Before the laser level

[Figment]

We've mentioned the use of a water level in passing a few times around here, but we've never really gone into the process in any detail. Here we go....


25' of clear vinyl tubing, and a bucket of water, colored with food coloring, or as in this case, with raspberry jell-o because the grocery store was having a deal. $10.37, batteries included.


To get the fluid into the tubing, you get the tubing into the fluid. Anyone who's ever siphon-cleaned an aquarium knows the deal. Feed the tubing into the water a bit at a time, keeping the one end below the surface the whole time. Hold it down with a rock or something.


Cool little tip: 1/4" tubing is the perfect size because it can be plugged with an ordinary pencil. Plug one end of the tubing to prevent the fluid from running out when removed from the bucket.


So the concept is dead simple. With the ends of the tubing unplugged, the water in each end will always and forever be level. Tape one end to each side of the boat.


And futz with the boatstands until things line up....


Presto! level boat.
Oh, but it's best to level it fore-and-aft before leveling side-to-side. As many times as I've done this, I always seem to forget that little gem.

[Tim]

It's hard to beat the simplicity and accuracy of the good ole water level.

Getting the water into the tubing can sometimes be a trick, but once you have it, you're golden (or should I say green...thanks to the food coloring). I had fun with this myself. But the thing is extremely accurate and easy to use.

Building and using a water level

[Eric]

It's hard to beat the simplicity and accuracy of the good ole water level.... But the thing is extremely accurate and easy to use.

I feel the need to stir this colorful soup a bit--just 'cause I'm sitting at work and this is much more appealing at the moment...

My attempts to use this method have not been very satisfactory. I attempted to level the form for the slab of my shop using about 75' of garden hose with a couple of 4-5' pieces of clear tubing connected to each end. After filling the tube with water and dragging it around the site to check the corners, I found that my results were inconsistent. It was as if the surface tension of the hose was enough to hold the water higher in one end.

I double checked to make sure that I didn't have a big air bubble or any constriction in the rig. Each time I brought the ends together to compare them, the level in the two clear sections would differ by a significant amount. I didn't spend a lot of time fooling with it as I had access to an optical level and simply jumped to that alternative, but it has stuck with me that this method can be sensitive to technique (as all tech can, I guess).

Looking at the pictures above, in many of them it appears that the water level is perpendicular with the walls of the tubing instead of parallel with the ground. This would seem to make an accurate determination of level somewhat difficult.

-- Eric

[dasein668]

I've seen that color before: on Heather's face as we passed Sequin! That's why I get to express the boat up to Penobscot Bay without her now!

[grampianman]

Faith an' Begorrah,
Fellahs,
It's Tim O'Lackey!

The Leprechaun has landed. Now if only we can find his pot o' gold.


Cheers,
Ian

[Tim]

It's hard to beat the simplicity and accuracy of the good ole water level.... But the thing is extremely accurate and easy to use.

I feel the need to stir this colorful soup a bit--just 'cause I'm sitting at work and this is much more appealing at the moment...

My attempts to use this method have not been very satisfactory. I attempted to level the form for the slab of my shop using about 75' of garden hose with a couple of 4-5' pieces of clear tubing connected to each end. After filling the tube with water and dragging it around the site to check the corners, I found that my results were inconsistent. It was as if the surface tension of the hose was enough to hold the water higher in one end.

I double checked to make sure that I didn't have a big air bubble or any constriction in the rig. Each time I brought the ends together to compare them, the level in the two clear sections would differ by a significant amount. I didn't spend a lot of time fooling with it as I had access to an optical level and simply jumped to that alternative, but it has stuck with me that this method can be sensitive to technique (as all tech can, I guess).

Looking at the pictures above, in many of them it appears that the water level is perpendicular with the walls of the tubing instead of parallel with the ground. This would seem to make an accurate determination of level somewhat difficult.

-- Eric

There needs to be a valve (or other opening) on the ends of the hose to allow the water level to equalize inside, and even a small air bubble can drastically affect the results. Getting all the air out is one of the more challenging parts of creating this device, and I think a full length of clear hose makes this easier. I fought the air problem for much of a day in order to get mine to work; if I hadn't been so stubbornly determined to make it work at the time, I would have gone out and bought a good laser level instead and saved myself a lot of time!

And of course one has to learn to deal with the miniscous of the water at each end. For tiny fractions of an inch, the water level isn't able to be read accurately enough, of course, but when leveling a hull this sort of accuracy is unnecessary and impractical anyway.

I didn't find "angled" water inside the tube to be a problem, FWIW.

[Eric]

There needs to be a valve (or other opening) on the ends of the hose to allow the water level to equalize inside, and even a small air bubble can drastically affect the results. Getting all the air out is one of the more challenging parts of creating this device, and I think a full length of clear hose makes this easier.

I think air in the line is the probable cause of my difficulty, though I filled the hose under pressure from a sillcock before adding the open ended clear tubing to the ends with standard crimp on hose fittings. I did have to add a bit to get the water to show in the clear ends and there was some other thrashing around (a cold spring rainy day, as I recall).

Thanks for the reply! I also prefer simple machines...

-- E

[Figment]

I also think that the ratio of head to run has a lot to do with the effectiveness of a water level.

For example, when leveling the boat side to side, with most of the tubing lying on the ground and two nearly-vertical ends rising 66" or so, the level was quick to respond to minute changes.
When leveling fore-and-aft, my 25' length of tubing wasn't touching the ground at all, but was slung under the hull in its catenary of only about 30" depth, the level was markedly slower to respond.

Leveling a slab, with only 4" of head to move water through 75' of hose, I'll bet the fluid was VERY slow to respond.

[Dan H]

I bought these becasue they have the valves and caps on top of the tubes. First time I used them, the tube popped off the valve. They leaked where the tube fits on the valve. I slipped some Orings on the valve and jambed the tubes on with all my might. They work great now.

[Sailordave]

[quote="Eric
much more appealing at the moment...

My attempts to use this method have not been very satisfactory. I attempted to level the form for the slab of my shop using about 75' of garden hose with a couple of 4-5' pieces of clear tubing connected to each end. After filling the tube with water and dragging it around the site to check the corners, I found that my results were inconsistent. It was as if the surface tension of the hose was enough to hold the water higher in one end.


-- Eric[/quote]

Having used a water level MANY years ago to install ceilings before we had a laser.... Small diameter hose is okay for projects that you don't have a lot of hose.... But for anything over 10 feet say... you really need a larger diameter hose to get accurate results. .5 inch 5/8" is better.

Not sure whether it has to do w/ the surface tension or b/c the tiniest air bubbles are that much harder to dislodge but hose dia DOES affect your accuracy.

BTDT.

[Figment]

I was just at Big Orange and happened to spot this little doohickey out of the corner of my eye.



An electronic/water level by Zircon with a pressure sensor that beeps when you're level.
I dunno that I'd pay $35 for it, but that would make singlehanded use a lot more convenient.

What WILL they think of next?

[Capn_Tom]

I used one when setting the concrete forms for the pad my boat sits on. IMHO the tube is too small making air bubble an issue. But then I was working at ground level.

[Quetzalsailor]

The centrifugal force due to the earths' rotation slings the water higher at the more southerly end. Means that you would have to have the boat aligned north-south to level side to side. It's worth about 27 miles of extra diameter at the equator. And of course, if you were slow in your observations, there would be a tidal effect in the water in the hose.

As for getting enough head to move the water on the floor slab job, you could raise the ends, and the waterline, by some known offset. Tie the hose to tall stakes at each end and measure down to the proposed slab elevation.

[Tim]

The centrifugal force due to the earths' rotation slings the water higher at the more southerly end. Means that you would have to have the boat aligned north-south to level side to side. It's worth about 27 miles of extra diameter at the equator. And of course, if you were slow in your observations, there would be a tidal effect in the water in the hose.

Would you calculate what this amounts to for the typical user trying to level a small boat?

I'm guessing it's not measurable for any practical purpose, and is therefore not really particularly germane, though no one is denying that the earth bulges at the equator.

[Figment]

Funny! I think you have it backward, though.

The relative difference between the ends of the hose would be greater near the poles, not at the equator.

Centripetal acceleration is velocity squared divided by radius. Apply a mass and you have what is commonly known as "centrifugal force". The mass isn't a variable, though, so let's stick with V2/R.

At the poles, near the "ends" of the sphere, the relative difference in radius (and therefore, velocity as well) is greater than at the equator, where large distances between ends of the hose have little effect on the relative radius, or distance from the axis of rotation.

Really, though, one should always orient the boat north-south when on the hard so that the sun doesn't fade one side faster than the other.

[Ancient Race]

Really, though, one should always orient the boat north-south when on the hard so that the sun doesn't fade one side faster than the other.

So it's wrong to just do it for an even tan?

[Quetzalsailor]

It is, of course, a very quiet Friday morning.

Tides on the Great Lakes are said (by the Canadian Hydrological folks) to be from 1 to 4 CM, usually well obscured by wind and atmospheric effects. The tide in a short hose would be indeed hard to measure.

I'm'a not so sure Figment has his correction right. Water levels in a north-south hose would be skewed the same as the earth is: higher at the equator. And the reason is that the objects on the surface, farther from the axis of rotation, are moving faster. Without bothering too much with the elliptical geometry, the distance along the surface from pole to equator is 6214.75 miles, and the difference between the elevation at pole and at equator is 13.24 miles. The slope would vary according to where you were on the meridian, but the average is 1:469.39199, or so.

I'm'a quite sure Figment has his correction right! He speaks of 'relative' height. Clearly you get farther from the axis faster when you are closer to the pole.

[Capn_Tom]

Good Lord I think I logged into the wrong bulletin board.