or so miles a day I am looking at a 90 day supply.

Two Raycor 900s and two secondary engine filters keep my fuel clean, plus I am careful about where I buy fuel.

Why bother with a day tank when, IMHO the space below decks could be much better put to use than a jury rigged extra fuel tank.

Just one mans opinion, but I guess that is sorta why you brought it up.

pete

Pete, I share your opinion. From reading this forum for many years, my sense is that many boaters worry far too much about the highly unlikely. Many, if not most, boats use Racor filter heads. We have all read about adding a vacuum gauge to any brand of filter head to indicate a soon-to-be plugged filter. The idea that a day tank is essential to dangerous, inopportune full stops while crusing just doesn't make sense to me. If that happens, it means a boater has not paid attention. If, in the highly unlikely case that a dirty load of fuel is purchased, the filters will NOT immdeiately become plugged up. They may more quickly do so but the vacuum gauges will tell the boater when this is happening long before engine stoppage. I suppose there may be that one-in-a-million case but I doubt even that. So, no paranoia - apologies to anyone who is miffed by the use of this word - for me, no expensive fuel polishing system, no daily transfers of fuel to a day tank. I will simply monitor the vacuum gauges and change filters when, and only when, they are approaching the end of their useful life.

 

[PM]

Amen catalinnajack! Why take the extra step of putting fuel through the same filter you use to filter it prior to its introduction to the engine.

Come on, a 32 foot boat?

pete

 

[jleonard]

In MY opinion a day tank is a much better option than constantly running a "fuel polishing" system.
That said I'll stick to my multi-stage filtering system that has served me so well for the past 15 years.

 

[catalinajack]

A fuel polishing system certainly hurts nothing but, in my opinion, does virtually nothing versus simple sequential filtering and changing filters when a vacuum gauge says it is time.

In MY opinion a day tank is a much better option than constantly running a "fuel polishing" system.
That said I'll stick to my multi-stage filtering system that has served me so well for the past 15 years.

 

[hollywood8118]

I had a 100gal. day tank on Volunteer, it had been installed by the previous owner builder. As he was a rocket engineer ( literally ) and a frugal tinkerer it was comprised of a mix of old surplus aviation parts. It was a vertical tank that the first 75 gal. would gravity feed. The transfer pump was big 25 gal per minute B-24 aux. pump. It was controlled by some type of air diaphragm switch that shut the pump off at exactly the same fuel level every time. I really liked the way the system worked and it transferred all the fuel I used for my 9 year tenure of ownership. I had the fail safe of a manifolded overflow that went back to the tank the fuel came from.


You could use a switch like one on this page to shut down the transfer pump through a relay. Not a air switch but a possibility.



https://cdn.shopify.com/s/files/1/0221/4946/files/Std-vt-ss.pdf?1093


HOLLYWOOD

 

[Jmarsh203]

Day tank automation

As a tankerman who would loose his license and livelihood with a spill from negligence this would be the only setup I would consider other than monitoring it in person with a hand switch. This is a day rank setup for our generators on board the tow boat I’m on. You have two Murphy switches (white ones) setup on alarms, one for high level before it overfills and the other a low level in case the system does not kick on when it’s supposed to to fill it up so you don’t run the generators dry. Then there are two float switches (Red ones) one high one low for kicking on and off the transfer pump.

 

[Jmarsh203]

And considering a day tank is supposed to be exactly that, which is enough fuel to run a day or two I don’t really see the point in automating it, doing proper engine room checks what’s a couple extra min every day in the engine room flicking a switch and watching fuel go up in a sight glass. A proper professional setup like above is probably close to $800 just for those 4 float switches and I just don’t see the advantage over doing it by hand. I’d rather spend the money somewhere else

 

[Mike GB32]

As a tankerman who would loose his license and livelihood with a spill from negligence this would be the only setup I would consider other than monitoring it in person with a hand switch. This is a day rank setup for our generators on board the tow boat I’m on. You have two Murphy switches (white ones) setup on alarms, one for high level before it overfills and the other a low level in case the system does not kick on when it’s supposed to to fill it up so you don’t run the generators dry. Then there are two float switches (Red ones) one high one low for kicking on and off the transfer pump.

Now we’re talking! Thanks for posting this. It’s interesting to see a professional solution.

 

[FF]

Instead of a system vacuum gauge a more accurate filter monitoring setup would be a DP gauge.

A differential pressure gauge (can be a Murphy alarmed unit) is installed at the helm where it can be watched.

It mounts to the input and output of the filter and registers the difference.

 

[timb]

Instead of a system vacuum gauge a more accurate filter monitoring setup would be a DP gauge.

A differential pressure gauge (can be a Murphy alarmed unit) is installed at the helm where it can be watched.

It mounts to the input and output of the filter and registers the difference.

i disagree well kinda .while a DP gauge would be more accurate in filter checking,but a plain vacuum gauge would alert you to any restriction in the system before the gauge .

i like the idea of having a day tank . but not of buying and installing one .maybe if my to do list was empty but that will never happen .

 

[djones44]

I have a day tank for my Dickinson diesel stove. It is tricky, trusting my air pressure gauges. The key for me is keeping an eye and an ear on the overflow vent for warning burps, battens in hand, and remembering not to overfill it, using the hand pump, beyond the indicated 8".

 

[Brooksie]

The reed/float switches are quite inexpensive at McMaster or Grainger. I would use two in series for safety.

That said, reed switches won't carry much amperage so your pump needs to be small or relay controlled.
While solving one perceived problem, you may be creating another if this fill system goes down for some reason.

 

[Vinny]

I would never have an auto fill on the day tank.

Filling the day tank as needed puts you down in the engine room to give a quick look over while there.

My main reason why not is that things simply fail when you don’t want them to.

You could put all your fuel overboard from the vent and never know till you figure out your day tank is empty, or the Coast Guard happens to call.

I would do the opposite and put a Murphy float switch on the tank to kick off the pump, and sound alarm if at a high level (95%) when I got side tracked on something while topping up the day tank.

 

[BrianSmith]

+1 on the twist-type timer switch. Works great for me. (I also set a time on my phone to check it a few minutes early, just in case!)

 

[Xsbank]

I don’t understand the purpose of a day tank in a simple boat but why not just gravity feed it? My GB32 had a pair of Racors, switchable with a remote vacuum gauge, which fed to a second Racor with a small electric pump for filter changing. Manufactured fuel lines. No leaks no spills and more than adequate filtration.

 

[MYTraveler]

My "day" tank gravity feeds (from its top, T'd to a valved outlet at its bottom) to the mains. There is no risk of overfilling from transferring fuel.