Royal Danish Navy, 1914-1918
By Mike Bennighof, Ph.D.
During the first half of the 19th century,
the small kingdom of Denmark pursued an aggressive
policy at sea. A British sneak attack shattered
Danish naval power in 1801, and another attack
on Copenhagen finished off the fleet in 1807.
The Danes responded by planting 90,000 oak
trees toward the Navy’s rebirth, but
emerged from the Napoleonic Wars without a
navy or the ancient union with Norway. The Danish Nature Agency, successor to the royal forester, informed the Defense Ministry in 2007 that their trees were ready. Two of them were used in 2017 to build a replica Viking ship.
In 1848, the Danes responded to German
nationalist efforts to take the German-speaking
provinces of Schleswig and Holstein with vigorous
resistance. The navy played a major role in
the renewal of hostilities in 1850. Taking
the German threat very seriously, Denmark
was a leader in building first steam-powered
and then ironclad warships during the late
1850s and early 1860s.
Hostilities broke out again in 1864, and
the Danish fleet blockaded the German coastline.
When an Austrian squadron arrived in the North
Sea to break the blockade, the Danes and Austrians
fought off the island of Helgoland, then ruled
by Britain. Both sides claimed victory: the
Danes because they inflicted more damage on
the Austrians than they suffered themselves,
the Austrians because they forced the Danes
to lift the blockade. The Danes also fought
a drawn battle with the small Prussian fleet
off Swinemunde in the Baltic. In neither case
did the powerful Danish ironclads participate,
though the turret ship Rolf Krake proved
invaluable in keeping Prussian troops from
crossing the narrow “Little Belt”
strait between the mainland (Jutland) and
the Danish islands.
The cruiser Heimdal at Copenhagen.
Denmark eventually had to surrender the two
disputed provinces to the Austrians and Prussians,
and though the fleet received several more
ironclads after the war ended the kingdom
remained at peace for the next 50 years. While
some in the kingdom longed to recover at least
Schleswig and pointed to the plight of Danish-speaking
residents left on the wrong side of the border,
no sane Dane sought a war against the ever-growing
German Empire. The kingdom had flirted with
such a move in 1870, forging a tacit alliance
with France, but backed out of the operation
when the French marines promised for the Danish
front had to be flung into the struggle for
During the late 1880s the Danes began to
construct a series of armored coast defense
ships similar to those being built in Sweden.
Following Swedish practice, the Danes built
their ships domestically, laying them down
at Copenhagen Navy Yard and relying on Danish
naval engineers for their designs. This kept
the jobs generated within the Danish economy,
but led to extraordinarily long building times.
Danish mills could not supply high-grade armor
plate and the Danes spread their orders around
to maintain ties with all: The three heavy
ships launched between 1896 and 1903 had armor
supplied by English, French and German firms.
Most heavy guns came from Krupp in Germany.
Submarines came from Italy and Austria-Hungary.
Iver Hvitfeldt, launched in 1886,
was a very modern design for the time with
a pair of 10.2-inch guns in barbettes fore-and-aft.
She was rebuilt in 1904 with armored turrets.
The Danish construction program proceeded
very slowly, and a decade after Iver Hvitfeldt joined the fleet, the Navy laid down
a large coast defense monitor named Skjold bearing a single 9.4-inch gun. She was an
unusual design, with very low freeboard and
a large round turret forward; similar in appearance
to the small armored gunboats built in Sweden
but much larger.
Iver Hvitfeld after reconstruction.
The pace of Danish modernization began to
pick up, and in 1898 the Danes began construction
of the Herluf Trolle class of small
coastal battleships. These carried a pair
of 9.4-inch guns in single turrets fore and
aft, with four 5.9-inch guns in casemates
and a wide array of very light guns. Herluf
Trolle was launched in 1899, Olfert
Fischer in 1903 and the third ship of
the class, Peder Skram, in 1908. These
were small ships — 3,500 tons for the
first two, 3,700 tons for the third —
and all of very low speed but shallow draft.
Among the islands of the Danish archipelago,
they would provide heavy gunnery support to
the flotillas of small torpedo boats built
during the 1880's and replaced by more modern
types starting in 1907.
This doctrine was very popular in the years
before the Great War, and many nations fielded
a similar mix of forces. The Danes added submarines
to the strategy in 1909 with the Italian-built Dykkeren. In 1910 they ordered three
submarines from the Whitehead yard in Austria-Hungary,
and built three more to the same design in
Copenhagen. Five more were ordered in 1914
to a Danish design, giving the Danes the appearance
of a powerful undersea force for a small navy.
However, all the submarines were quite small
and of very limited range and performance.
Another coastal battleship, Niels Iuel, was laid down in September 1914. She was
only slightly larger than Peder Skram, but featured a modern mixed coal/oil power
plant like the newest German dreadnoughts
and a heavier armament of two 12-inch guns.
But her Krupp guns were seized for use by
the German army as railroad artillery, and
construction proceeded very slowly as Copenhagen
navy yard struggled to maintain the ships
on neutrality patrol. After the war the Allies
would not allow Krupp to fulfill the contract,
and the Danes instead bought ten 150mm (5.9-inch)
guns from Bofors in Sweden, mounting them
in shields. Launched in 1918, Niels Iuel was not completed until 1922.
Denmark also fielded several cruisers, to
show the flag in her Caribbean colony, the
Danish Virgin Islands. The small cruisers Heimdal and Gejser were no more
than gunboats, armed with two 4.7-inch guns
each. The much larger Valkyrien was
a protected cruiser carrying a pair of 8.2-inch
guns, and in 1915 she was sent to St. Thomas
as station ship, returning in early 1917 after
the islands were sold to the United States.
The coastal battleship Peder Skram, late in World War One.
Austria-Hungary declared war on Serbia on
28 July 1914, initiating a series of such
declarations as Europe exploded into open
war. The Danish fleet mobilized on 31 July
1914 under command of Vice Admiral O. J. Kofoed-Hansen.
Most of the navy’s major units had already
been fitted out for the annual summer maneuvers,
and they now would be assigned to enforce
The ships took up station in the three major
waterways linking the Baltic Sea and the North
Sea: “the Sound” between Sweden
and the island of Sjaelland (where Copenhagen
is located); the “Great Belt”
between Sjaelland and the island of Fyn, and
the “Little Belt” between Fyn
and Jutland (the Danish mainland). The Great
Belt and the Sound would have at least one
coast defense ship and one cruiser on duty,
supported by a flotilla of torpedo boats and
one or two submarines. The Little Belt, much
less useful for large ships, would be covered
by torpedo boats and obsolete ships.
When a Danish patrol found a German minelayer
dropping mines in the Great Belt on the morning
of 5 August 1914, the Germans demanded that
the Danes take over the task themselves. That
afternoon the Danish government issued a declaration
closing the straits and announcing that they
would be mined. Kofoed-Hansen then deployed
his forces to cover the minefields and prevent
The Danish action pleased the Germans greatly:
German ships could easily transit between
the North and Baltic seas via the Kiel Canal,
but British ships would now have a much more
difficult time entering the Baltic as would
Russian ships attempting to exit. Though Denmark
was officially neutral, this neutrality benefited
Germany and the “Baltic Project”
promoted by First Sea Lord Sir John Fisher
(a forcing of the Danish straits to land troops
on the coast north of Berlin) would have met
Danish resistance and thrown the kingdom actively
in to the Central Powers camp. Danish farmers
in particular enjoyed a “good war,”
as exports to Germany soared.
The Danes reported 164 violations of their
neutrality, the worst coming in August 1915
when the British submarine E15 grounded in the Sound
and a German torpedo boat attacked her in
Danish waters. The Germans ignored Danish
orders to retreat and shot up the stranded
sub, killing 15 of her crew. The German submarine
U20, which had torpedoed the liner Lusitania in May 1915, ran aground in Danish waters
in November 1916 and was a total loss though
no one was killed. The Danes lost one of their
own submarines in October 1916 when Dykkeren was rammed in the Sound by the Norwegian
freighter Vesla. Eight of her crew
escaped but her commander, Lt. Svend Aage
Christensen, died while helping them out of
the stricken boat. The wreck was salvaged
and broken up.
The Danes began sweeping their minefields
within hours of the Armistice ending the war,
causing their only surface ship loss of the
war when the torpedo boat Svaerdfisken ran on a German mine. Soon only Herluf
Trolle and Heimdal remained active,
as the Danes decided to trust in the new League
of Nations to prevent a new European war.
The submarine Dykkeren.
The Danish fleet appears in Great
War at Sea: Jutland with all of its
warships, though the scenarios featuring them
are strictly hypothetical. They are little
more than a speed bump in the way of the British
in the “Baltic Project” scenario,
and also get to fight in a number of other
“what if” engagements based on
actual war plans.
You can order Jutland right here.
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Mike Bennighof is president of Avalanche Press and holds a doctorate in history from Emory University. A Fulbright Scholar and NASA Journalist in Space finalist, he has published far too many books, games and articles on historical subjects.
He lives in Birmingham, Alabama with his wife, three children and his dog, Leopold.