RE: [PSUBS-MAILIST] bubble pressure (Papenberger)

["Jens Laland" <laland@artematrix.org>]

Jay

The Papenberg Tiefenmesser und Restauftriebsmesser (Depth Gauge and
Rest-Buoyancy Meter) 'belongs' to your category #1, the capillary gage.

To use the word 'capillary' when talking about the Papenberger can be a
bit misleading since the inner diameter of the (plexi)glass tubing used is
often between 7 and 10 mm.

I would therefore assume that this type of gauge would not be more subject
to error from clogging of the inlet than a Bourdon tube gage.

However, I agree that the Papenberger should only to be used at very
shallow depths, normally down to 15 - 20 m (if going deeper the valve to
sea is closed). Having said that, I still think it would be quite useful
in a psub even down to around 80 ft (24 m).

Please note that my previous mail to David is quoted below for your
information.

regards,
jens

** David
**
** "The so-called Papenberg depth gauge is used by the German Navy for
** precision reading at periscope depth. Ref.:
**
http://lab.artematrix.org/submarine/images/project/papenberg_and_trim_principles.jpg
** The measurement is based on the compression of an air cushion, and so the
** reading in the cylindrical glass tube is not linear. The residual buoyancy
** of the boat associated with its floating position is plotted on this
** instrument in addition to the depth scale (starting with the surfaced
** flotation line and decreasing to zero when the top of the superstructure
** has been reached). Moreover, the contour of the cross section of the boat
** is plotted in association with the depth scale (distorted). The water
** level of the instrument is illuminated horizontally, and minute tendencies
** for attitude changes can be identified from the curvature of the meniscus
** before the water level in the tube rises or falls."
**
http://lab.artematrix.org/submarine/images/project/papenberg_trim_sketch.jpg
** (from the book: 'Submarine Design' by Ulrich Gabler)
**
** Here is a photo from inside an old norwegian (but german built) Kobben
** class submarine, ref.:
** http://lab.artematrix.org/submarine/images/project/IMG_0224.jpg
**
** and here one from U 995 (type VII C) in Kiel (Laboe), ref:
** http://lab.artematrix.org/submarine/images/project/IMG_0209.jpg
**
** If you decide to make one then let me know as I have made a little program
** that calculates the offsets needed to space out the scale correctly, i.e.
** according to how you physically size your own gauge (ID of glass tubing,
** length of scale, start air volume, etc). I also have a few sketches on how
** to make the various parts, and how to assemble, plus some ideas on how to
** test and calibrate the final thing when installed in your boat.
**
** regards,
** Jens





************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003.  Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.

If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
	removeme-personal_submersibles@psubs.org

Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of
our server receiving your request.

PSUBS.ORG
PO Box 53
Weare, NH  03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************