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How do gages for wate, fuel and holding tank work?
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Jolly Roger
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December 8, 2010 - 6:50 pm
Member Since: March 27, 2010
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Could anyone please tell me how the water, fuel and holding tank gages are supposed to work on the DE 45 I recently bought? There is a fitting in the top of the tanks with a very thin plastic pipe coming out the center. The gages all have a central tube, which I suppose it for a similar pipe, but they have no pipe on them and I have yet to find where the other end of the tubes leads. How do these work, without any visible electrical connection on the gage? I hope someone can help, because I have no idea how much fuel or water I have, and how full the holding tank is.

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Erick
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December 9, 2010 - 2:31 pm
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It sounds to me like you have one of the Tank Tender systems like my Windsong has.  Does it look like this:

 

 

Here is the link to the company: http://www.thetanktender.com/  I need to rebuild mine, but I might go another route once I get to that point of the project (rebuilding the whole boat).

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Scott Carle
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December 9, 2010 - 5:16 pm
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Could you post some pictures? Nothing on my boat based on your
description sound familar. I have a fuel guage only and it is a float
type electrical sender that goes to an automotive type gauge in the
footwell instrament panel. Neither my water tanks or the holding tank that we removed had gauges.

scott

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Scott Carle DE38 Cutter s/v Valkyr
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Jolly Roger
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December 9, 2010 - 6:30 pm
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Hi Erick,

I don't appear to have a master guage like you show, I have separate gauges, two water, two fuel and a holding tank guage, non of which are connected to anything, but the have a thin pipe out the back which looks to me like it should have a pipe plugged into it. But if it's a Tank Tender type system, what powers the gages?

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Jolly Roger
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December 15, 2010 - 11:03 pm
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I have managed to solve my own inquiry:

As I stated, the water tanks and holding tank simply had a 1/8” neoprene pipe sticking out the top which was not connected to anything. There are three separate gauges, two water and one waste, all having a single stem out the back the same ID of the neoprene pipe. But when we connected a gauges to a tank pipe nothing happened.

Then I started to think logically and blew down the pipe to the gauge and bingo! it went round to full. We then sank the end of the pipe in a bucket of water, and the gauge also registered.

So it appears the tanks have a vertical pipe to the bottom and as the liquid level rises and falls it causes a pressure variation in the pipe, which makes the gauge move. In order to get them operational we will have to empty the tanks, then re-fill them and I bet the gauges register.

The top tank connection is marked “tank” but it is not the Tank Tender product, because it uses separate gauges, and they were not in business when the boat was made. I’m sure someone has seen it or heard about it, but it is new to me. It is so dead simple and foolproof I don’t know why it is not used on all boats—no electrical connections, no sending units, no nothing!

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Eolian
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January 6, 2011 - 1:07 pm
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The water and waste gauges on the DE45 are simply very sensitive pressure gauges.  The tube fitting on the back of the gauge is connected thru a (probably rotted) piece of thin plastic tubing to a dip tube in the tank in question.  As the fluid level in the tank rises, the air in the dip tube, tubing, and the gauge internals is compressed, and the gauge is calibrated to show this as fluid level.

 

They don't work very well.  For this to work, the system must be absolutely leak free.  Any leaks will allow the air trapped in the dip tube, tubing and gauge to escape, equalizing the pressure.  I replaced the tubing on mine, and for a short while was able to make the gauges display properly, but eventual leakage took its toll.  If you would like help with calibration procedures, let me know

 

The fuel gauge is electrical - just like the one in your car.  In fact, I changed out the senders on Eolian because one of them had rusted off and was AWOL (probably in the bottom of the tank).  I got standard senders from NAPA, and they are working fine.

 

bob

s/v Eolian

DE45 #11

Seattle

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Scratch
Nova Scotia, Canada
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January 6, 2011 - 7:07 pm
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I don't have any sending units on any of my water tanks.  This is a bit of a pain, I'd like to know what's in there.  The fuel on the other hand is a little more "classical".  The previous owner rewired and re plumbed the entire boat.  He really did a jam up job but not everything is 100% done.  He installed a sending unit in the fuel tank but never installed a gauge.  Instead there is a small dipstick that has it's own purpose built holder with it's own dedicated spanner for the plug in the tank.  I will eventually hook up the sender but I can't say it's at the top of my list of things to do...the dipstick has yet to lie to me.

 

What are the preferred sending units for the water tanks?  I feel those are more important to me right now.

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