UR101 Stay Behind Cave (Operation Tracer)
Posted on January 21, 2016 / 1572
Zone : Upper Rock
poi type : Tunnel Entrance
Location :
Condition : Fair

Thanks to Wikipedia  for the main part of this.

Note that the plot arrow on the map is not at the precise location.

Operation Tracer was a covert cave location dug out in Gibraltar, so that in the event of its capture, the people inside could monitor the harbour and feed information back to the British Command.  Similar cave are believed to have been considered for Malta, Aden and particular Tincomalee in Sri Lanka (Ceylon).  The latter was the last British Port in the Far East after the fall of Hong Kong and Singapore.

In the summer of 1941, Rear Admiral John Henry Godfrey (1888–1971), the Director of the Naval Intelligence Division of the British Admiralty, decided to establish at Gibraltar a covert observation post which would remain operational even if Gibraltar fell into enemy hands. The scheme was sufficiently top secret that none of the Operation Tracer meetings took place at Whitehall. Rather, they were held at Godfrey’s residence at 36 Curzon Street, Mayfair, Central London.

From this observation post in Gibraltar, soldiers sealed inside the cave could monitor the movement of enemy vessels and report back by radio to the Admiralty. British officers, including Commander Geoffrey Birley and chief engineer Colonel Fordham, performed reconnaissance of the Rock of Gibraltar and selected the existing tunnel system for Lord Airey’s Shelter as the site of Operation Tracer. Initially, plans were made to provide a year’s worth of accommodations for five men, including food, water, sanitation, and wireless communication. The scheme was later changed to one which would support six men. Eventually, provisions for seven years were supplied. The Director of Naval Intelligence (DNI) consulted with several experts on the feasibility and requirements of the scheme.

By late December 1941, construction of the complex had commenced. The tunnelling work was performed in secret and the labourers were unaware of the exact site. All those involved in the construction of the Operation Tracer facility were immediately returned to England when it was completed, out of concern that they might leak the plan.

The room which would provide the living quarters for the men was 57,600 cubic feet (1,630 m3), with dimensions of 45 ft x 16 ft x 8 ft (14 m x 4.8 m x 2.4 m), at an elevation of 1,350 feet (410 m) The two observation apertures, one west over the Bay of Gibraltar, and the other east over the Mediterranean, provided ventilation. Each opening was initially planned to be 12 inches x 6 inches (30 cm x 15 cm). The opening on the East side was large enough for one person to lie in the sun and thus overcome the problem of living in a cave for a long period of time.   In addition, there was a 10,000 imperial gallons (45,000 l) water tank. Toilets were adjacent to a small radio room that contained the equipment for the wireless communications, which included a Mark 3 transmitter and HRO Receiver. Three 12 volt, 120 ampere batteries would be charged with either one of two generators, one bicycle-propelled and the other hand-cranked. The bicycle, which also drove a ventilation system, had its chain replaced with a leather strap, in order to minimise the noise when it was in use. In addition, an outside aerial was recommended. A rod aerial measuring 18 feet (5.5 m) in length would be inserted through the east observation aperture.

 

A staircase near the main chamber, at the level of the radio room and toilet facility, led up to the east observation post. It was decided that the aerial would be hidden by withdrawing it into a pipe after use, with the pipe extending down the stairs which led to the main room. While it had initially been planned that the observation apertures would both be slits, the final choice was for the eastern aperture over the Mediterranean to be larger, overlooking a narrow ledge, yet still completely concealed. The opening and ledge were sufficiently large that a man could climb out onto the platform for fresh air. Part way up the main set of stairs was another set which led to the west observation post. The western slit over the bay was concealed with a concrete wedge. The entirety of the main chamber had been plastered and its floor covered in cork tiles, both methods to reduce sound transmission. The entrance passage had loose soil, to facilitate burials if needed. It also had loose bricks to further brick up the tunnel access once the six men had been sealed inside the cave.

 

At a January 1942 meeting, a report by two of the consultants was analysed. The report made suggestions as to personnel, exercise, provisions, including food, alcohol and tobacco, ventilation, and sanitation. If one of the team members died, it was recommended that their remains be embalmed and cemented. Those at the meeting decided that the Operation Tracer team should have six members: an officer who would serve as leader of the team, two doctors, and three telegraphists. It was proposed that a rehearsal be conducted to evaluate the psychological suitability of the proposed team members. It was suggested that the rehearsal take place in Scotland. At a meeting held the following month, in February 1942, it was recommended that Lieutenant White of the Royal Naval Volunteer Reserve be interviewed. It was proposed that once the Tracer team was chosen, a second team be organised, and observations posts at other places such as Aden and Malta be considered.

UR101 Stay Behind Cave (Operation Tracer)
Thanks to Wikipedia  for the main part of this.

Note that the plot arrow on the map is not at the precise location.

Operation Tracer was a covert cave location dug out in Gibraltar, so that in the event of its capture, the people inside could monitor the harbour and feed information back to the British Command.  Similar cave are believed to have been considered for Malta, Aden and particular Tincomalee in Sri Lanka (Ceylon).  The latter was the last British Port in the Far East after the fall of Hong Kong and Singapore.

In the summer of 1941, Rear Admiral John Henry Godfrey (1888–1971), the Director of the Naval Intelligence Division of the British Admiralty, decided to establish at Gibraltar a covert observation post which would remain operational even if Gibraltar fell into enemy hands. The scheme was sufficiently top secret that none of the Operation Tracer meetings took place at Whitehall. Rather, they were held at Godfrey’s residence at 36 Curzon Street, Mayfair, Central London.

From this observation post in Gibraltar, soldiers sealed inside the cave could monitor the movement of enemy vessels and report back by radio to the Admiralty. British officers, including Commander Geoffrey Birley and chief engineer Colonel Fordham, performed reconnaissance of the Rock of Gibraltar and selected the existing tunnel system for Lord Airey’s Shelter as the site of Operation Tracer. Initially, plans were made to provide a year’s worth of accommodations for five men, including food, water, sanitation, and wireless communication. The scheme was later changed to one which would support six men. Eventually, provisions for seven years were supplied. The Director of Naval Intelligence (DNI) consulted with several experts on the feasibility and requirements of the scheme.

By late December 1941, construction of the complex had commenced. The tunnelling work was performed in secret and the labourers were unaware of the exact site. All those involved in the construction of the Operation Tracer facility were immediately returned to England when it was completed, out of concern that they might leak the plan.

The room which would provide the living quarters for the men was 57,600 cubic feet (1,630 m3), with dimensions of 45 ft x 16 ft x 8 ft (14 m x 4.8 m x 2.4 m), at an elevation of 1,350 feet (410 m) The two observation apertures, one west over the Bay of Gibraltar, and the other east over the Mediterranean, provided ventilation. Each opening was initially planned to be 12 inches x 6 inches (30 cm x 15 cm). The opening on the East side was large enough for one person to lie in the sun and thus overcome the problem of living in a cave for a long period of time.   In addition, there was a 10,000 imperial gallons (45,000 l) water tank. Toilets were adjacent to a small radio room that contained the equipment for the wireless communications, which included a Mark 3 transmitter and HRO Receiver. Three 12 volt, 120 ampere batteries would be charged with either one of two generators, one bicycle-propelled and the other hand-cranked. The bicycle, which also drove a ventilation system, had its chain replaced with a leather strap, in order to minimise the noise when it was in use. In addition, an outside aerial was recommended. A rod aerial measuring 18 feet (5.5 m) in length would be inserted through the east observation aperture.

 

A staircase near the main chamber, at the level of the radio room and toilet facility, led up to the east observation post. It was decided that the aerial would be hidden by withdrawing it into a pipe after use, with the pipe extending down the stairs which led to the main room. While it had initially been planned that the observation apertures would both be slits, the final choice was for the eastern aperture over the Mediterranean to be larger, overlooking a narrow ledge, yet still completely concealed. The opening and ledge were sufficiently large that a man could climb out onto the platform for fresh air. Part way up the main set of stairs was another set which led to the west observation post. The western slit over the bay was concealed with a concrete wedge. The entirety of the main chamber had been plastered and its floor covered in cork tiles, both methods to reduce sound transmission. The entrance passage had loose soil, to facilitate burials if needed. It also had loose bricks to further brick up the tunnel access once the six men had been sealed inside the cave.

 

At a January 1942 meeting, a report by two of the consultants was analysed. The report made suggestions as to personnel, exercise, provisions, including food, alcohol and tobacco, ventilation, and sanitation. If one of the team members died, it was recommended that their remains be embalmed and cemented. Those at the meeting decided that the Operation Tracer team should have six members: an officer who would serve as leader of the team, two doctors, and three telegraphists. It was proposed that a rehearsal be conducted to evaluate the psychological suitability of the proposed team members. It was suggested that the rehearsal take place in Scotland. At a meeting held the following month, in February 1942, it was recommended that Lieutenant White of the Royal Naval Volunteer Reserve be interviewed. It was proposed that once the Tracer team was chosen, a second team be organised, and observations posts at other places such as Aden and Malta be considered.

UR101 Stay Behind Cave (Operation Tracer)
Zone : Upper Rock
poi type : Tunnel Entrance
Location :
Condition : Fair
Conditions
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John C
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