How Denmark-Norway challenged the world's greatest navy with tiny, expendable gunboats
During the Napoleonic Wars, Denmark-Norway faced the Royal Navy's overwhelming might by abandoning traditional warships for a fleet of over 200 small, maneuverable gunboats. Designed for shallow waters, these vessels turned the tide in coastal skirmishes, proving that even a maritime superpower could be harassed by a swarm of cheap, agile attackers.
The Gunboat War (1807–1814) emerged from the ashes of the Second Battle of Copenhagen. After the British seized or scuttled much of the Danish-Norwegian fleet to prevent it from falling to Napoleon, the government in Copenhagen needed a rapid, cost-effective defense. Under the strategic guidance of Commodore Steen Andersen Bille, they turned to gunboat warfare, utilizing designs by the Swede Fredrik Henrik af Chapman.
These gunboats were highly effective in still, shallow waters where large British warships struggled. The fleet included four distinct classes, ranging from the large Kanonchaluppen, armed with two 24-pounder cannons and four howitzers, to the smaller Morterbarkasserne, which were essentially ordinary boats fitted with a mortar. Despite their tactical advantages, these vessels were fragile; the mortar-armed barges, for instance, often leaked after firing only five to seven shells, requiring crews to return to harbor for repairs.
While the Royal Navy maintained overall control of Danish waters, the gunboats successfully seized cargo ships and captured several British vessels, such as the HMS Tickler and HMS Seagull. The conflict also saw significant amphibious actions, including the British capture of the island of Anholt in 1809 to restore its lighthouse. The war eventually concluded with the 1814 Treaty of Kiel, forced by a Swedish invasion of Holstein, which saw Denmark-Norway cede Heligoland and Norway.
The legacy of this conflict highlights the limitations of naval supremacy when faced with asymmetric tactics. Although the British regularly escorted merchant convoys through the Sound and Great Belt, the constant threat of gunboat swarms forced them to adapt their operations. This period remains a study in how a smaller power can leverage geography and specialized, inexpensive technology to challenge a materially superior adversary during a global struggle.
Source: Gunboat War
