Coastal Artillery question please, what is

[museumtom]

Hi guys and gals. I am just back from a weekend show in a coastal artillery fort. There is a feature just unearthed and they don’t know what it is or what it is for or how it is used. I know, I just know you guys will. All we know is it is called a Depression Range Finding Pedestal.

Thanking you all profusely for any help you can give to identify this, etc.

Kind regards.

Tom.

Here are some images of it;

[ianjonesncl]

Tom

This is a Depression Range Finder from the Heugh Battery in Hartlepool.

Looking at the Handbook of Artillery Instruments 1914 I believe the triangle is the location of a tripod stand. The Depression Range Finder would measure the angle from it's location to the target. From memory by knowing the height of the rangefinder, and the angle, the tangent can be worked out which would give the range.

Ian

[michaeldr]

Pages 451> here may be useful http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1904PA.....12..450P&db_key=AST&page_ind=1&plate_select=NO&data_type=GIF&type=SCREEN_GIF&classic=YES

[museumtom]

Thank you Ian, lots of information there but can you tell me what the little track that lead to the triangle is for please?

Kind regards.

Tom.

[ianjonesncl]

This is the principle:

[ianjonesncl]

Thank you Ian, lots of information there but can you tell me what the little track that lead to the triangle is for please?

Kind regards.

Tom.

Tom

I was wondering what it is for.....could it be as mundane as drainage !

[museumtom]

Its could very well be Ian, except it goes into the wall and down a flight of steps, roudn a corner and then stops. its a puzzle.

Thanks you for all your help.

Kind regards.

Tom

[centurion]

I have a feeling that some such devices contained electric comtacts that picked up motion as the equipment tracked the target and this was relayed by cable to a chart/map based plotting device from whence bearings, range and depression could be transmitted to the guns. So it could be a cable track.

[museumtom]

Centurian, you could very well be right Thanks for your help.

Kind regards.

Tom.

[Bombadier]

"Some instrument which would discover the varying range of the target as it steamed through the water was absolutely necessary. The solution of this problem was entirely due to the inventive genius of Capt. H. S. Watkin R.A. who, whilst stationed at Gibraltar during the 'seventies (1870s) produced the Depression Range Finder and the Position Finder. Both of these instruments made their appearance during the 'eighties. The D.R.F., when laid on the bow-waterline of the target, recorded the range of the target as it moved through the sea, the P.F. both the range and bearing. The discovery and development of electricity enabled this vital information to be transmitted direct to the guns by the means of dials so that, in the case of the D.R.F. with the line-layer laying direct on his target, the gun was given the correct elevation, and in the case of the P.F. the correct line and elevation without the layer seeing the target at all. These instruments were gradually installed in the coast-defences at home and abroad during the 'nineties and the early years of the twentieth century, the P.F.s to serve the heavy guns (9.2") and the D.R.Fs the medium ones (6")."

From "The History of Coast Artillery in the British Army" by Col K.W. Maurice-Jones, D.S.O. late R.A.

Published by the Royal Artillery Institution 1959

Hope this adds something

Nigel

[centurion]

The discovery and development of electricity enabled this vital information to be transmitted direct to the guns by the means of dials

So very likely a cable track

[museumtom]

Thank you all. Your help is very much appreciated.

Kind regards.

Tom.