The Hemswell group

 

The topography of Lincolnshire being flat necessitated the use of triangulation stations on elevated positions.

Lincoln Cathedral was one of those used. The climb was up a narrow spiral stone staircase which prevented the use of back packs, I forget the actual number of steps but am sure that it was in excess of 200. The theodolites , lamps and batteries had to be carried up in ones arms. I spent many hours on the top light keeping.
Details from OS  Lincoln - SK9771 - On the roof of the Central Tower, where the nave meets the transepts.

Other elevated trigs were on Church towers and water towers. Water towers required the surveyor to climb up a ladder usually under the tank, along a walkway and finally up a ladder on the outside of the tank. The tops were curved surfaces which required great care by the surveyor.

On the sites themselves it was often necessary to build a Bilby Tower which could be constructed to a maximum of 105 feet. These towers comprised two unconnected towers one inside the other. The inner tower was to carry the instruments and the outside one the observing party. When light keeping it was also necessary to carry the lead acid batteries to the top. We did try using long electrical cable but the voltage drop was too great to produce enough light at the lamp. Initial instruction on building these towers was given by a party from the Ordnance Survey at RAF Hemswell.

Lincoln cathedral

Reproduced with the kind permission of Jonathan Rawle.

Thanks to the ORDNANCE SURVEY, I have photographs of the top of Lincoln Cathedral & Bilby Towers.

To view the thumbnails below, click on the thumbnail, to return click back button in IE

Geodetic Tavistock on top of Lincoln Minster (Corporal Griffiths)

Geodetic Tavistock on top of Lincoln Minster click to enlarge

Crown copyright Ordnance Survey

Published with thanks to and the permission of Ordnance Survey

Geodetic Tavistock on top of Lincoln Minster

Lincoln Minster click to enlarge

Crown copyright Ordnance Survey

Published with thanks to and the permission of Ordnance Survey

Photographs of  Bilby Towers under construction & completed

The Completed Tower is 103ft high, we never need the full height and most were either 30ft or 60ft

We were trained in the construction of these towers by the Ordnance Survey

The 1st section of both the outer & inner towers completed over a pillar

The buried ends are fixed to railway sleepers

The First sections, click to enlarge

Crown copyright Ordnance Survey

Published with thanks to and the permission of Ordnance Survey

Bilby Tower construction, nearing completion

Nearing Completion click to enlarge

Crown copyright Ordnance Survey

Published with thanks to and the permission of Ordnance Survey

Climbing the tower

Climbing the tower click to enlarge

Crown copyright Ordnance Survey

Published with thanks to and the permission of Ordnance Survey

Looking up the completed tower

Looking up the completed tower click to enlarge

Crown copyright Ordnance Survey

Published with thanks to and the permission of Ordnance Survey

A distant view of the completed tower

Completed tower click to enlarge

Crown copyright Ordnance Survey

Published with thanks to and the permission of Ordnance Survey

 

RAF Hemswell -No 97(SM) Squadron RAF

 3 Thor IRBM launchers - Dec 1, 1959 - May 24, 1963.

Hemswell click to enlarge

RAF Ludford Magna -No 104(SM) Squadron RAF

3 Thor IRBM launchers-Jul 22, 1959 - May 24, 1963.

Ludford Magna click to enlarge

RAF Bardney -No 106(SM) Squadron RAF

3 Thor IRBM launchers - Jul 22, 1959 - May 24, 1963

Bardney click to enlarge

RAF Coleby Grange - No 142(SM) Squadron RAF

3 Thor IRBM launchers - Jul 22, 1959 - May 24,

Coleby Grange click to enlarge

RAF Caistor -No 269(SM) Squadron RAF

3 Thor IRBM launchers - Jul 22, 1959 - May 24, 1963

Caistor click to enlarge