The Hemswell group

 

RAF Hemswell -No 97(SM) Squadron RAF
was the main site with four satellite stations

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

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

 

The topography of Lincolnshire and other areas where sites were to be constructed were flat which 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 Cathedrals used were Ely (Feltwell Group), York and Beverley both in Driffield Group

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 one well remembered occasion on  e of our surveyors who shall for the time being remain anonymous thought that he had attached the tripod to a rope in order to lower it to the ground threw said tripod over the edge for it to go crashing to the ground, thanks to the RAF workshops a repair was completed.

 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

http://jonathan.rawle.org/gallery

This was one of the elevated triangulation stations used
 


I cannot find any photographs of the period but thanks to the ORDNANCE SURVEY
I can display photographs of the top of Lincoln Cathedral.
 


Geodetic Tavistock on top of Lincoln Minster (Corporal Griffiths)

©Crown copyright Ordnance Survey. Published with thanks to and the permission of Ordnance Survey

 

Geodetic Tavistock on top of Lincoln Minster


 

©Crown copyright Ordnance Survey. Published with thanks to and the permission of Ordnance Survey

 

Geodetic Tavistock on top of Lincoln Minster showing the observers platform


 

©Crown copyright Ordnance Survey. Published with thanks to and the permission of Ordnance Survey

 


Bilby Towers

Bilby towers can be built o a height of 103 feet approximately 31.4 metres and are two independent towers, the inner tower is for the instrument and the outer to carry the observing party and their equipment

I cannot find any photographs but thanks to the ORDNANCE SURVEY

I can display photographs of  Bilby Towers under construction & completed

The Completed Tower is 103ft high, we never needed 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

©Crown copyright Ordnance Survey. Published with thanks to and the permission of Ordnance Survey

 

Bilby Tower construction, nearing completion

©Crown copyright Ordnance Survey. Published with thanks to and the permission of Ordnance Survey

 

Climbing the tower

©Crown copyright Ordnance Survey. Published with thanks to and the permission of Ordnance Survey

 

Looking up the completed tower

©Crown copyright Ordnance Survey. Published with thanks to and the permission of Ordnance Survey

 

A distant view of the completed tower

©Crown copyright Ordnance Survey. Published with thanks to and the permission of Ordnance Survey

 

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