Early Capillary Gauges

[Tusker]

Possibly a bit of a longshot here, but does anyone know if there are reproductions or have an idea on how to fashion a capillary gauge in the style worn in the early 1950s? I'd like to include one in my project but don't fancy the expense or rarity of an original.



Something like the 140 ft Soundor worn by this Scripps diver in 1948 is what I'm after.

Jacob

[SeaRat]

I’ll see if I can find something in my references and catalogs. It should be pretty easy to recreate.

John

[vance]

I have several of the newer kind (1960s?). You can have one for postage.

[SeaRat]

Well, believe it or not, the capillary depth gauga is now being hand-made to determine the maximum diving depth of diving animals. In this paper, the authors discuss and detail the way that they made these capillary depth gauges. This technique could be modified to make your own capillary depth gauge in the manner of the very old ones pictured above.

Capillary Depth Gauges for Diving Animals: An Assessment of their Accuracy and Applicability
Alan E. Burger and Rory P. Wilson
Bamfield Marien Station
Bamfield, British Columbia VOR 1BO, Canada


Abstract.--Gaugesto measurethe maximum depthsattainedby diving animalswere con-
structedfromplastictubinglinedwith solubleindicatorpowder,atacostof$0.10each.In
our tests,the differencesbetweenreal and estimateddepthsaveraged<3% with single
immersionsof gaugesto any depth up to 140 m. With multiple immersionserrors were
usually<10% andalways<25%. The accuracyofthegaugeswasnotaffectedbydepthor
duration of dive, rate of descent,or underwater movementssimulating a bird's swimming.
Errors resultedfrom severejarring of the devicesunderwater,plunge-diving,accumulation
of moisture within the tubes, and use of excessivehydrophilic indicator. Potential errors
associatedwith high air-sea temperaturegradientswere not realized in our tests.With
careful constructionand deploymentthe gaugesshould provide accuratedepth estimates
without adverselyaffectingfree-livinganimals.Methodsfor attachingthe gaugesto birds are reviewed.

...
Depth gauges were made from lengthsof flexible plasticTygon (R) tubing,coated internallywith a thin layerof icing sugar.The indicator was appliedby blowing gently through the open tubing to moisten the lumen walls and then sucking very small amounts of dry icing sugar up the tube. The tube was knotted tightly at one end, without stretching it, and cut to size. Except where noted,the tubing had an internal diameter of 1.6 mm and the lumen length was either 100 or 145 mm. Sample gauges were lowered into seawater at Bamfield, British Columbia. The lengthof undissolve idndicator (Ld) was read to the nearest 0.5 mm using a ruler, without stretchingthe tubing..."
sora.unm.edu/sites/default/files/journals/jfo/v059n04/p0345-p0354.pdf

John

[nikeajax]

Jacob, get some small tubing, closed at one end with a plug: you should be able to get some fuel-line at a hobby shop. Take a stiff plastic card and cut an "I" shape into it with a razor blade: push the folds back to nest the tubing in. Next time you go down, stop at the intervals you wish to denominate and mark it off with a pencil. When you go back up, fill in the numbers with something more permanent: anyway, that's one way.

JB

[SeaRat]

Here is another consideration, and that is the accuracy of the capillary depth gauge at altitude. I have a table from way back that shows the capillary depth gauge will be reading deeper than the actual depth, so a lot of us used this style depth gauge in the early 1970s when diving at altitude.

Altitude Corrections001 by John Ratliff, on Flickr

Here's a scientific paper that confirms this table.

pubmed.ncbi.nlm.nih.gov/10897866/

John

[SeaRat]

Two days ago I had a thought as I looked at my analog thermometer outside my garage window. That thermometer, with its center-mounted analog thermometer, looks a lot like those old depth gauges. My thought: you can purchase one of those thermometers in a white plastic rectangle, and spray paint out the lettering for the thermometer. Then string a long, looping bit of tubing around the edges, and you can make the lettering for depth beside the loop of tubing. It would be much like the originals.

Just a thought…

John

[surflung]

Here's a pretty straight forward construction method with pictures...
Capillary Depth Gauge w/Pictures

[herman]

I use to rebuild a lot of the round ones....and have a number of them. Been a while but pretty sure I have some tubing if you want it, or I'm sure I have a round gauge if you want one.

[vance]

Feb 5, 2024 15:33:31 GMT -8 herman said:

I use to rebuild a lot of the round ones....and have a number of them. Been a while but pretty sure I have some tubing if you want it, or I'm sure I have a round gauge if you want one.

Me, too. I have rebuilt several round ones. It should be pretty easy to replicate one of the old rectangular types.

[SeaRat]

Feb 5, 2024 8:06:51 GMT -8 surflung said:

Here's a pretty straight forward construction method with pictures...
Capillary Depth Gauge w/Pictures

Surflung,

That’s a great article. I found a photo of a U.S. Divers Company depth gauge which had a capillary depth gauge surrounding the Bourdon Tube gauge.

IMG_0274 by John Ratliff, on Flickr

John