Shelter Construction in Malta 1935-1942
On the 24th of June 1939 a bomb went off in Għallis in the North of Malta. It damaged two buildings nearby but the blast was largely deflected by two stone ‘screen’ walls, each one two and a half feet thick. They were damaged but retained their structural integrity. It was decided that this was how Malta would defend itself against the looming threat of high explosive bombs.
The Governor had ordered testing on the suitability of Maltese buildings to withstand bomb blasts. This was part of ongoing testing to determine the effects of bombs on local masonry going as far back as 1935 (FCO 141 8390). In this particular instance in 1939, the Public Works Department was ordered to find suitable land and buildings for the test. With cooperation from several services, a specific area close to the Għallis tower was selected and evacuated. The Navy wanted to test the effectiveness of blast walls and the Army was interested in the protection offered by trenches. The Royal Air Force would provide the ordnance needed for the study. The results were very positive and local limestone (as well as its use in local construction) proved an effective material against high explosives. Trenches were also dug, 6 feet deep and 4 feet wide at various distances. Rabbits placed inside the trenches and buildings survived unscathed.
The bomb detonated was a British 550 lbs bomb. However, the fact was that the explosion occurred inside a pit had some effect in absorbing and deflecting the pressure wave and shrapnel generated by the bomb, something which was also noted in subsequent references to the test. Nonetheless, it was reported that:
The conclusion to be drawn from the experiment is that the type of building in Malta provides very reasonable protection from all except a direct hit and that therefore persons would be well advised to remain indoors during an attack rather than run outside where they would be exposed to danger from splinters”. (FCO 141 8867).
This advice eventually became instruction to the public until the late 1930s. The rock-cut shelters all around Malta we are familiar with were far from the ideal all-round solution in the local government’s mind until the late 1930s. In 1934 and 1935 progress reports, Air raid shelters (as well as gas-proofed rooms within one’s homes) are only mentioned as part of Malta’s passive defence preparations in the “Vital Sector” (the harbour cities) and one in Hamrun. The evacuation of civilians to tents and accomodation outside of the “vital areas” was planned as early as 1935 together with the organisation of Malta’s passive defence which started off in 14th December 1934 with the first meeting of the ARP committee. The latter was addressed in great detail by a UK delegation of ARP and Chemical research representatives (Kirwan and Sumner) in September of 1935 (FCO 141 9725). With Maltese houses offering a sufficient level of protection against explosives, churches were deemed to be “solidly built” and the presence of priests highly beneficial to calm sheltering refugees. Gas was deemed a bigger and more likely threat. It was recommended to send samples of Malta stone to the UK for testing to determine the effect of gas on it (FCO 141 8463).
DO NOT PANIC AND ON NO ACCOUNT RUN as this is apt to lead to panic in others. STOP OTHERS PANICKING. PANIC IS MORE DANGEROUS THAN BOMBS”- Air Commodore for R.A.F. Mediterranean, 29th August 1935.
One cannot overstate that, for many years, gas was considered as the biggest and most probable danger in any future air-raid. After all, chemical warfare was normalised during the First World war and used during the Italian invasion of Abyssinia. Therefore, people were instructed to make gas-protected rooms in their homes. This was done by selecting a second floor room with wet blankets in doorways and windows, among other measures (FCO 141 11724). However, soon enough it was anticipated (after seeing then recent aerial attacks such as those against Barcelona in March 1938) that high explosive bombs would more likely be the enemy’s weapon of choice. Measures against aerial high explosive bombings were subsequently elevated to the same importance as those against gas attack (FCO 141 8763). As early as October 1938 the Royal Engineers reported that there was sufficient shelter for the population of Valletta and Floriana, referencing disused railway tunnels and already existing underground areas in fortifications which were already earmarked several years prior for this purpose. The Public Works Department carried out works to make them sanitary and gas-proof, apart from erecting blast-walls. One specific proposition was the sectioning off of the Railway tunnel using concrete walls to divide it into 24 sections apart from strengthening the air vents. By November of 1938, shelter was available for 14,000 out of 34,000 people in Valletta, while also estimating that 10% would have evacuated before any bombing occurred. The provision of shelter for people outside of Valletta was still in question (FCO 141 8763). Reinforcement of basements in countryside buildings was considered as well as steel Anderson shelters much like those used in the UK.
By 1939 the primary targets of a future war were clearly earmarked such as the harbour cities and especially the dockyard. Initial shelter construction would focus on those areas, protecting workers and the local population. Imperial funds were put into the approved shelter construction scheme and works began in Senglea. In September 1939 six rock cutters were sent from the UK for Malta towards this effort (CAB 106/491). It was known that the durability and effectiveness of shelters greatly depended on the quality of the rock in which they were cut. Testing of Malta’s limestone ability to withstand direct hits goes back as early as 1937 when high level bombing was conducted to determine the penetrative capacity of various bombs. It was found that 6 feet of penetration could be achieved even in good quality limestone (FCO 141 8763). Despite this, shelter construction of different types started slowly.
In December 1939 a special delegation from the civil engineering consultancy firm of Sir Alexander Gibb arrived in Malta to prepare plans for shelters in Valletta, Floriana and their suburbs as well as villages in the vicinity of aerodromes. The ‘Gibb’ scheme was recieved in Malta in April 1940 by which time shelters became an urgent matter to address. Tunnel shelters were recommended, similar to the ones that were already being built by the Public Works Department in Senglea. These tunnels would run consecutively next to each other and connected at intervals. Specific calculations were also provided for the rate at which people could enter such shelters (160 per minute) and aimed to provide shelter to any civilian in certain areas within 10 minutes. Water supply and air ventilation was also included in the design of these shelters. This deep-shelter plan was estimated to cost around 300,000 pounds and take 3 years to finish (CAB 106/491).
The plans never materialised completely. However, work did start, going as far as amending the 1939 defence regulations to eliminate the need to ask for permission before digging under houses. When the first bombs were dropped over Malta on the 11th of June 1940, the harbour area was evacuated and people living in remote areas were encouraged to dig trenches or take shelter in their own homes. In this initial period, the long-term deep shelter scheme had to be abandoned. Instead, a lot of effort was put into the construction of temporary shelters: strengthening buildings and identifying rooms or cellars in houses suitable for this role. Caves and catacombs also became adequate air raid shelters (CAB 106/491). By late 1940, strutting and shoring were some of the means by which reinforced basements and designated rooms became strengthened air-raid shelters. At this time only one hospital had a rock-cut shelter but many sensitive buildings would get their own soon after (FCO 141/9064).
Even without the costly deep-shelter scheme, the expense of constructing blast walls in front of all doorways was considered too expensive. The fact that Malta’s houses were constructed from limestone and built on solid foundations led UK researchers to predict that bomb damage would largely only affect the immediate point of impact (FCO 141/11758). Bricked-up doors and windows with small gaps were selected as a viable alternative to make more rooms and buildings resistant to bombs. Another experiment also carried out in Għallis in 1935 recommended that brown paper (preferably pasted on both sides) provided sufficient protection against shattering (FCO 141 8390). Sandbags were also purchased and distributed to make rooms ‘splinter-proof’ by blocking windows such as those of operating theatres in various hospitals.
Nevertheless, sandbags, trenches and blast walls would not suffice to protect Malta and its supplies. Shelters were constructed either above or below ground. ‘Caterpillar’ or ‘synthetic sphinxes’ shelters started to pop up near popular streets and bus-routes, in fact they were also referred to as ‘road-side’ shelters. It would take the form of one long trench (approx 20-30 feet long and 2 feet wide) covered by a thick superstructure and one curved entrance. An escape shaft was located on the other end covered with a blast wall. Some were constructed using wooden beams on which earth and other material could be piled on.
Just before the outbreak of war, shelter construction was distributed across the services to ramp up construction works. Later on, work would be further split up between a dedicated Shelter Construction Department (SCD) and the Public Works Department (PWD), each employing their own labourers. In August 1940 Mr. Navity was appointed Supervisor of Shelter Construction. He, together with help from the Superintending Civil Engineering and Public Works departments, would quickly get to work on setting out a comprehensive shelter construction plan for each village (placed in ‘zones’) based on population statistics. Lija and Qormi were two of the first villages to be incorporated into the new construction scheme which started off in September. Cellars and strong rooms were incorporated into the plan, sometimes connected through rock-cut tunnels. However, it was noticed that people preferred to stay in the passageways rather than the reinforced rooms. Special types of steel-strengthened concrete trenches (burster slabs) were also met with disapproval and people refused to use them. The public felt safest in rock-cut spaces (CAB 106/491).
To this end, between late January and November of 1941 all effort was dedicated to the construction of rock-cut shelters, forfeiting plans for other types and schemes. It was realised that, in fact, the best protection is afforded by rock-cut shelters which, unfortunately, were the most expensive and time-consuming type of shelter to produce. However, they had the advantage of requiring no concrete or steel reinforcements at all and, being underground, could be constructed even during air-raids (once the entrance was completed).
We have to concentrate on that particular kind of shelter. I am far from saying that the other types of shelters which we have been constructing are not every bit as good, but still the people do not like them and what we want to do is to give them confidence in the shelter that is being provided for them. For this reason we had to turn over from the type of shelters which we are building to concentrating on the provision of rock shelters in every place in which those being built. That means a certain slowing down in some places of the tempo; and we have to counteract that in every way by increasing the number of workmen who are employed and increasing particularly the supervision of them in order to so that work is continuous and efficient. We can only do that by taking the necessary powers to conscript labour and to organize it into effective and properly officered bodies of men” -Lieutenant Governor Dobbie to the Council of Government, 23rd January 1941.
Public rock-cut shelters were constructed as quickly as possible and were not always up to standard. However, it was planned to eventually upgraded them to withstand anything but a direct hit. Other shelters did not possess such planning. A lot of private shelters were dug without permission or proper planning causing time-consuming damages to nearby wells and sewage infrastructure. Despite this, the public was encouraged to dig shelters or extend the ones already constructed. Skilled labour was in great shortage. Training for miners was provided and tools manufactured. However, problems soon emerged such as people refusing to build anything but enough shelter for their family, ignoring advice from the SCD, and wealthy individuals paying very high wages to skilled labourers urgently needed elsewhere, eventually forcing Government intervention to secure workers. Both the SCD and the PWD would grow rapidly, employing thousands of miners between them and extending work to the sister island of Gozo. By November 1941, there was enough underground shelter space for the entire population; 270,323 people, each allotted approximately 2 feet of space (later increasing to 4), with room to spare for many more, not to mention the underground storage spaces for precious supplies brought in by convoys (CAB 106/491).
Later on, the real effectiveness of these ‘economic’ shelters revealed itself through experience. Shelters with less than 20 feet of rock cover were considered to be at risk of collapse from the pressure exerted when a heavy bomb detonated above them. It must have worrying when one realises that most shelters in Malta only had 15 feet of overhead cover (CAB 106/491). Several shelters, private and public, collapsed from a direct hit trapping or entombing several people, despite the efforts of the Demolition and Clearance Department to save individuals and salvage remains (CSG 01 1593/1942, CAB 106/495). In other instances shrapnel was the real danger. One particular post examination of such a case from 1942 in Corradino revealed that 20 casualties were not killed from a bomb’s blast but by the debris which shot into the tunnel by a second bomb which landed nearby the first. One man had his skull fractured by door. These findings were reported to UK experts who, in turn, provided their advice. (HO 192/59).
In 1942, a report was issued on the effectiveness of Malta’s rock-cut shelters when compared to concrete or hard-chalk shelters in the U.K. The Ministry of Home Security advised on minimum requirements needed for a shelter to withstand the biggest possible threat: a direct hit from a 1,800 kg bomb with a delayed action fuze dropped from 10,000 feet. For a 2nd class limestone tunnel-shelter without concrete lining, it needed to be at least 60 feet below ground. This could have been reduced to 45 feet if 9 inches of reinforced concrete lining was also used. Space was the recurrent issue (HO 192/59).
In December 1941, Dr Sacco reported that apart from cracks in unsafe shelters, some had as little as two or three three feet of rock above them (Sitting no. 2, 2 December 1941). However, the prospect of digging shelters 40 feet deep for the entire population of Malta was simply too big a task (CO 968/7/10). Shelters were deemed the single most important factor maintaining the public morale. Mr Acheson had noted in September that “As long as the people have confidence in the shelters and are fed, there is little to fear.” However, despite offering inadequate protection against all possible threats, people were managing with 15 foot deep shelters and the colossal task of constructing deep shelters, even in particularly vulnerable areas, was abandoned. Moreover, the Government did not want people to think their rock-cut shelters were unsafe. When asked for his opinion, Lord Gort himself sent a telegram on the 1st of October 1942 to the Secretary of State for the Colonies advising against the undertaking of a deep-shelter construction project, stating that out of 2,000 public shelters only 36 were damaged, of which only 3 were penetrated. The risk of losing the public’s confidence in shelters was too great (CO 968/7/10).
The programme of shelter construction would gradually reduce naturally as air-raids ebbed away from the island. After the worst of the bombing in April and May of 1942, SCD and PWD workers were reassigned on demolition and clearance works as well as on other construction projects. Many years later the experience and lessons learned from underground construction during the war were certainly remembered and applied. Many military and civilian facilities for administration and storage would be built underground with adequate concrete protection from future threats.
By Nikolai Debono, on behalf of Battlefront Malta
All references from The National Archives, London, TNA, CO 968/FCO 141/HO 192/ CAB 106 series except for CSG 01 which refers to The National Archives of Malta, NAM.
Additional facts and information on Shelters in Malta
Lord Strickland advised on the effectiveness of underground rock-shelters as early as 1935, going so far as building one under the offices of the Times of Malta (CAB 106/491).
On the 29th of September of 1935 Mr. G.D. Kirwan, a principal in the ARP Department in the UK and Major A.T. Sumner, Assistant Superintendent, Chemical Defence Research Department, arrived in Malta to create a comprehensive report on the organisation of Passive Air Defence measures. They went into extreme detail, pointing out the need for camouflage in pumping stations, the setting up of gas decontamination centres, and reserves of equipment for search and rescue in collapsed buildings after air-raids. The island was split into three zones according to the required intensity of Passive Defence measures (FCO 141 8735, 8390).
The early passive defence schemes stated that the air raid warning would be announced by fireworks from the top of Castille and sirens from St James Cavalier, St, John’s co-Cathedral and the Parish churches were recruited to signal all-clear using their bells (FCO 141 8463). Lanterns or maroons at ten second intervals would be used (FCO 141 11724).
Early on in the war the SCD and PWD co-operated to organise demolition gangs. The PWD loaned several demolition gangs to the ARP, falling under the latter’s direction for the initial salvage efforts in emergencies. Eventually in February 1941 a new department for Demolition and Clearance was created since the PWD had too many other responsibilities (CAB 106/495).
The wooden logs used to make caterpillar shelters were said to have come from ‘prized cargo’ (CAB 106/491).
The heavy rains of 1940 caused some of the earthen walls of burster slab trenches to collapse. This further reduced the public opinion on the safety of such shelter designs (CAB 106/491).
Luqa, Safi, and Mqabba very quickly built their own rock-cut shelters, having the island’s largest concentration of quarrymen (CAB 106/491).
The estimated cost of shelter construction was estimated to be around £600,000 in November of 1941, equivalent to £25,417,323 today (CAB 106/491).
The effect of Malta’s limestone buildings meant that a lot of debris was generated from collapsed buildings in narrow streets. This fact was already known and predicted in 1935 (FCO 141 11758).