The Zeebrugge and Ostend Raids
Benoit Strubbe
The Belgian ports o f Zeebrugge and
Ostend posed a serious threat to the Allied
forces durin g the First W orld War. Their
location, near the m outh o f the Thames and
the English Channel, w ould make these
ports the best-situated operating bases for
the German U-boat and torpedo boat fleet.
Moreover, Bruges was connected to both
Zeebrugge and Ostend via a canal. This
way a good hidin g place for the vessels of
M arinekorps Flandern could be developed
out o f range o f the British guns. During the
war, German ships operating from these
Belgian ports were responsible for one third
o f the tons o f sh ipp ing lost by the Allies.
At the same tim e, connections across the
Channel were essential to the A llies, not just
as a supply line to b ring in fresh troops but
also for com m unication and the provisioning
o f the British Isles. In response to the
German naval threat, the British Dover Patrol
tried to block the ports o f Zeebrugge and
Ostend in the night o f 22 to 23 A pril as w ell
as the night o f 9 to 10 May 1918.
To p ro te ct their U-boats, the G erm ans b u ilt a U-boat bunker in the Bruges harbour. It was
d em olished in the 1950s (Bruges C ity Archives, Z eebruggefonds)
Prelude
Zeebrugge and Ostend
in itially not targeted
The activities of M arinekorps Flandern
conducted from the Belgian ports had the
potential o f being strategically decisive. Yet
it to o k the British u n til late 1917 to realise
the seriousness o f the threat and decide to
blockade the ports o f Zeebrugge and Ostend
from the sea. To explain this hesitancy it is
necessary to take the overall developm ent of
the Great War in to consideration.
When WWI broke out in 1914, the
op tim istic idea was prevalent th a t the war
w ould be short. Both sides were convinced
o f a sw ift and glorious victory. The goal of
the German Schlieffen Plan to elim inate the
French land forces by sw eeping through
Belgium and Luxembourg, and to take the
Channel ports in France to fa cilita te an
attack on Britain was not achieved. The
German advance was halted by flo o d in g
part o f the Yser plain, am ong other factors.
The Germans had only succeeded in takin g
Zeebrugge and Ostend. At first, the British
did not wish to destroy these ports as they
assumed they w ould soon be recaptured.
VLIZ ■ DE GROTE REDE
2 0 1 3 • 36
The e n try o f the N a v y D ivision in Brussels (Im perial W a r Museums, Q 4 9 1 4 7 }
27
offensive failed, however. The front line
had only advanced a few kilom etres at
the expense o f hundreds of thousands
o f casualties. The plan to capture the
Belgian ports from land was consequently
abandoned. It was equally Im possible
to destroy the German subm arine bases
from the air due to the U-boat bunkers the
Germans had constructed In Bruges. By the
end o f 1917, British Vice-Adm iral Roger Keyes
therefore laid plans to close o ff the ports o f
Zeebrugge and Ostend from the sea.
The plan
A fe w G erm an to rpedo boats o f the Flanders Flotilla hea ding fo r the English coast
(Tolhuis Provincial Library/
Zeebrugge and Ostend could then be useful
for s up plying the A llied troops. The Germans
also considered these ports to be only a
tem porary stopover. Zeebrugge and Ostend
had fallen Into German hands relatively
Intact, but no defences were present and
the ports were not equipped for m ooring,
repairing and m aintaining a war fleet.
Flemish ports become crucial
The In itia l optim ism wore o ff as
manoeuvre warfare gave way to trench
warfare In late 1914. Many British ships
shelled the Belgian coast to prevent the
Germans from using the harbours o f Ostend,
Zeebrugge and Bruges. The Germans
understood th a t the conquest o f the Channel
harbours In France w ould not come soon.
The w ell-equipped port o f Antwerp, captured
by the Germans, could not be used since
using the Scheldt river would vio late Dutch
neutrality, which the Germans wanted to
avoid. For this reason, and fo r fear o f an
Allied landing, M arinekorps Flandern started
to expand the coastal and port defences In
and around Zeebrugge and Ostend. From
1915 onwards, several batteries were b u ilt
to repel the British shellings. It became
Increasingly d iffic u lt to shell the ports from
the sea. The German U-boats and torpedo
boats could now be deployed more often and
more efficie ntly from Zeebrugge and Ostend.
The British, to whom Channel shipp ing
was crucially Im portant, were In favour of
attacking the left flan k o f the front, close
to the coast, to be able to shell the Belgian
ports from land. The French, on the other
hand, wanted to focus on the Inland front.
The more experienced French got th e ir way,
the British plan was not Im plem ented for the
tim e being.
28
The threat o f the Flanders Flotilla
Up to 1916 the Im perial German Navy
had m ostly Invested In the High Seas Fleet
[Hochseeflotte) and the naval forces In
the Baltic, w hile M arinekorps Flandern
was subordinated. This a ttitu d e gradually
changed after the Battle o f Jutland (31
May - 1 June 1916). Although the Germans
had gained a tactical victory at this battle,
the British blockade o f the High Seas Fleet
was m aintained. Germany now realised
that this blockade w ould probably never
be broken and decided to Invest part o f the
resources earmarked for the main fleet In
the Belgian coast. They tem po rarily added
tw o torpedo boat flo tilla s to the M arinekorps
Flandern fleet. This enabled the corps to
take the offensive. This Increased and more
aggressive activity from the Belgian ports
gave rise to concern am ong the British
general staff. This concern grew when
Germany announced It would engage In
unrestricted subm arine warfare In early
1917. The German U-boats wreaked havoc
and spread panic In the North Sea and the
English Channel. In 1917 alone, h a lf o f the
to ta l tonnage o f Allied ships was sunk. It
was not ju s t U-boats th a t sunk more and
more ships. In late 1916 and early 1917 the
Germans organised several torpedo boat
raids In the Channel. The Flanders F lotilla
was now capable of d isru p tin g the v ita l
com m unication and supply line between
Britain and the Continent. This ever greater
threat made the British realise that a final
solution had to be found for the ports of
Zeebrugge and Ostend.
A new attem pt was made to break out
o f the trench deadlock at the Battle of
Passchendaele or Third Battle o f Ypres
(31 July - 6 November 1917). The British
high command aimed at breaking through
the front near Passchendaele In order to
eventually retake the Belgian ports. This
The British planned to block the ports of
Ostend and Zeebrugge by s in king obsolete
w arships filled w ith concrete across the
harbour channel. This way, the German
subm arines and torpedo boats would be
tem porarily or perm anently trapped In the
Belgian ports. It too k a great deal o f tim e to
draw up the plans fo r the raids. Especially
the old mole at Zeebrugge was a source of
great concern to the British. The Germans
had fo rtifie d this tw o kilom etre long arched
je tty enclosing the harbour w ith a series of
batteries tha t protected the entire port. To
make sure the blockshlps would enter the
harbour channel sm oothly, It was crucial to
divert the batteries on the mole. This
required British troops to land on the mole.
Three ships were converted to transport
these troops: the obsolete cruiser FIMS
Vindictive and the ferries FIMS Iris and FIMS
Daffodil. W hile the troops were landing, an
old subm arine had to blow Itse lf up under
the viaduct con n e ctln g th e m ole to the shore.
This w ould prevent German reinforcem ents
from com ing to the rescue of th e ir fellow
com batants on the mole. The three
blockshlps FIMS Thetis, FIMS In tre p id and
FIMS Iphigenia w ould In the m eantim e enter
the harbour channel more or less
undisturbedly and be scuttled at the
entrance. Of course, the Germans would see
these ships com ing from a great distance. For
this reason the British planned to use sm all
fast boats to create a smoke screen.
At first sight, the situa tion ln Ostend was
much sim pler. Several batteries and machine
gun nests protected this harbour as w ell, but
there was no arched mole. It therefore
seemed unnecessary for troops to land. It
seemed sufficie nt to scuttle the blockshlps
FIMS Sirius and FIMS B rillia n t across the
harbour channel.
A few crucial factors for the success o f the
attack plan were the weather, the tid e and
the tim ing. Calm weather was required for
the optim al deploym ent o f the sm all boats
and fo r the success o f the landing on the
mole In Zeebrugge. A landward wind had to
keep the sm oke screen In front o f the ships.
High tide was required fo r the troops to scale
the high m ole and for the heavily laden
blockshlps to enter the harbour channel
smoothly. Finally, all these conditions had to
be fu lfille d around m id nig ht to op tim ally use
VLIZ
IDE GROTE REDE]
2 0 1 3 • 36
the cover o f darkness. The changeable
w eather resulted In tw o cancelled attem pts.
The fleet put out to sea for a third tim e In the
evening o f 22 A pril 1918.
The Zeebrugge Raid:
22 April 1918
The tw o fleet segments sailed tog ether for
a few m iles and then th e ir paths parted. Both
fleets were planned to arrive at Zeebrugge
and Ostend sim ultaneously so th a t the
Germans would not have tim e to warn each
other, since the plans for the raid had already
fallen Into German hands durin g a previous
attem pt. When the Germans heard the ship
engines In Zeebrugge, they In itia lly thought
an airborne attack was coming. A fter a w hile
they realised that w hat they tho ugh t was fog
was actually a smoke screen, and they sent
up a few flares. They subsequently spotted
the British funnels and Im m ediately sounded
the alarm throu gh ou t the coastline. Flares
and searchlights Illum inated the entire mole.
The ship engines were now clearly audible,
but the ap pro a ch ln g fo g veiled the vessels.
British m onitors now began to shell the
German positions.
Just before m id nig ht a sudden gust of
wind blew away the smoke screen. The
contours o f FIMS Vindictive were now clearly
visible. The German batteries were In combat
readiness and opened fire. By the tim e FIMS
Vindictive had reached Its position alongside
the m ole, most o f the gangplanks specially
Position o f the blockships HM S Ip h ig en ia a n d H M S Intre p id in Z e e b ru gg e h a rb o u r
a fte r the ra id (Bruges C ity Archives, Z eebruggefonds)
ZEEBRUGGE KARBOUlf
nnn«h>™iDfC Kli' im UvdUuiini nui
pnpilh«' - f [ll-n-lL-JihJip l i '
f e j - l J r iT d A f
A r f W *I
f
~
f x u if io f lf
....
nf ¡L -„: t-.+ .fj
f r a t n f o i i q t p h a tJ H jrm i¡h r
Plan o f Z ee b ru gg e h a rb o u r w ith the po sitio n o f the blockships that w ere to close o ff the p o rt
(Bruges C ity Archives, Z eebruggefonds}
VLIZ
DE GROTE REDE
2 0 1 3 • 36
29
mounted for the landing had been destroyed.
Half of the soldiers who had waited on deck
for the landing had already been killed
or w ounded. Yet the ship continued her
course. HMS Iris and HMS D a ffo dil were also
approaching the mole. At about a quarter
past m id nig ht the first troops landed on
the m ole, w hile the British subm arine blew
herself up and destroyed the viaduct alm ost
sim ultaneously. The landing force destroyed
a few machine gun nests and a rtille ry pieces.
At about h a lf past m id nig ht the blockships
passed the mole. HMS Thetis, which led
the way, im m ediately came under heavy
fire. When entering the harbour, the ship
got entangled in the nets the Germans had
installed and ran aground. The crew scuttled
the ship prem aturely. HMS In tre p id and HMS
Iphigenia succeeded in reaching the harbour
entrance w ith o u t being noticed. Their crews
tried to position the ships across the harbour
channel as best they could before de tona ting
the charges. The raid appeared to be
successful and the British pulled out.
Ostend, an attack
in two episodes
HMS Sirius and B rillia n t encountered
more d ifficu ltie s when they approached
Ostend. The smoke screen was unexpectedly
blown away, so tha t the tw o ships were
an easy target. British m onitors shelled
the German batteries but were unable to
elim inate them. Heavy rain obstructed
th e ir view and the Germans had moved the
navigation buoy th a t marked the harbour
entrance. As a result, the tw o ships did not
find the entranceway and were eventually
scuttled outside the port, towards Bredene.
The First Ostend Raid was a com plete failure.
A second attem pt was made on 9 May.
This tim e HMS Vindictive, hastily repaired
after the Zeebrugge Raid, and HMS Sappho
had to block the harbour channel. HMS
Sappho never reached Ostend due to a
mechanical breakdown. HMS Vindictive did
make the journey, but once again find in g
the harbour entrance was not easy. A fter
steam ing back and forth near the harbour,
the ship eventually made it to the entrance.
HMS Vindictive entered the harbour under
heavy German fire. The damage sustained
durin g the first raid was exacerbated and
one o f the propellers broke down. Because
of the broken propeller, Vindictive had
d iffic u lty m anoeuvring. It soon appeared to
be im possible to position the crippled vessel
across the harbour channel. The comm ander
then scuttled the ship on site. The harbour
channel was only pa rtly blocked. This made
the second attem pt not an unqualified
success either.
Mission accomplished?
The tw o raids together claimed the lives of
over 200 British soldiers. The Germans only
sustained a few casualties. In light of the
losses suffered on the Yser front, this num ber
was acceptable to the British. But had the
operation been successful? How was this raid
perceived by both parties? What effect did
this operation have on the fu rth e r course of
the war? To find an answer to the question
w hether the British had achieved th e ir goal,
it is sufficie nt to check w hether the harbour
m ouths of Zeebrugge and Ostend had indeed
been closed off. In Ostend this was not the
case. HMS Vindictive had been unable to
position its e lf across the harbour channel
due to a broken propeller. In Zeebrugge, HMS
In tre p id and Iphigenia were better
positioned, yet a new channel was created
behind the blockships after only a few days.
U-boats and destroyers could therefore leave
the ports again soon after the raid. However,
the raids were a m oral v icto ry for the British.
They had not achieved the anticipated goal,
but the raids were prom oted as a British
victory. The British propaganda machine
depicted the entire operation as an
unqualified success. For weeks it was
claimed th a t the Belgian ports had indeed
been closed off, although numerous
photographs proved the contrary. The
participants were honoured for th e ir bravery.
No less than eleven Victoria Crosses, the
highest m ilita ry decoration in the United
Kingdom, were awarded for the exploits of
the British troops du rin g the raids. Moreover,
this operation had proved that the British
could breach the German coastal defences.
The raids certainly boosted A llied morale
after the disillusio nm e nt o f the Battle of
Passchendaele. The Germans, on the other
hand, m inim ised the results o f the raids. The
officia l report by Grand Adm iral Alfred von
Tirpitz states th a t little damage had been
done to the port infrastructure and tha t there
hardly had been any casualties. German
propaganda represented the British failure as
proof o f th e ir superior defence o f the ports. It
was pointed out that vessels could already
leave the ports after a few days. In reality,
German self-confidence too k a te rrib le knock.
The aim o f the raids had not been achieved,
but the British had succeeded in breaking
The sunken V indictive a g a in st the O stend p ie r (collection o f F re d d y Hubrechtsenj
30
VLIZ
IDE GROTE REDE]
2 0 1 3 • 36
through the German coastal defences several
tim es and had tem po rarily set foot on land.
As a result, the Germans constructed
ad ditiona l fo rtifica tio n s afterwards,
pa rticularly at the ports.
The threat eliminated
A fter the raids, the num ber o f Allied
ships sunk by the M arine Corps dropped
significantly. If this was not due to the raids,
what was the reason for this decrease? The
answer to this question Is complex. Several
British bom bings caused the floodgates to
function only sporadically un til the end of
June. But this only caused a tem porary delay.
However, the depletion of raw m aterials
In Germany after nearly fou r years o f war
resulted In the production o f new ships
fa llin g behind. In 1918 the A llies also applied
a few tested as w ell as new techniques on
a structura l basis to counter the subm arine
danger.
The Allies had reverted to using escorted
convoys In 1917. Convoying had proved
Its usefulness many centuries before. The
¡dea Is sim ple: merchant ships travellin g
tog ether under the protection o f a naval
escort. It Is surprising, then, th a t the Allies
In itia lly did not use this technique during
the First W orld War. The argum ents against
convoys were diverse. If a convoy ran Into
an enemy battleship, It did not have the
ghost o f a chance unless It was protected
by a ba ttleship as w ell. Having every convoy
escorted by a battleship was much too
expensive, however. Sailing In convoy also
meant tha t the group could only go as fast as
the slowest ship. Moreover, ships had to wait
In port u n til a new convoy put out to sea. The
Allies believed this w ould lead to loss o f tim e
and efficiency. Finally, the British thought
unloading an entire convoy would exceed the
capacity o f m any ports.
These argum ents were refuted one
by one, however. The British blockade of
German battleships prevented them from
m oving freely to attack convoys. The loss of
efficiency and tim e turned out to be greater
when a ship was sunk. And tim e ly notice
prior to the arrival of a convoy ensured
th a t the port In question could prepare for
unloading the ships. Convoys were gradually
Introduced and w ith success. Several new
techniques also showed great promise. In
late 1917 the British developed ASDIC, the
w o rld ’s first active sonar technology. This
apparatus em its acoustic pulses which
reflect o ff submerged objects and these
echoes are then received by the apparatus.
The apparatus determ ines the depth
(distance) of an object by m easuring the tim e
between e m ittin g and receiving a pulse. The
First W orld War also saw the developm ent of
the depth charge, designed for detonation at
a preset depth. Sonar and the depth charge
w ould both turn out to be very pow erful a n ti­
subm arine weapons.
VLIZ
DE GROTE REDE
2 0 1 3 • 36
This p a in tin g in Z e e b ru g g e C om m unity Centre depicts the Z ee b ru gg e ra id in a d ra m a tic m anner
(Decleer)
A British co n vo y o f the Royal N a v y z ig z a g s through a d a n g e r a re a in the A tla n tic O cean
(Im perial W a r Museums, Q 1 9 9 5 4 ]
Vice-Admiral Roger Keyes did not just
plan and lead the Zeebrugge and Ostend
raids, he also too k numerous other measures
to hinder German sh ipp ing In the English
Channel. For Instance, he had additional
anti-subm arine nets w ith mines Installed
and Introduced search-and-destroy patrols.
U-boats were then faced w ith the risk
o f being sunk by the patrols or g e tting
entangled In mine nets. A ll these measures
and circumstances made It Increasingly
d iffic u lt fo r the German subm arines and
torpedo boats In the Channel to disrupt
Allied supply lines.
31
Left: the o rig in a l m onum ent on the c o rn e r o f De M a e re la a n a n d Z e e d ijk in Z e e b ru g g e was p u lle d d o w n d u rin g the Second W o rld W a r a n d
taken to G erm any. The current m onum ent dates from 1 9 8 4.
Right: fragm ents o f the m ole w ith w hich H M S V indictive co llid e d , n o w lo ca te d on A d m ira a l Keyesplein in Z e e b ru gg e
(Tolhuis Provincial Library/
A boost to Allied morale
Current memorials to the
Zeebrugge and Ostend raids
The Zeebrugge and Ostend raids
certainly boosted the m orale of the Entente
Powers. The bravery o f the men who took
part and the subsequent reports in the
press renewed the faith o f the soldiers in
trenches in victory. This boost came just
at the right m om ent after the failure o f the
ba ttle o f Passchendaele and especially
after the frustrations and concern caused
by the German spring offensive. At the
same tim e, the actual effect o f the raids
was at first greatly overestim ated by the
A llies, in te n tio n a lly or unintentionally.
The sunken ships only caused moderate
interference. A fter a few days, the German
w arships were able to put out to sea again.
The decreasing num ber o f torpedoed Allied
ships was m ostly due to the de pletion o f raw
m aterials, the introduction o f convoys, the
application o f new techniques and Roger
Keyes’ anti-subm arine measures. In any case,
the example o f the Zeebrugge and Ostend
raids was follow ed in the Second World War.
On 28 March 1942 the British conducted
a successful raid on Saint-Nazaire. This
destroyed the dry dock o f the principal port
on the A tlantic coast and the only dry dock
large enough to repair battleships. From
then on, German w arships had to return to
Germany for repairs.
Nowadays, several m em orials, both in
Britain and in Belgium , remind us of the
operations that too k place in A pril and May
1918. In Zeebrugge, on the corner of Zeedijk
and Baron de Maerelaan, a m onum ent to
Saint George’s Day can s till be seen today.
The look o f the m onum ent has remained
unchanged since 1984. A plan o f Zeebrugge
harbour at the tim e o f the raid is flanked by
com m em orative plates for the blockships
and the subm arine. On Adm iraal Keyesplein,
also in Zeebrugge, a m em orial has been
erected w ith fragm ents o f the mole w ith
which HMS Vindictive collided du rin g the
landing o f troops.
And the bow o f HMS Vindictive as w ell as
the masts o f HMS Thetis and In tre p id were
located at Graaf de Smet de Naeyerlaan in
Ostend for m any years; now, after a recent
restoration, they are displayed near the
eastern pier o f the port o f Ostend.
Sources
• D e G r o o t B . ( 2 0 1 2 ) . V a n D u it s e B o c h t t o t S c a p a F lo w . D e
Top: the V indictive m em o ria l in O stend
has rece n tly been m oved (Tolhuis Provincial
Libraryj.
Bottom: the b o w o f HM S V indictive a t the
n e w lo ca tio n n e a r the Oosterstaketsel p ie r in
O stend d u rin g the solemn in a u g ura tio n on 2 4
M a y 2 0 1 3 (M a rn ix Pieters, Flanders H eritage
A g e n cyj
32
o o r lo g t e r z e e 1 9 1 4 -1 9 1 8 .
• D e s e y n e A . ( 2 0 0 7 ). D e k u s t b e z e t 1 9 1 4 -1 9 1 8 , B r u g g e .
• D e V o s L. ( 2 0 0 3 ) . D e E e r s te W e r e l d o o r l o g , L e u v e n .
• K a ra u M . ( 2 0 0 3 ) . W ie ld in g t h e D a g g e r. T h e M a r in e k o r p s
F la n d e r n a n d t h e G e r m a n W a r E f f o r t 1 9 1 4 - 1 9 1 8 , W e s t p o r t .
• P r in c e S . ( 2 0 1 0 ) . T h e b l o c k i n g o f Z e e b r u g g e . O p e r a t i o n Z - 0
1 9 1 8 , O x fo rd .
• R y h e u lJ . ( 2 0 1 0 ) . M a r i n e k o r p s F la n d e r n , E r e m b o d e g e m .
VLIZ
IDE GROTE REDE]
2 0 1 3 • 36