After the Wehrmacht occupied the Channel Islands on 30June 1940, they assessed the existing defences to determine if they would be of use. The Germans found the Islands' fortifications antiquated and woefully inadequate for modern warfare.
Because the Germans expected to invade the United Kingdom in the autumn of 1940, they decided that expenditure on defences for the islands would be a waste. Initially the Germans built only feldmässige Anlage (field-type construction) positions. By 1941 the prospect of conquering Britain had decreased and the probability of an eastern war increased, requiring defences to be built to reduce the number and quality of troops required to defend the western ocean areas. Whilst the Luftwaffe and Kriegsmarine had their roles in protecting the islands from the Allies, the occupying forces put their main effort into land defences aimed at repelling a seaborne or airborne assault.
The resulting construction work in the Channel Islands was extensive; it required thousands of workers and massive supplies of cement and steel. Tiny Guernsey received special treatment. It had the largest artillery pieces in the Channel Islands, tanks, and 12,000 troops: one soldier for every two civilians on the island, compared to France which had a 1:80 ratio, or higher.
Fortify the Channel Islands On 2 June 1941 Adolf Hitler asked for maps of the Channel Islands; these were provided the next day. By 13 June Hitler had made a decision. He ordered additional men to the Islands and, having decided the defences were inadequate, lacking tanks and coastal artillery, he instructed the Organisation Todt (OT) to undertake the building of 200-250 strongpoints in each of the larger islands. OT, formed in 1933, was a construction organization that organised and supervised the work of a number of engineering and construction companies, as well as supplying a large labour force.
The "Westbefestigungen" (Inspector of Western Fortresses) was given responsibility for oversight and was required to generate bi-weekly progress reports.
On 16 June 1941 Hitler's instructions to reinforce the islands were transmitted there from Oberbefehlshaber West; the rationale was that an Allied attack "must be reckoned with" in Summer 1941.Russian State Military Archives, Inventory 500, Documents of the OB West.
German engineers had in 1938 and 1939 improved the Westwall or Siegfried Line (the defensive line facing the French Maginot Line), using 500,000 OT workers. They therefore had a high level of skills and quickly worked out the details of what was needed.
Construction Regelbau The Regelbau (standard build) system used books of plans for each of over 600 approved types of bunker and casemate, each having a specific purpose. The designs had been updated as captured enemy fortifications were examined; some were even tested to destruction for effectiveness. The German designs incorporated certain standard features such as entrance door at right angles, armoured air intake, 30mm steel doors, ventilation, telephones, internal walls lined with wood, and an emergency exit. There were over 200 standardised armour parts. Each area in the Islands was examined and priorities for construction set.
Wehrmacht defence works fell into three categories: Feldmässige Anlage (Field-type constructions) Timber and soil with 40 cm concrete ceiling if cement was available. Verstärkt feldmässig or "Vf" (Reinforced field-type constructions) 1m reinforced concrete ceiling. Ständige Anlage or "St" (Permanent constructions) minimum 2m ceiling and walls.
Festungspionierstab 19 (Fortress Engineer Staff 19) arrived in Guernsey in July 1941, to make plans for the construction works. A visit by Dr Todt, who was also Minister of Armaments, took place in early October.
Work would be split in accordance with Dr Todt's construction orders for the Channel Island works. Individual troops – field fortifications, slit trenches etc. Divisional engineers – mines and flamethrowers Army Construction Battalions – reinforced constructions to provide protection of “Vf” Reinforced field-type constructions quality Fortress Engineers and Fortress Construction Battalions – mounting heavy weapons, some tunnelling, reporting, maps, supervising OT – most tunnelling, quarrying, railways, roads, loading and unloading ships, supervising civilian construction firms, controlling civilian labour and “St” fortress type constructions.
The plan was finalised and submitted to Hitler. The original defence order was reinforced with a second order, dated 20 October 1941, following a Fuhrer conference on 18 October to discuss the engineers' assessment of requirements. The outcome was a decision to provide for the “permanent fortification” of the Islands to make an impregnable fortress to be completed within 14 months. Festungspionierkommandeur XIV was created to command the project of fortifying the Channel Islands. The OT organisation designated the Channel Islands work area as Insel Einsatze.
The work would continue as planned, despite the death of Dr Todt in a plane crash in February 1942. Albert Speer replaced Todt.
Construction workers Fortress Engineer specialist sub-units such as Compressor, Mining, Rock Drilling, etc., would move between the Islands as required. OT would carry out the majority of the work.
Supervisors and OT labour was supplied to German construction companies, ten of which operated in the Channel Islands. Skilled labour was recruited as volunteers from countries that had been overrun by German troops, including the Netherlands, Belgium, and France to top up the thousands of German workers. These employees were paid and provided with accommodation, better food, time off, leave and comforts. German OT wore OT uniforms; civilians from other nations wore civilian clothes. OT gave Guernsey the code name Gustav.
The manual labour would be provided using Gastarbeitnehmer (guest workers), Militärinternierte (military internees), Zivilarbeiter (civilian workers), Ostarbeiter (Eastern workers), and Hilfswillige ("volunteer") POW workers. Volunteer and conscripted labour would receive much better treatment than would forced labour. The forced labour came from the millions of prisoners taken during Operation Barbarossa, and arrived in the Islands in late 1942. Other sources of labor were Poland, French camps full of Spanish Republicans who had fled Spain after losing the civil war, and 1,018 out-of-work French North Africans from Algeria who were living in the south of France.
It was not just men that became OT workers; a number of women also found themselves in work camps. Some of the workers were Jews; around 1,000 French Jews spent time in the Channel Islands. The lowest levels of manual labourers were treated like slaves. They were badly fed and clothed and were beaten and punished for minor offences; the Germans considered them expendable and worked some to death. Conditions in Alderney were the worst where for a period the SS ran some Alderney camps. Some of the OT supervisors were sadistic. Ninety-six known graves of these workers are in Guernsey and 397 in Alderney. Detailed death certificates were filled out and the deaths were reported to OT in St Malo.
Forced workers from overseas only had the clothes they were wearing when taken, often summer clothes. They were supposed to be paid 55 Reichspfennig an hour. If they were from the Eastern Bloc, a deduction of 55% was made to pay for the cost of overseas reconstruction. They worked 12-hour shifts, seven days a week, and were allowed one half-day a month off.
Local workers too were recruited. The OT pay scale would provide them with 60% more than the normal local wages, but a team of eight plasterers negotiated a pay rise so they were each paid £12 a week if they managed to plaster 35m² per 10-hour shift. This compares to the £2-10-0 a week offered by the States of Guernsey.
Preparations Fortress Engineers, Festung Pionier Stab XIX, established their HQ at Elizabeth College and stores were set up next to Vale Castle and Bulwer Avenue for timber, stanchions, camouflage paint, anti tank obstacles, steel doors, tank turrets, etc. Shops for joiners and locksmiths were set up.
Headquarters of the 7,000 strong OT in Guernsey was established at Sausmarez park in December 1941. The OT hospital was at Ruette Braye, its fuel depot at Grandes Rocques, and timber and cement stores at St Sampson.
Sourcing of materials and transport had to be organised. Barges and small ships were brought to the Islands to transport materials to supplement the two ships run by OT. The supply vessels needed escort and flak ships for protection.
Cranes and concrete mixers were sourced. A 90 cm gauge railway was constructed, running from the harbour in St Peter Port north to St Sampson and on to L'Ancresse, before running down the whole of the west coast to L’Eree.
Consumable materials were sourced: cement, steel, timber for shuttering, sand and aggregate. Guernsey had a major quarrying industry so had stone and crushing facilities available. Tunnelling also generated stone. The Island had sand pits, away from the coastline that had had the salt washed out. Beach sand and pebbles would be used as a last resort.
OT transport was brought to Guernsey, mainly French vehicles dating back to 1914, to supplement horse-drawn transport. Contractors brought equipment and vehicles. Five camps were built, however most OT workers went into requisitioned houses.
Fortifications
From October 1941 and especially throughout 1942, building works moved ahead rapidly in hundreds of sites.
Using the Regelbau standardized plans, each site was excavated normally using manual labour, sometimes needing explosives, the materials excavated generally being kept close by. Metal strengthening bars were wired together and the wooden shuttering was installed. It was necessary to pour the concrete in as continuous operation as possible to avoid joints that would weaken the structure. Holes through walls for ventilation pipes and cables, doorways and escape routes being put in before the concrete was poured. Massive prop supports were needed for the 2–3.5 metre thick ceilings.
Each location had defences and facilities to suit its specific needs, the thickness of walls, floor, and ceiling were standard. A few plans were modified to suit the local terrain. Fittings such as air purification systems, showers, gas proof doors, telephones, periscopes, and wiring were standardised. Some elements were stripped from the Westwall and Maginot Line, others manufactured specifically.
Artillery positions
Batterie Mirus was the largest artillery battery in the Channel Islands. Using four barrels taken from a 1917 Imperial Russian dreadnought captured in Norway and resting on platforms manufactured by Friedrich Krupp A.G., these 30.5 cm guns had a potential range of with lightweight high explosive shells, weighing 250 kg or with the heavier 405 kg armour piercing shells. The battery became operational in June 1942.
Ten other coastal artillery batteries, which included 1 x 15 cm SK C/28 and 1 x French 22 cm K532(f) at Jerbourg Point, run by Marine units, 3 x 21 cm Mörser 18 and 3 x French 22 cm K532(f) army units, all designed primarily to fire out to sea, were placed in open concrete pits so that they could turn 360 degrees. Bunkers for ammunition stores were constructed as were accommodation bunkers.
Battery Dollmann at Pleinmont is open to the public to visit; it has one of the four 22 cm gun pits and a number of trenches restored. It features accommodation bunkers and two fortress quality ammunition bunkers, all linked by deep, concrete-lined trenches. A command and an observation bunker completes the major fortifications. Its guns had a range of . Barbed wire, 2 cm Flak positions, a Tobruk pit, 150 cm searchlight, minefields, Pak40 anti tank gun, and a Freya radar supported the battery.