Holding tank level indicator

[Bob Loewenstein]

So I was thinking: would a stud finder work to measure the level in my holding tank (fiberglass under the engine). I'm not anywhere near my boat so I can't check it out, but I did do some experiments with some containers at home and it sure looks like it might work. Has anyone tried this on their tanks?

[Larry DeMers]

Good idea! heh..could tape three el-cheapo stud finders to the tank, and then remotely turn them on? They would need to be calibrated of course, so that would not work too well.

I have been playing with a bubbler system (similar to the Tank Tender approach, but a lot less expensive). By using a single gauge that reads say 0-30in. of water, a set of small air control valves from an aquarium, used to select which tank you want to read, a 12vdc air pump (saved from an old air infuser for a bass boats live well..~$25 new), and some 1/8 in. nylon tubing (surplus), it is possible to read the exact level of liquid in all tanks that are fitted with a bubbler tube. The idea is that the air pump will send a small trickle of air under pressure to the tank where it will be bubbling out the end of the bubbler tube.
The more liquid in the tank, the more backpressure you have on the air being supplied for bubbling. Back pressure is reflected in the gauge reading of course, and when it is calibrated for the various tank sizes (in other words, top and bottom are claibrated on each tank, as are 1/4 full, 1/2 full,3/4 full), the actual backpressure can then be translated to depth of the tank. This works in all liquids, and is one of the main ways depth readings were taken in water towers, holding tanks and sewage facilities until recently, when they switched to an ultrasonic depth gauging system.
This idea has definite possibilities for our boats, but I don't have the time right now to fool with it further. Maybe after our lunch hits, we will find more time somewhere..under a log?
If anyone is interested, I can provide a diagram of the system, and sources for parts that I have obtained so far.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30

So I was thinking: would a stud finder work to measure the level in my holding tank (fiberglass under the engine). I'm not anywhere near my boat so I can't check it out, but I did do some experiments with some containers at home and it sure looks like it might work. Has anyone tried this on their tanks?

demers@sgi.com

[Ken Coit]

Check out "Swamp sounder: simple (not too elegant) gauge for your holding tank (Quick and Easy)" by Jerry Powlas in the most recent Mar/Apr issue of Good Old Boat. Exactly the same principles.

I like the idea of using an electronic stud finder; I think I will borrow my son's, try some experiments at home on a trash can and then try it next time I see Parfait.

For those who want to know more about electronic stud finders, try the link below rather than all the other thoughts that seem to leap to mind.

What a great resource this board is!


Ken
CD/36 Parfait
Raleigh, NC

Good idea! heh..could tape three el-cheapo stud finders to the tank, and then remotely turn them on? They would need to be calibrated of course, so that would not work too well.

I have been playing with a bubbler system (similar to the Tank Tender approach, but a lot less expensive). By using a single gauge that reads say 0-30in. of water, a set of small air control valves from an aquarium, used to select which tank you want to read, a 12vdc air pump (saved from an old air infuser for a bass boats live well..~$25 new), and some 1/8 in. nylon tubing (surplus), it is possible to read the exact level of liquid in all tanks that are fitted with a bubbler tube. The idea is that the air pump will send a small trickle of air under pressure to the tank where it will be bubbling out the end of the bubbler tube.
The more liquid in the tank, the more backpressure you have on the air being supplied for bubbling. Back pressure is reflected in the gauge reading of course, and when it is calibrated for the various tank sizes (in other words, top and bottom are claibrated on each tank, as are 1/4 full, 1/2 full,3/4 full), the actual backpressure can then be translated to depth of the tank. This works in all liquids, and is one of the main ways depth readings were taken in water towers, holding tanks and sewage facilities until recently, when they switched to an ultrasonic depth gauging system.
This idea has definite possibilities for our boats, but I don't have the time right now to fool with it further. Maybe after our lunch hits, we will find more time somewhere..under a log?
If anyone is interested, I can provide a diagram of the system, and sources for parts that I have obtained so far.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30

So I was thinking: would a stud finder work to measure the level in my holding tank (fiberglass under the engine). I'm not anywhere near my boat so I can't check it out, but I did do some experiments with some containers at home and it sure looks like it might work. Has anyone tried this on their tanks?

PPPPparfait@nc.rr.com

[Capt. Carol]

Why not remove the cover plate from the holding tank and look in? Kind of a simple solution, don't you think?



tbrhin1@gibralter.net

[Larry DeMers]

Well,umm, straight forward, yes. Simple? No. On my CD30, the holding tank is under the vberth. That means taking the bedding off the bed, moving the two large pads aside, and lifting the cover to the access port, then opening the holding tank and getting a great whif or two while you hurriedly peer in there with with a flashlight. Sounds like fun?
So that's why the interest in a remotely reading gauge..with the ability to also look in each water tank and the diesel tank, all with the same gauge. Makes life a little easier, gets current info to you quickly, and prevents several rather semi-serious accidents from happening (running out of fuel at the wrong time..overfilling the holding tank..water running out would be a problem for most folks (we can drink the water we sail in as long as we are off shore).

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 Lake Superior

Why not remove the cover plate from the holding tank and look in? Kind of a simple solution, don't you think?

demers@sgi.com

[Walt Bilofsky]

There are a number of commercial indicators around that use paste-on sensors that go on the outside of waste and water tanks. I have one on my CD 30 powerboat to monitor holding and water tanks. One of the most useful gadgets on my boat. Some are made for marine use. I think mine's an RV unit but it's worked OK for years.

See the link below for a number of models from one manufacturer.

- Walt



bilofsky@toolworks.com

[Dennis Ward]

So I was thinking: would a stud finder work to measure the level in my holding tank (fiberglass under the engine). I'm not anywhere near my boat so I can't check it out, but I did do some experiments with some containers at home and it sure looks like it might work. Has anyone tried this on their tanks?

I tried a cheep studfinder ($10) on the holding tank on my CD33, It did not work. Maybe a more expensive unit would.



dward34@aristotle.net

[John R.]

I never tried a stud funder but may fool around with it just to see what it can do. I don't know how you would adapt it to practical use if it did work. I think it would be more trouble then it is worth to adapt it. There are simpler solutions.

I have made "full indicators" out of a couple metal studs that are mounted in the inspection port cap. Supply 12v to a switch and then to a indicator light and run a ground lead to one stud and the other stud to the indicator light, When the fluid reaches the stud tips it completes the ground circuit and illuminates the light indicating it is time to pump out.

Design the stud length so it gives you plenty of warning before the level is completely to the top of the tank. Mine is set at about 4" from the top.

A very simple little design.

For the rest of the tanks I have a TankTender unit on the water tanks and fuel tank and it is extremely dependable and absolutely no maintenance.

So I was thinking: would a stud finder work to measure the level in my holding tank (fiberglass under the engine). I'm not anywhere near my boat so I can't check it out, but I did do some experiments with some containers at home and it sure looks like it might work. Has anyone tried this on their tanks?

I tried a cheep studfinder ($10) on the holding tank on my CD33, It did not work. Maybe a more expensive unit would.

[Richard Feffer]

You can actually drink the water you sail in??? That's scary! Much of the water we sail in comes out of somebody's holding tank!!! Municipalities, commercial traffic, pleasure craft and run-off. The further east in LI Sound you go, the cleaner the water gets, though.

For those with easy access to the holding tank cleanout (cover), try replacing the opaque cover with a clear one. Available at BoatUS or West. A flashlight will easily reveal the level of the contents.



RichFef@Prodigy.net

[Larry DeMers]

Understand that the water on Superior is so pure that we can do this while out off shore. The water there is in the 500 ft. deep category, with the deepest being at 1330 ft. It rarely goes above 45 deg. on the open lake (water temp), and we do wear winter parkas while crossing in August. Fascinating place. I would reserve this pleasure for emergencies myself, but it is certainly ok to do it, especially from below the surface water. Superior is the headwaters for the Great Lakes, as all water flows out from here thru the system, so water in Lake Michigan onwards should be considered unfit for drinking unless boiled.

Larry DeMers

You can actually drink the water you sail in??? That's scary! Much of the water we sail in comes out of somebody's holding tank!!! Municipalities, commercial traffic, pleasure craft and run-off. The further east in LI Sound you go, the cleaner the water gets, though.

For those with easy access to the holding tank cleanout (cover), try replacing the opaque cover with a clear one. Available at BoatUS or West. A flashlight will easily reveal the level of the contents.

demers@sgi.com

[Joe Mac Phee]

Gentlemen,

What in the world do you guys put in your holding tank that you would expect to locate with a STUD finder?? (OUCH)!!

At home trying to get warm, hoping that my holding tank is empty,

Joe Mac Phee
S/V Iolanthe
CD-30/K
Bristol RI

So I was thinking: would a stud finder work to measure the level in my holding tank (fiberglass under the engine). I'm not anywhere near my boat so I can't check it out, but I did do some experiments with some containers at home and it sure looks like it might work. Has anyone tried this on their tanks?

jvmacphee@aol.com

[Paul Hierstein]

Gentlemen,

What in the world do you guys put in your holding tank that you would expect to locate with a STUD finder?? (OUCH)!!

At home trying to get warm, hoping that my holding tank is empty,

Joe Mac Phee
S/V Iolanthe
CD-30/K
Bristol RI

So I was thinking: would a stud finder work to measure the level in my holding tank (fiberglass under the engine). I'm not anywhere near my boat so I can't check it out, but I did do some experiments with some containers at home and it sure looks like it might work. Has anyone tried this on their tanks?

Joe,
I'm sure it has something to do with the iron supplements they are taking!

Paul
Abre Alas
CD30C
Galveston, Texas



paulhstn@aol.com