Need to measure some cylindrical storage tanks for their diameter

[Howard]

What's the easiest way to do this? Most of them are between 8 and 14 feet in diameter.

 

[MotF Bane]

Duct tape and a piece of string. Tape one end of the string to the tank, walk around the tank, wrap a bit of tape as a marker to the loose end to indicate where the tape begins to overlap. Measure this length of string.

 

[Gibson486]

measuring tape?

 

[rcpratt]

Measure circumference and use maths?

 

[highland145]

Measure circumference and use maths?

Which one?

 

[highland145]

What's the easiest way to do this? Most of them are between 8 and 14 feet in diameter.

linear algebra.

 

[Imp]

Which one?

The ones with the pies and the diameters.

 

[highland145]

The ones with the pies and the diameters.

pecan?

 

[Turin39789]

pecan?

3.14

 

[highland145]

3.14

Who the hell ate the other .86?

 

[BoomerD]

pecan?

Pecan pie ALWAYS gives the wrong answer. Only apple pie is accurate enough for measurements.

Everyone knows this.

Use a 100 foot tape measure...divide by 3.14...get answer that's close enough for government work.

 

[highland145]

Pecan pie ALWAYS gives the wrong answer. Only apple pie is accurate enough for measurements.

I must disagree. Pecan pie w/vanilla ice cream. The right answer.

 

[gorcorps]

As said... easiest way is use string to get circumference and then use math magic to make it go *poof*

THE CIRCUMFERENCE IS NOW DIAMOND... er... DIAMETER

 

[JTsyo]

Lay a ruler next to it, get above the cylinders and take a picture, then use the ruler as the scale.

 

[Howard]

Lay a ruler next to it, get above the cylinders and take a picture, then use the ruler as the scale.

barrel distortion

I was hoping that you guys could come up with something other than walking around with a string. The tanks are damn dirty and I can't get access to the full circumference for many of these tanks.

 

[Daedalus685]

Stand x meters away from the tank (distant to closest point of the tank, not its centre as if you could measure that well... you know), measure the angle (theta) subtended by the edges of the tank.

Provided x is large enough (at least double the radius to get a close value):

D=2xtan(theta)/(1-tan(theta))

 

[ussfletcher]

Well, you could measure your distance away from the tank and take an angular separation measurement of both edges...

Edit: I lose.

 

[dank69]

Sub it out to someone in India

 

[Analog]

Fill them full of water - take note of how many gallons. Once you've figured out the volume of water, a quick calculation will give you the diameter of the tank.

 

[rcpratt]

Fill them full of water - take note of how many gallons. Once you've figured out the volume of water, a quick calculation will give you the diameter of the tank.

Clearly this is simpler than a string and circumference.

 

[Analog]

Clearly this is simpler than a string and circumference.

actually, I was thinking that the cylinder could be accelerated to near the speed of light, and its mass variation coupled with time dilation would yield a relativistic approach to this problem, but alas, I couldn't find the right approach. Perhaps there is something in QED..

 

[highland145]

barrel distortion

I was hoping that you guys could come up with something other than walking around with a string. The tanks are damn dirty and I can't get access to the full circumference for many of these tanks.

No access to the top?

 

[SlitheryDee]

Enter nine 9s, take the square root, and press the integer key.

 

[Gibson486]

barrel distortion

I was hoping that you guys could come up with something other than walking around with a string. The tanks are damn dirty and I can't get access to the full circumference for many of these tanks.

find as builts?

 

[DisgruntledVirus]

Ask the owner of said tanks?

Look at the purchase order for said tanks?