REGELBAU 501EINFACHER GRUPPENUNTERSTAND

REGELBAU 502DOPPELGRUPPENUNTERSTAND

Part 1

Photography, writing,design, layout, etc.

Jakko Westerbeke <jakko@xs4all.nl>http://www.xs4all.nl/~gurth/afv

Other imagesFront cover map is a section of British map

Holland 1:25,000 Sheet No. 14 S.W. (W) DefenceOverprint 28 Oct 44 in the possession of HuibWesterbeke.

Zoutelande map from Plattegrond GemeenteVeere by BV Uitgeverij Rijnland, used with per-mission nor commercial intentions.

Netherlands, Zeeland and Walcheren maps fromRoute 66 by ROUTE 66 Geographical InformationSystems, also used without permission and com-mercial intentions.

�Page� icon taken from one of KDE 3.0�s icon sets.

Technical stuffThe photographs in this net.book were taken

using a Fujifilm 6900Zoom digital camera, whilethe computer graphics were created withPOV-Ray 3.5 and the KPovModeler 0.20 front-endfor it. The document was laid out in PalatinoLinotype and Futura XBlk BT usingQuarkXPress 4.1 for Windows. The PDF was creat-ed with Adobe Acrobat Distiller 3.01 and workedon with Adobe Acrobat Exchange 3.0.

Copyright & distributionThis document is copyright © 2003 by Jakko

Westerbeke, all rights reserved. Unless otherwiseindicated, all photographs and other illustra-tions in this document are copyright © 2001-2003by Jakko Westerbeke.

This document may be freely distributed, on thefollowing conditions: that no changes or modifica-tions are made to the document in any way; andthat no profit is made off the distribution.

ThanksTo Stichting Bunkerbehoud, for the easy-going

permission to photograph and measure their type502 and 143 bunkers. See www.bunkerbehoud.com

Printing tips (read this first)This document is designed to be printed double-

sided, with the even pages going on the backs ofthe odd ones. It is for this reason that the photo-graphs on the odd pages, while their captions areon the even pages: printing out a large graphic onboth sides of a sheet of ordinary printing paper islikely to cause the paper to ripple, which is avoid-ed this way.

To print double-sided, you most likely will need toprint out the odd pages first, then put them back intoyour printer to print the even pages. You can selectwhich pages to print in the Print dialog that appearswhen you choose to print out the document.

Printing double-sided will require a bit of experi-mentation to make sure you get it right, butbecause of the many different types of printer inuse, no definite, all-encompassing instructions canbe given here.

When figuring out how to put the paper back into

the printer, the following points are what you needto pay attention to:

� The side of the paper the printer prints on;� The paper�s orientation in the printer (to which

side the top of the page points);� Whether the pages should go in with the first

page on the top or on the bottom of the stack.

Should you have access to a printer that can printdouble-sided as standard, just switch on thatoption and print the whole document in one go.

If you print to A4 paper (that is, if you live out-side of North America), you should not have yourPDF viewer resize the page to fit the paper, unlessyou notice a problem with parts of the photos ortext disappearing in the margins.

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This net.book contains photographs of a total offour different German bunkers, all located in thevillage of Zoutelande, on Walcheren island in thesouth-west of the Netherlands.

Historical backgroundConstruction of the Atlantikwall, the German

defensive line built on the European coastline fromnorthern Norway to the Franco-Spanish border,was begun in 1942. In essence, it was a response tothe German failure to invade Britain, the boggingdown of the German offensive in Russia, as well asof the USA entering the war on the Allies� side; theidea was that by fortifying the coastline, an inva-sion could be repelled with far fewer troops thanwould otherwise be needed, thereby preventing awar on two fronts.

The island of Walcheren was heavily fortified aspart of these defenses, with two main pur-poses in mind: the most important one wasthat the island guards the entrance to theWesterschelde, which is part of the estuaryof the river Scheldt and forms the mainapproach to the large port city of Antwerp,in Belgium. Inthe 1940s,Antwerp wasthe third-largestport in theworld, afterNew York andHamburg. Thesecond is thatVlissingen (orFlushing, inEnglish), one ofthe two majortowns on the island, had fairly extensive portfacilities as well.

This lead to the eventual construction of 207true bunkers, out of a total of 245 planned, inaddition to numerous lighter defensive works.To put this into perspective, Walcheren is aroughly diamond-shaped island, approximate-ly 13 by 16 kilometers in size�in other words, that isone bunker for every square kilometer of ground �

Many of these bunkers were built in the dunesalong the south-western and north-western shores,facing the North Sea, since any shipping toAntwerp would have to approach from that direc-tion. The area around Vlissingen was known as the

Seefront Vlissingen (Sea Front Vlissingen), andmany of these were for coastal artillery, either gunbunkers or their supporting facilities such asammunition bunkers, personnel quarters, or firecontrol centers.

This was also true for much of the rest ofWalcheren: all in all, six batteries of coastal artillery,all operated by the Kriegsmarine (navy), were builtinto bunkers on dunes and dykes, and additionalartillery (of the army, not the navy) was placed in-

land to support groundtroops in case of anAllied invasion. Threenavy batteries of heavyanti-aircraft guns werealso emplaced onWalcheren.

Other kinds ofbunker built includedradar systems andanti-aircraft platforms,as well as command

posts and housing for the groundtroops necessary to protect all this incase of invasion. Much of this belongedto the German navy, but the army (Heer)and air force (Luftwaffe) also built theirshare of bunkers.

Besides the Seefront, there was also the LandfrontVlissingen. The aim of this was to defend the townagainst an attack from behind, should an enemysucceed in landing elsewhere on Walcheren. The

result of this effortwas a roughly cir-cular array ofbunkers, runningclockwise from thedunes to the north-west of Vlissingento the south-easterntip of the island�tobe more precise,from the hamlet ofValkenisse in the

dunes (original plans started the line at Dishoek,closer to Vlissingen), to the town of Koudekerke,and from there to Klein Abeele on the WalcherenCanal. On the other side of the canal, it continuedfrom Groot Abeele to the Napoleonic fortressRammekens. This line is marked on the Walcherenmap on this page.

3

I n t r o d u c t i o n

Walcheren

Zeeland

Netherlands, ca. 2000

Landfront(approximately)

Type 502

Type 501

Stützpunkt

Meistersinger Stützpunkt

Lohengrin500 m

Introduction

4

Atlantikwall defensiveorganisation

Various classifications were used to describe theimportance and size of defensive areas, the small-est being the Widerstandsnest (Resistance Nest) thatwas normally defended by a single section of tenmen. Three or four Widerstandsneste made aStützpunkt (Support Point), usually defended by aplatoon of troops.

A number of Stützpunkte together could form aStützpunktegruppe (Strongpoint Group), whichseems mostly to have been a classification used forsome stretches of coastline between more heavily-defended areas. However, �separate� Stützpunktecould also be found in such places.

An area that was to be heavily fortified wasknown as a Verteidigungsbereich (Defence Area).The town of Vlissingen was one of some twentyVerteidigungsbereiche in Europe, and its afore-mentioned Seefront and Landfront were a directconsequence of this status. At least in theNetherlands, each Verteidigungsbereich had aKernwerk (Core) that consisted of a large number ofbunkers in a small area.

The classification used from 1944 for the largestfortified areas was Festung (Fortress), of which allof Walcheren was one. Another term used withFestungsbereich (roughly meaning �fortress area�)but this seems to have been a bureaucratic termwhose exact meaning is hard to pin down.

To give an idea of the kind of defences aStützpunkt could have, consider that all fourbunkers pictured in this book were part of twoStützpunkte in the village of Zoutelande, onWalcheren�s south-western coast. These werenamed Lohengrin and Meistersinger, after Germanoperas, as marked on the map on page 3, and had67 and 47 permanent fortifications, respectively,according to a post-war Dutch army survey.However, far from all of these were true bunkers(of which there were 15 in all in the twoStützpunkte); many were much simpler shelters orweapons pits built from concrete and/orbrick�though it is in addition to trenches, fox-holes, anti-tank obstacles, minefields, and relateddefensive works.

LiberationIn early October, 1944, the British Royal Air Force

bombed the Walcheren sea dykes in four places, inorder to flood most of the island, which is belowsea level. This forced the German defenders onto

higher ground along the edges of the island andthe villages in the interior. It also had the unfortu-nate effect of causing many casualties among thecivilian population, who had beforehand beenwarned by means of leaflets dropped from aircraft,but who had nowhere to go.

On the 1st of November 1944, a three-prongedassault was made by Canadian, British and otherAllied forces for the actual capture of the island.Canadian forces attempted to cross the dam con-necting Walcheren to the neighboring island ofZuid Beveland (which was already in Alliedhands), troops of the Kings Own Scottish Borderersperformed an amphibious landing in Vlissingen,and a similar assault was made in the village ofWestkapelle by Royal Marine Commandoes andNorwegians, French, Dutch and Belgians of anInter-Allied Commando unit.

The island was defended by some 10,000 GermanWehrmacht troops (mostly army and navy, plussome air force; there was no Waffen-SS presence),who put up a varied resistance to the Allied forcesattempting to fight their way along the edges of theisland. Most of the army troops were second-line,old men drafted to man fortifications (the 70thInfantry Division, nicknamed the �Stomach-com-plaint Division�), and so frequently gave littleresistance to the Allies, but the navy troops andsome army officers were quite willing to put up afight. Despite Walcheren�s small size, it took untilthe 7th of November for the German forces to sur-render, by which time only about half of the islandhad actually fallen into Allied hands.

Bunker museumSince the summer of 2001, one of the type 502

bunkers in Zoutelande has been opened to thepublic as a bunker museum, together with a type143 nearby. For those interested in visiting, it is theright-most type 502 shown on the map on page 3.

To get there, from the village center, follow theDuinweg street to the east; about a hundred metersafter hotel De Tien Torens, take the road to theright, up the dunes. The first museum bunker is onthe left, about halfway up the dune; to get to thesecond, go slightly further up the dune and takethe footpath to the left, then keep following it.

Note that the museum bunks are only open onSunday and Wednesday afternoons, May throughNovember.

5

The German type 501 bunkerwas designed in 1939, as part ofthe planned Westwall defencesagainst France�the Germancounterpart to the FrenchMaginot line. After construction ofthe Atlantikwall was started in 1942, thetype 501 was built there as well, although it waslater superseded by the type 621, which was rough-ly the same size but of more up-to-date design. Atleast 1,519 type 501 bunkers were built duringWorld War II.

German bunkernomenclature

German bunker designations consisted of aRegelbau (meaning approximately �standardisedconstruction�) number, in this case 501. The num-bers were allocated in series, with bunkersdesigned around the same time having similarnumbers. These bunkers also tended to share fea-tures of the general design, such as the way theinterior was laid out, or the design of the ventila-tion system. The 500-series was developed for theWestwall, but was also used in the Atlantikwall.

The Regelbau number was followed by a descrip-tion of the bunker�s purpose. Here, the latter is ein-facher Gruppenunterstand, which translates intoEnglish as �single section housing��in otherwords, this is a bunker in which one section¹ ofnine or ten men could live.

Bunker constructionGerman bunkers were made from reinforced con-

crete. After a site for a bunker had beenselected, surveyed and, if neces-sary, prepared, a floor waspoured from concrete. Onto this,wooden moulds for the interiorwere constructed from beams andplanks, and the reinforcementswere built up around them. Thesesteel reinforcing bars were spaced 25cm apart, putting about 50 kg of steelinto every cubic meter of bunker wall.Anything that had to be anchored into the

concrete was put into place atthe same time: steel armour

plates, firing ports, ventilationtubes, chimneys, etc.If the bunker had an escape shaft,

as the type 501 did, then that wouldbe built from bricks and covered with a

thin layer of concrete. Because the shaft ispartly built into the bunker�s outer wall, it

is likely that it was constructed at this time as well.The inside of the roof was also built together with

the interior fittings, by placing steel I-beams atregular intervals (always so that they spanned theshort side of a room, for strength) and putting steelplates between them. Use of wooden planks waspermitted if steel was not available, but due to thefire hazard they presented, wood was not the pre-ferred material.

Once all this had been done, an outer mould wasbuilt around the reinforcements and the concretepoured in. This was done in a single, continuousoperation that went on day and night, so as to cre-ate a bunker consisting of a single block of con-crete, without any seams or similar weak points.The impressions left by the planks on the concreteare very obvious on the actual bunkers, and alsoquite visible in the photographs in this net.book.

German bunkers could have two types ofcorners. One, as on this type 501, was sharp:the sides were simply built into a squareshape, and so were the curved roof edges

where they joined. This was fairly simple to make,as no complicated joints were needed.

A more complex, round shape was also used, ascan be seen in the photographs of the type 502

bunkers on page 19. Here, the whole cor-ner of the bunker wall was rounded,and the roof corners were built into a

spherical shape. The moulds forthis must have been much more

difficult to build properly, butthis style of corner is

stronger than thesquare type, and so was

more common.

¹ �Squad� in American terms.

Regelbau 501 � EinfacherGruppenunter s tand

11&19

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Regelbau 501: einfacher Gruppenunterstand

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Regelbau 501 describedAs explained above, the type 501 bunker

was designed to house a single section. Assuch, its main room is simple and rectan-gular, but the need to allow the bunker tobe defended against both attackers andchemical weapons made necessary anelaborate entrance that takes up a largeamount of space. The type 501 takes upapproximately 9×9.9 meters of groundarea, but of these 89 m², only 19½ m²are reserved for the occupants�lessthan a quarter of the total space. Ofthe rest, some 63 m² consists of walls,leaving the remaining 6½ m² for theentrance corridors, gas lock and doorways.

The whole bunker consisted of the followingparts or sections; the numbers refer to the planabove and the three-dimensional cut-open viewson pages 5 and 7.

b Entrance corridorThe only way into the type 501 is through

this entrance. It was located in the rearwall�that is, the wall that faced away fromthe direction the enemy was most likely to

come from�as this prevented enemy fire from land-ing directly in it, either unintentionally or by design.

The corridor could be closed by a metal bar door,which served to prevent enemy troops from enter-ing the bunker but did not obstruct the firing portfrom shooting at those same soldiers (see f).

One of the major differences between the 500-series of bunkers and its successor, the 600-series,is obvious here: in the 500-series, the entrance wasflat�that is to say, the bunker�s floor was at thesame level throughout. In the 600-series, however,the entrance was set mugh higher up in the wallthan the floor level, with steps leading down, inorder to lower the bunker�s silhouette.

c Decontamination nicheIn case of a chemical weapon attack, soldiers

would decontaminate themselves in this part of thecorridor before entering the gas lock. It is otherwisea dead end. A locker with chemical warfare equip-ment could be set up in this part of the bunker.

d Gas lockThe gas lock was a means to prevent chemical

weapons from entering the bunker itself, by pro-viding a place where the soldiers could be more

thoroughly decontaminated before goinginto the main room. The gas lock

also served as adefense against reg-ular attacks, as it hada strong outer door,made from 3 cm thicksteel, with a vision/fir-ing port in it.

This door was intwo halves, weigh-

ing almost 250 kgeach, allowing the

top and bottom to beopened separately (a lip

on the lower door pre-vented it opening further

than the upper one). Thereason for this was that in

case debris had spilt into the corridor, it might blockthe lower door but generally not theupper one,allowing the bunker�s occupants to get out anyway.

e Main roomThis is where the soldiers lived, and was normal-

ly fitted out with bunk beds, a table and chairs,equipment lockers, and a bunker stove, plus what-ever personal touches the occupants wanted to

add. This room also had a bunker ventilatormounted on the wall to provide fresh airand also to create over-pressure inside thebunker during a gas attack. This was a

hand-cranked device that drew air into the bunkerand, if required, through a filter.

The main room was separated from the gas lock byanother steel door, but much less elaborate than theouter door. It was in one piece, and consisted of thinsteel plates rivetted to a frame, instead of from amassive slab of steel. To create a gas-tight seal, a rub-ber gasket ran along the inside of the door frame,

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Firing port in detail

9.00 m

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Interior description

7

while a small, glazed peep holein the door itself gave a viewinto the gas lock.

f Firing portTo defend

against attack,nearly all Ger-man bunkers had

a firing port built into an inte-rior wall, giving a field of firestraight down the entrance cor-ridor. It consisted of a steel plate,3 cm thick, set into a hole in theconcrete of the wall. The plate had a firing hole30×22 cm large, and closed from the inside by a slid-ing shutter also made from 3-cm thick steel plate.This is shown in detail at the bottom of page 6.

g Escape tunnel & shaftIn case the gas lock�s outer door was com-

pletely blocked by debris (see page xx), anescape tunnel was provided in the type 501�sright side wall. This was only 60 cm wide

and 80 cm high, closed by a steel door on theinside, and opened into a brick shaft of 2 m diame-ter built onto the outer wall. Steel rungs on thebunker wall inside the shaft allowed the escapingsoldiers to climb up onto the bunker�s roof.

The shaft itself was normally filled with gravel, toprevent its use by the enemy; two brick wallsinside the escape tunnel prevented the gravel fromspilling into the bunker. When the tunnel was to beused, the soldiers would open the steel door,smash or pull down the brick walls, and let thegravel flood into the bunker.

The illustration at the bottom of this page showsa closer view of the escape tunnel�s layout whenseen from straight above, with the cut-outs in thesides for the brick walls.

PaintingContrary to popular belief, most bunkers were

not left in their unpainted, grey concrete colourduring World War II; the fact that they have thiscolour today is because the original paint has wornoff due to 60 years� exposure to the weather.

If the bunker was built in the open, a large part ofit was covered by earth, to both blend it into thesurrounding terrain and protect it from shellfire.The exposed concrete was then camouflaged withvarious painted-on patterns, the exact style

depending on the surrounding area. The basecolour was most likely dark yellow, as thisremains on parts of surviving bunkers. Other

colours used were darker, but from only black-and-white photographs it is impossible to

say what they actually were; greenand brown similar to those usedon vehicles are probable.The dark yellow paint extended

into the entrance corridor, in a trian-gle on the side walls from the top edge of

the doorway down to the floor. The rest of theentrance corridor was painted like the interior,asdescribed below.

On the other hand, bunkers built in villages andtowns, or near farms, were often disguised as civil-ian buildings. They received fake roofs, and evenchimneys, made from wooden beams, planks andchicken wire, and had doors and windows paintedonto their walls�often even with decorations suchas curtains and flowers visible �inside�. Althoughmost of the fake roofs are quite apparent in con-temporary photographs taken from ground level,they were effective against aerial reconnaissance.

On the inside, bunkers were paintedwhite; whether this was originally matt orgloss is now known, but all survivingbunkers the author has been in, were matt

white (note that the museum bunker�s interior hasbeen repainted gloss white). The floor was left asbare concrete.

Interior metal fittings were a green colour, whilehandles were painted black. Again, the museumbunker has these in gloss finish, but it is more likelythat during World War II they were actually matt.

Stencilled signs in black inside the bunker indi-cated the purposes of the various rooms, as wellas bunker identification numbers and warningsigns. On many surviving bunkers, these signs arestill visible.

Escape tunnel in detail

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Regelbau 501: einfacher Gruppenunterstand

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b Entrance & rear wall

Once you get close to it, this is the view youget of this particular 501. It is buried in abouta meter and a half of sand, so only a small partof the entrance is visible.

This side of the bunker faces away from thesea, and will therefore be referred to as therear wall. When the text refers to other sides,picture them as if you were standing in frontof the door, looking at the bunker.

The text above the door reads �Door die�which is Dutch and translates into English as�Through that��what it refers to, or whatword is missing, is anyone�s guess, but as thisbunker has long been used as a playground bylocal children (including the present author15+ years ago), it could be just about anything.

d Rear roof

Climbing the rungs leads up onto a smallpatch of bare roof, visible here. The dark partis the rear side of the roof ridge that is com-mon to nearly all these bunkers. Its function isto keep the soil on top of it�German bunkerswere almost invariably dug into the ground,or had earth banks built up against them, bothfor camouflage and to provide additional pro-tection from enemy fire.

c Metal rungs

From closer to the bunker, the metal rungladder is visible, with a length of nylon ropetied to it by someone, most likely again byplaying children.

The door is not in the center, but this is verydifficult to see with all the undergrowthobscuring most of the bunker.

Rear wall

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Regelbau 501: einfacher Gruppenunterstand

g Escape shaft ladder

On the other side of the shaft, it is much eas-ier to look straight down, because there is nocurving bunker roof that you might slip down.The floor visible at the bottom of the shaft isabout four meters down, but the shaft hasfilled up a bit since the war so it would havebeen somewhat deeper still originally. Thewhole thing is semi-circular, with a radius ofabout a meter. The rungs are made of muchthicker steel than those of the type 502, pic-tured on page 20.

10

e Roof corner

The only corner of this type 501 that is visibleis the right rear one. It is much sharper thanthat of two of the type 502s (see page 19),showing different methods being used to con-struct the molds into which the concrete waspoured.

f Escape shaft

This is what you see when you first approachthe escape shaft from the roof of the bunker. Itis nearly completely overgrown, with bushesup to 1½ m or so high around it, so if thewhole area wasn�t off limits, it could be dan-gerous. (The author once nearly fell in whencoming from the other side, only seconds afterwarning someone else to watch out for thehole in the ground �)

Corner & escape shaft

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Regelbau 501: einfacher Gruppenunterstand

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h Escape shaft interior

As should hopefully be apparent, this photowas taken from inside the shaft, looking up atwhat�s visible of the sky. The picture was takenfrom as low down in the shaft as was feasible,to get as much of the shaft on it as possible, butit still does not really do it justice.

The walls of the shaft consist of a roughly-applied layer of concrete over bricks, whichshow in a few places where the concrete haschipped away.

When the bunker was in active use, theescape shaft was filled with gravel, which pre-vented both enemy soldiers and enemy bombsor artillery fire coming down it.

j Escape tunnel

A look into the escape tunnel shows the mainroom in the bunker, with junk left behind byplaying children. This tunnel is only 60 cmwide and 80 cm high (without the sand on thefloor), but currently has more room than themain entrance does.

The slots in the walls, visible at the front ofthe picture, are for the brick walls that wereput into the tunnel to keep the gravel in theshaft. Should the main entrance be unusablefor some reason (for example because it wasblocked by debris), the soldiers inside thebunker could pull down the brick walls and letthe gravel pour into the bunker�s interior, afterwhich they could escape through the shaft.

The tunnel was closed by a steel door on theinside�that is, the far side in this photograph.

i Entrance corridor

This is the part of the interior visible throughthe front door, but you have to get down ontothe ground to be able to look in. The metalparts are pretty rusted, but the original whitepaint is still visible.

The sign stencilled on the left wall readsVLISS-WEST 022-253, indicating the bunkerwas part of sector 22 of the Vlissingen-Westdefenses�that is, Stützpunkt Lohengrin to thesouth-east of Zoutelande�and was bunkernumber 253 in the Vlissingen-West network.

The firing port to defend the entrance isclearly visible, with the main room beingbehind it. To get there, you would have to turnright in the corridor, which leads to the gaslock. The corridor to the left is a niche in whichsoldiers could decontaminate themselvesbefore entering the gas lock, which is aroundthe corner on the right.

Interior views

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The type 502 bunker is avery similar design to thetype 501�in fact, it can befairly accurately describedas two type 501s graftedtogether side-by-side. Itsname reflects this: the 501 isan einfacher Gruppen-unterstand (single section housing), while the 502is described as a Doppelgruppenunterstand (doublesection housing).

Just as the type 501 was superseded by the 621,the 502 was replaced by the later 622 in theAtlantikwall. At least 1,718 type 502s were built,however.

Regelbau 502 describedAlthough the type 502 is very similar to the type

501, it differs in many details�besides its largersize, of course. The numbers refer to the map andcut-outs on this and the following pages.

b Entrance corridorThese were almost identical to those in the

type 501, though the corridor on the right wasessentially a mirror image of that on the left.However, this is only true for the basic shape,

as the two differed in details. As the plan shows,there was a niche in the right-hand wall in both cor-ridors; this was probably for installation of a radio orfield telephone, as a kind of drainpipe went straightup from the niche to the roof, though which a radioantenna could be extended. At the same time, a slotcut into the wall from the niche to the bunker�s outerwall, with a pipe running through it (this is visible inthe photos on page 21), either for electri-cal supply or for field tele-phone cables.

c Decontaminationniche

As in the type 501, the cor-ridor has a dead end thatwas intended be used as adecontamination niche. Oneor both might have a lockerwith chemical warfare equip-ment for just this purpose, but a

peat toilet might also be setup in them. In the type 502bunker that has been fitted

out as a museum (see p. 18and on), the niche on the left-

hand side has a drain set intothe floor, while the right-hand one

does not. Because the other type 502s pictured inthis net.book are inaccessible, it is not clear if thiswas a feature of all these bunkers, or just of thisparticular one�bunkers were similar to shipswhen it came to building them: no two are exactlythe same, even though they were made to the samespecifications.

d Gas lockBoth corridors gave access to the central gas lock,

which had a two-piece, armoured door on eitherside as well as a gas door to close it off from themain rooms.

Note that the gas lock was asymmetrical: the gasdoor was offset to the right, and so was the extraniche in the wall opposite that door. In the muse-um bunker at least, the gas lock�s floor was pouredhigher than those of the surrounding rooms andcorridors, being made level with the bottoms of thedoor frames.

e Main roomsBecause this bunker type was intended to

house two sections, it has two main roomsseparated by an 80-cm-thick concrete wall.There is no door between the two, or even a

step in the floor; the dividing wall simply ends inthe middle of the room. Although

these two room could havebeen made into one by leav-ing out this wall, thereby cre-ating a little bit more space,

the reason for it beingthere anyway isbecause the Germanarmy had decided

that bunker interiorrooms should not span

more than 7 meters�so as toavoid weakening the structure. This rule

was not applied to navy or air force bunkers, how-

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R e g e l b a u 5 0 2Doppelgruppenunterstand

Modelling the Regelbau 501 & 502 bunkers

15

ever: the navy thought nothing ofinstalling coastal artil-lery into roomsspanning fifteenmeters or more, forexample, whichwould have beenunacceptable to thearmy.

f Firing portIn front of each

of the twoentrances was adefensive firing port,

of the same design as that used for the type 501; aclose-up drawing can be found on page 6. The fir-ing ports were mirrored, however, by the simpleexpedient of installing one upside-down comparedto the other.

g Store roomThe original purpose of this room was for

the installation of a steel observation cupolain the bunker�s roof, but even when the type502 was built in the Westwall, this was

rarely fitted. In the Atlantikwall, it was apparentlyeven rarer. Instead, the room was used for storage,most likely of food�the museum bunker has theroom fitted out with shelves full of tin cans, whichseems appropriate considering the rule that eachStützpunkt or Widerstandsnest had to be self-suffi-cient for up to 56 days (although this was laterreduced to 30 days).

Modelling the Regelbau 501& 502 bunkers

Models of bunkers are fairly thin on the ground,and as far as could be determined, no models of thetypes 501 or 502 are commercially available.Luckily, they are of a very sim-ple design that should not bevery difficult to produce frombasic materials.

An easy way may be to builda mould from Lego bricks tocast a square block of thebunker�s outer size, with a pro-trusion going into the bunker toform the entrance corridor.After coating it with a mouldrelease agent (some kind of

kitchen oil will do as well), you cancast plaster into the mould; once thishas set, the mould can be dismantled,

after which you can cut, file andsand the plaster into the final

bunker shape.With a little more fore-

thought, it should not bevery difficult to make a

mould that will leave theinside hollow, in order to save plas-

ter and/or weight, or to also add the side-ways corridor�part of which is visible throughthe front door.

To easily incorporate the plank impressions thatare so obvious on the outer walls, a more difficult,but also more accurate, way to build a bunkermodel could be to create a mould from woodenslats and strips, replicating in miniature the way inwhich the real bunkers were built.

A different way to create a bunker is to build itfrom clay. This can be rolled into flat plates by theplacing two wooden slats of the wall�s intendedthickness next to a blob of clay, and then using awooden dowel or some similar object to roll itdown to that thickness. The sections can be�glued� together with water, while the plankmarkings can be made by pushing a strip of woodinto the still-wet clay. Remember, though, that clayshrinks as it dries, so this has to be taken intoaccount when determining the model�s size.

A major mistake made by many modellers is inthe way bunkers are finished and placed in a dio-rama or on a scenic base. Plenty of models arepainted in concrete greys and placed on top of theground, or at best partially dug in. During WorldWar II, the real bunkers were dug in as far as pos-sible, leaving only entrances, firing ports, observa-tion devices and ventilation shafts exposed. Even

on flat ground, amound wasthrown up aroundthe outside.

The concreteparts that wereleft exposed werepainted in cam-ouflage patterns,about whichmore informa-tion can befound on page 7.

14.80 m

9.5

0 m

bb

cc d

ee

gf

f

b

b

gc

c

df

f

b

2 m

2 m0.80 m

2 m

28-

29

28-

29

Regelbau 502: Doppelgruppenunterstand

16

b Rear wall right

One of the three type 502 bunkers remainingin Zoutelande, the only remaining bunker ofStützpunt Meistersinger. Most of its right rearwall is shown, with the angled walls built ontoboth sides to hold the sand of the dunes backso that it would not slide down in front of thebunker. This is the only type 502 in the villagethat has these walls.

Civilians were allowed to shelter in thisbunker during the Allied assault on Walcherenin November 1944, and the only German casu-alty during the liberation of the village fellhere as well�an Unteroffizier shot by his ownmen, who didn�t feel like offering resistance toA Troop, 48 Royal Marine Commando �

The fence at the top of the bunker is a modernaddition, but the ridge underneath it is not.

d Rear wall left

The left front of a second type 502 bunker,about five to ten minutes� walk from the oneshown above. This one, however, was part ofStützpunkt Lohengrin.

It has had its entrances closed up, making itsinterior inaccessible. Normally, rungs wouldlead up to the roof on both these bunkers, butall of them have been cut off at some point inthe past. This photo shows precisely wherethey were, though.

The ground in front of this bunker is abovefloor level, as is obvious from the visibleheight of the doors.

c Rear wall left

The other part of this type 502�s rear wall,which faces landward�right behind thebunker are the dunes, and behind those thebeach and sea.

The doors of this bunker are not original, buthave been installed to keep people away fromthe materials stored inside. Note that the con-crete beams that form the edges of a �path� tothe doors are actually ribs from a World War IIGerman concrete anti-tank obstacle.

The effects of almost 60 years� worth of expo-sure to the weather are very obvious; bunkersduring World War II would not have lookedthis weathered, but were generally painted ina camouflage pattern. Wartime photographs ofthis particular bunker show it was painted in apattern of sand and one or two darker colours(probably green and brown) in large patches.Plant shapes were painted on to further blendit into the surrounding dunes.

Rear wall (1)

17

c

b

d

Regelbau 502: Doppelgruppenunterstand

18

e Rear wall right

Due to the blocked-up entrances and lack ofmetal rungs, this bunker has a very clean outerwall that shows its basic shape to advantage.Comparing its air inlets to those in the otherphotographs on this page shows they are verydifferent: set back into the wall, instead ofbeing flush with it.

This bunker�s roof is easily gotten onto, as itis sometimes used in summer as an auxilliaryparking lot for a hotel nearby (the house visi-ble in the background is not that hotel), but asthe roof is covered by grass, there is not muchpoint in taking pictures of it.

g Left entrance

This is a third type 502 bunker, less than ahundred meters from the other one on thispage, and is the one that was opened as amuseum in the summer of 2001.

The type 502 bunker has two entrances in itsfront wall; the left-hand one is shown here,with the metal rungs leading up to the roof.Though rusted, bent, and in some cases bro-ken, these are still strong enough to support aperson�s weight.

The paint inside the doorway is not original,but is applied in the colours and pattern thatwere used in World War II.

f Roof corner

The left rear corner is exposed, showing acompound curve that must have been difficultto create a wooden mould for. The roof ridge isalso just visible.

Rear wall (2)

19

f

e

g

Regelbau 502: Doppelgruppenunterstand

20

g Right entrance

This is the right-hand entrance, again withrungs for roof access. This door is much closerto the center of the front wall than the otherone is, because of a store room that is incorpo-rated into the wall on the right-hand side ofthe bunker.

i Outer door

The outer doors of German bunkers weremetal grates, made from five steel bars heldtogether by some steel profiles. The reason forthis is the firing port in one of the interiorwalls, visible behind the door in the photo-graph. By constructing the door like this, itkept the enemy from entering the bunker, butat the same time did not prevent the defendersfrom using the firing port against anyone try-ing to open the door.

h Metal rungs

Shown here is the ladder of metal rungs, andthe overgrown bunker roof. A low concreteridge can be seen at the top, which stops theloose soil (that is to say, the sand held togetheronly by the plant roots) from sliding off. Notethe rounded shapes of bunkers made frompoured concrete, and the imprint of the wood-en planks used to make the mould for it.

21

h

g

i

Regelbau 502: Doppelgruppenunterstand

22

j Air inletThis is one of the two air in- or outlets for the type

502 bunker, as used on the first and third ones pic-tured. The cast steel grill is there to preventgrenades from being thrown into it by attackers;many German bunkers of later design than thetype 502 have an ingenious arrangement of twointake holes without grills, where throwing agrenade into the top hole will only cause it to rollout of the bottom one.

1! Identification panel

An identification panel was stencilled intothe doorway of each and every Germanbunker. This one denotes this to be bunkernumber 022-248 of the Vlissingen-West defen-sive network. This is the museum bunker, andthe panel is not original but has been repaint-ed together with the rest ofthe bunker�s interi-or�unlike the panel for bunker 022-253 that isfaintly visible in photo 8 on page 13.

1) Air inlet

The air inlet of the second bunker is very dif-ferent from those on the first, lacking the steelgrilles and being set back into the wall. It islikely that a large type of grille would havebeen fitted into this recess, but that it has beenremoved since the war.

Air inlets & registration panel

23

j

Regelbau 502: Doppelgruppenunterstand

24

1@ Gas lock upper doorinside

The gas lock can be accessed from bothbunker entrances, and is closed by a massive,two-piece, steel door on either side. Though abit blurry, this photo shows the upper door onthe right-hand side of the bunker, with its han-dles and peep hole/firing port.

1$ Gas lock lower doorinside

The lower door has fewer fittings than theupper one, these being limited to a handle forpulling it shut, a lever to secure it, and a hookfor hanging something on (probably a padlockwhen that is not in use).

1# Gas lock upper dooroutside

The outside of the upper door is shown here,this time on the left-hand side of the bunker(that is, the opposite of the door in photo 12).

The gas lock doors are in two sectionsbecause of the chance of debris falling into thebunker. This could block the door, so by mak-ing it in two parts, the designers tried toensure that at least the upper part of the doorcould be opened to let the soldiers escape.

Doors (1)

25

1#

1@

1$

Regelbau 502: Doppelgruppenunterstand

26

1% Gas lock lower dooroutside

This is the outside of the bottom door, on theleft-hand side. Although details of the doorare difficult to see (but there aren�t many), thisphoto shows that the wall has its corner bev-elled off; this is not so soldiers can carry largeobjects inside more easily, but so that the blastof an explosion outside will catch the edge ofthe door, and so push it shut to protect thetroops inside the bunker.

1& Interior gas lock door

Moving inside the bunker�s main space now,this is the inside of the door which separatesthe gas lock from the living quarters.

The colored pipes are part of the ventilationsystem, with the color denoting which direc-tion the air flows through the pipe, and/orwhether it has been filtered or not.

1^ Outer door

Beyond the gas lock is the outer door, in thiscase the one in the right entrance, seen fromthe inside looking out. The purpose of the tophinge is not entirely clear, as there is no corre-sponding one at the bottom of the wall.

Doors (2)

27

1^

1%

1&

Regelbau 502: Doppelgruppenunterstand

28

1* Firing port

A view of the firing port that covers the leftentrances; a second such port covers the otherentrance. It is constructed entirely from steel,the main plate being 3 cm thick and anchoredinto the concrete wall. The slider is also 3 cmthick, and can be locked into position bymeans of the mechanism that is visible in thephoto. The firing hole is aligned with the cen-ter of the entrance corridor, so the port as awhole is asymmetrical.

2) Telephone

A close-up of the telephone hanging on thewall. The electrical cables and their fixtures aremodern plastic ones, but follow the routes ofthe original lines.

The stove has an exhaust pipe that leads upinto the wall and from there to a chimney onthe roof. The closed-off pipe underneath it isfor cleaning the chimney: it is difficult to get abrush through a 90° angle in a pipe, so the onebelow it is set at only 45°.

The sign on the wall, at the extreme right ofthe picture, is for the benefit of visitors therestored bunker, and reads �Supply Room� inDutch and �Supplies� in German.

1( Store room door

The type 502 had a small �spare room� offthe living quarters, which was normally usedfor storage. In this bunker, it is closed by a setof steel exterior gas lock doors, which seems abit much for a simple store room.

The design of the type 502 actually called forthis room to be equipped with a periscope forobservation.

Firing port, store room door & bunker telephone

29

1(

1*

2)

Regelbau 502: Doppelgruppenunterstand

30

2! Living quarters

The right-hand room of the bunker is fittedout as it would have been during WorldWar II. This is the side of the living quarterstoward the right rear of the bunker. On the leftis a bunk bed, with a bunker stove next to it,and a telephone hanging on the wall. A table,chairs and stools like the ones shown herewere present during the war as well, but justabout everything else would have to be fur-nished by the troops themselves.

A bird cage, seen at the top of the photo, wasa common item in bunkers, and the keeping ofcanaries or similar birds was encouraged bythe German armed forces because they couldprovide a good warning of poison gas�eitherfrom an enemy attack or carbon monoxidefrom the stove.

2# Bunk beds

One of the bunk beds used by the Germansoldiers. It had room for three people, so twobeds per room let all six men in a Gruppesleep, though not with much room to spare:each bed is only some 175×65 cm large.

2@ Equipment locker

Lockers like this were used for storing thesoldiers� personal equipment. Here, it standsbetween two bunk beds, against the bunker�sfront wall. On top of it are a gas mask cannis-ter and a steel helmet.

Living quarters furnishings

31

2@

2!

2#

Regelbau 502: Doppelgruppenunterstand

32

2$ Air filtration device

This apparatus, hanging on the bunker'swall, is a hand-operated ventilation systemand air filter. The hand crank at the bottommakes it draw in fresh air from the outside,and circulate it around the bunker. In case ofan attack with chemical weapons, a filter couldbe installed to remove the chemicals from theair, and the device would then be used to cre-ate overpressure inside the bunker, therebypreventing the chemical weapons from enter-ing the building.

2^ Roof panels

Although it is not very visible, due to the lackof contrast on the white-painted ceiling, thisphotograph is an attempt to show the way theroof is constructed: steel I-beams with platesbetween them�the narrow strips are theflanges of the I-beams, and the pockmarkedareas between them the plates that have hadalmost 60 years worth of rust removed fromthem before being painted white.

2% Air filtration device

The filtration apparatus from the other side.Judging by the layout of the pipes, outside airis drawn into the filter through the yellowpipe, the blue pipes carry clean air from the fil-ter to the rest of the bunker, and red pipes (notviisble in this picture) vent air from inside thebunker to the outside world.

Bunker ventilator & roof

33

2%

2$

2^

34

Technical data501 502

Capacity 10 men 20 menFirst built 1939 1939Number built 1,519 1,718Materials needed

Concrete 356 m³ 629 m³Steel reinforcement bars 21,000 kg 40,500 kg

DimensionsWidth 9.00 m 14.80 mHeight 5.10 m 5.10 mDepth 9.90 m 9.50 mExterior wall thickness 2.00 m 2.00 mInterior wall thickness 0.80 m 0.80 mRoof thickness 2.00 m 2.00 m

ReferencesThe following references were used in writing the

text for this book.

Bremmers, J.C.P., Duitse Bunkers op Walcheren, pri-vately published, 1987 (no ISBN)

Crucq, Paul, Walcheren 1943-1944: Fotoverkenning& bombardementen, De Koperen Tuin, 1997, ISBN90.72138.72.4

Houterman, J.N., Walcheren Bevrijd: November1944, Middelburg, 1994 (ISBN 90-73921-03-1)

Rolf, Rudi, Der Atlantikwall: Die Bauten derdeutschen Küstenbefestigungen 1940-1945, BiblioVerlag, 1998 (ISBN 3-7648-2469-7)

Rolf, Rudi, Bunkers in Nederland, AMA/H. TalsmaUitgeverij, 1982 (ISBN 90 6474 015 1)

Rolf, Rudi, Typologie du Mur deL�Atlantique/Atlantic Wall Typology/Atlantikwall-Typenheft/Atlantikwall-Bunkertypen, AMA Uitgeve-rij, 1988 (ISBN 90 6476 045 3)

Sakkers, Hans & Hans Houterman, LandfrontVerteidigungsbereich Vlissingen 1942-1944:Atlantikwall, Vlissingens laatste vestinggracht, J.N.Houterman, 1997 (ISBN 90-73921-05-8)

Sakkers, Hans & Hans Houterman, Zoutelande inde Tweede Wereldoorlog: Een dorp aan de Atlantikwall,Stichting Bunkerbehoud, 2002 (ISBN 90-9015937-1)

Saunders, Anthony, Hitler�s Atlantic Wall, SuttonPublishing Limited, 2001 (ISBN 0 7509 2544 2)