Water Meter

[Issywa]

I'm thinking about installing a water meter in my supply line in lieu of tank monitors as I think this will be my simplest and most cost effective option to let me know how much water is remaining in my tanks.

I'd install it just downstream of the valve that allows me to switch tanks. By resetting the meter to zero after each filling (or recording the reading), and also after switching tanks, I'll know how much water I have remaining.

The meter would be located under a settee with easy access for both installation and reading.

Anybody have experience with this setup? Am I missing anything in my quest for simplicity?

[Chotu]

Originally Posted by Issywa

I'm thinking about installing a water meter in my supply line in lieu of tank monitors as I think this will be my simplest and most cost effective option to let me know how much water is remaining in my tanks.

I'd install it just downstream of the valve that allows me to switch tanks. By resetting the meter to zero after each filling (or recording the reading), and also after switching tanks, I'll know how much water I have remaining.

The meter would be located under a settee with easy access for both installation and reading.

Anybody have experience with this setup? Am I missing anything in my quest for simplicity?

Only one comment and it’s about simplicity.

I’m not sure if you are installing new tanks or if your tanks are poly (translucent), but if they are, the most simple way is to make it such that you can see a bit of the tank. Easy to just see where the waterline in the tank is.

If it’s a built in, non-seethrough tank, another bit of simplicity is to drill holes into the tank and install 90 degree plumbing elbows. One elbow up high on the tank facing downward, the other near the bottom of the tank facing upward. Connect the elbows with a straight piece of see through hose.

Now fill your tank with known quantities of water, stopping along the way several times to note the level of the liquid in the tank/hose. Mark how many gallons you have put in at each interval and write it right on the tank.

It becomes a useful sight glass.

If you don’t care about exact water amounts and just want to know if your water is half gone or almost full, don’t label anything and just look at the sight glass



A good part of simplicity is not creating chores for yourself (constantly dealing with resetting a water meter) and always coming up with the solution that won’t break

[tkeithlu]

Chuto is absolutely right that a sight glass is the way to go. I use them on both freshwater and diesel tanks, and mark known quantities with a sharpy. If you don't want to build your own, you can buy them here:

https://www.mcmaster.com/liquid-level-indicators

At the simplist, a 90 degree elbow coming out of the tank, with a clear plastic hose treaching from there to back in the top of the tank does the job.

If you can't get down beside the tank to see the water level, there ar two possibilities:

One, use a shop mirror on a stick to view it. Two, rig a float in the tank with a wire coming up through a guide wire in the top. The higher the wire, the higher the water level in the tank. Municipal water tanks use something similar.

[tkeithlu]

Here's another approach, a tank float gauge:

https://www.mcmaster.com/float-gauges

In all of the options that Chuto and I have recommended, you are not dependent on electricity, and you are measuring the actual amount of water in the tank, not how much you have used. A flow gauge could be rather badly wrong for measuring tank contents if the tank leaks or a downstream leak is too slow to cause the flow impeller to notice.

[SailingMed]

Originally Posted by Issywa

I'm thinking about installing a water meter in my supply line in lieu of tank monitors as I think this will be my simplest and most cost effective option to let me know how much water is remaining in my tanks.

I'd install it just downstream of the valve that allows me to switch tanks. By resetting the meter to zero after each filling (or recording the reading), and also after switching tanks, I'll know how much water I have remaining.

The meter would be located under a settee with easy access for both installation and reading.

Anybody have experience with this setup? Am I missing anything in my quest for simplicity?

I had a water flow meter in my previous boat for many years and it worked perfectly and very accurate. It was battery operated and the batteries seemed to last for ever. Extremely simple to instal. I had it connected just before the water pump.

[tkeithlu]

OK. You're talking about a totalizer. Let me get the nomenclature right in my head. Sailing med has had good experience therewith, and they are simple to install in a water hose. If you go that route, it's expensive for a resetable totalizer - $220 or so from McMaster-Carr. But a non-resetable meter is cheap. But then, how much energy are you going to put into this in your logbook? Having to check the previous reading and subtract it from the current reading? How about glancing at the sight gauge and thinking, hmm, better fill up soon?

https://www.mcmaster.com/water-totalizers

[Dockhead]

Originally Posted by tkeithlu

Chuto is absolutely right that a sight glass is the way to go. I use them on both freshwater and diesel tanks, and mark known quantities with a sharpy. . .

Sight glasses are wonderful -- simple and effective. HOWEVER, on a boat, they have one big drawback -- it's a weak point and if something gets thrown against one of those in rough weather, you can lose the contents of the tank.


For that reason, I wouldn't have a sight gauge on a boat. Next best thing however is one of those mechanical gauges someone linked to above -- IF the top of the tank is reasonably visible.



I personally use standard WEMA gauges for fuel and water. I've had to replace the water one, but the fuel one is still going strong. I have an ultrasonic Maretron N2K one for black water, and wouldn't mind changing my water gauge to that type (or leaving the WEMA one).



I think a liter-counting water meter is a great idea; something I've thought about myself. Gigantic advantage of this over any other method is that it works when the boat is heeling. I was in a long distance race last summer and a big problem was not knowing how we were doing with water consumption. We had 5 people on board and 1000 liters which should have been plenty for the roughly 8 day event, but as it turns out we somehow were using more than we expected the first few days, and didn't know about it until several days later because the boat was constantly on a heel and we couldn't get a reading from the gauge.

[Chotu]

Dock head: that’s why my post suggests using a pair of 90 degree elbows and clear hose, such as vinyl or pex or whatever. Not a glass one.

[Dockhead]

Originally Posted by Chotu

Dock head: that’s why my post suggests using a pair of 90 degree elbows and clear tubing, such as vinyl or pex or whatever. Not a glass one.

Everyone will have his own evaluation of the risk -- YMMV.


But those elbows and such can all be ripped off by flying junk in bad weather. Maybe not a big risk on a catamaran like yours -- hence YMMV.


Another YMMV is tank mounting -- many of us have tanks which you can't get to in any convenient way to read a sight glass.

[tkeithlu]

"Sight glasses are wonderful -- simple and effective. HOWEVER, on a boat, they have one big drawback -- it's a weak point and if something gets thrown against one of those in rough weather, you can lose the contents of the tank."

Dockhead, good point. That's why my sight"glasses" are vinyl hose with ball valves at the bottom fixture. That even "saves" the previous reading.

[Copacabana]

Originally Posted by Dockhead

Sight glasses are wonderful -- simple and effective. HOWEVER, on a boat, they have one big drawback -- it's a weak point and if something gets thrown against one of those in rough weather, you can lose the contents of the tank.

I agree. Why add complexity and points of failure, especially for something as important as water?

If your water and diesel tanks have easy access from the top, a simple marked wooden dowel dipstick is simple and accurate. I monitor my diesel tank that way. I haven't gotten around to making a dipstick for my 500 liter keel water tank, but I keep a mental calculation of water use going and I'm getting pretty good at "guestimating" how much water I have.

I wonder if a simple automotive fuel gauge could be rigged up for water.

[chris95040]

Originally Posted by tkeithlu

...That even "saves" the previous reading.

Clever!

[sv_pelagia]

We also have sight glasses (actually, not glass) on our diesel and water tanks and all with valves at bottom. Easy peasy (tho' a bit of a pain while fueling up... one person down below monitoring sight tubes).

Our water tanks' sight tubes are open at the top... we open the valve and see how far the water goes. If full, it comes out the top of the tube end and puts a little fresh water into bilge. We then shut off the valve. In practice, we only use the water tank sight tubes to see how much water is remaining in a tank.

The only tank we have electronic monitors is our holding tank: we have two types of monitors on thexone tank. One or other not always reliable. Pain in the ass. But sight tube here neither practical (location of tank hard to see; clogging a concern) nor pleasant idea (not something I want to look at).

[Issywa]

Appreciate the comments - informative and timely. Covid must be creating a lot of free time....

The location of my tanks precludes the use of sight glasses but I like the concept. And I think I'm too lazy to install monitors and snake wiring through a circuitous route. So a meter it will be.

[Mike OReilly]

I installed a flow meter on the main line so I can measure exactly how much water gets used. I've used it for two season and it has worked flawlessly. It's easily read, run on a small battery, and is reset with every fill.

I considered a sight gauge, or even some of float gauge. In the end, the flow meter was the easiest, least intrusive, and safest option that did the job. But I think the other solutions would work as well.

In addition, I use a flow meter on the fill hose so I know how much water is going into the tank.