The real reason is because you don't want them migrating up the water column while you're taking a reading, especially if they're big because it will change the water level for a bit.Why are bubbles a problem?
The water will level itself out if there are bubbles or not. In a water level, just compare the top surface of the water at each end of the tube?
If you were a real wine snob you'd reverse the process...drink the wine and fill the tube with the byproduct.Now that I'm thinking, if I use the wine, will be still called water line or will become wine line? Maybe I'm thinking too much about it already. Just need to go and get it done.
I was reading this description several times, but still don’t have a clear picture of how this supposed to work with only one end. Looks to me that you really need to move your bucket up and down for different measurements. If you doing that then you are essentially using to ends anyway. But I will try to understand it some more when I get home. Maybe I will need glass of wine with it to understandI use a slightly different method. I only use one end of the tube for all my measurements. Take your clear tube and submerge many coils of it into a 5 gal bucket
of water treated with a quart of rubbing alchohol and a bottle of food coloring from grocery store. When you submerge the tubing go slow and eliminate all bubbles in the hose. Then take just one end of the tube out and walk as far as needed to measure
your target. What you will get at the end of the tube you are holding is a constant
level indication and you can mark that on your target or multiple targets. When done for the day just coil the tube back into the bucket and put the top on the bucket.
What I sometimes do is tape the end of the tube to one end of a yardstick. and then tape the rest of the tube to the length of the yardstick so you can use the measurements
on the yardstick for comparison to other measurements when holding the yardstick vertical. The name for this contraption is "The Egyptian Magician"
Now I understand. Thank you. For the rest of the day I will be scratching my head about benefits of doing it this way versus 2 identical tube ends for 2 wing tips. Sorry for being slow, but I will get there eventually.Get a kitchen stool and place it in front of your plane. Put the bucket on the stool and
fill it up. Insert tube coil and remove air. Take one end of tube to end of wings or anything you want to measure anywhere on the plane that is higher than the water level in the bucket. Optionally use the yard stick at end of tube as mentioned. Adjust bucket level height as needed. ie take it off the stool. For instance measureing both wing tips could result in a reading of 31 inches if using the yardstick. Measure from the water line in the tube to the number on the yardstick etc.