The war of 1864 saw few skirmishes between the Danish and Prussian navies. The superiority of Danish seapower overawed the fledgling Preussian navy at this early stage in its history. As in the Three Years War, a key element of Denmark's war strategy was the blockade of Germany's Baltic sea ports, thereby disrupting German overseas trade and hindering Prussian naval operations in support the Preussian army.

The supreme commander of the Prussian army, General von Moltke, nevertheless insisted that the navy attempt to breach the blockade so as to reach Flensborg Fjord, where it could support the Prussian army in it's crossing to Als, and possibly to Funen.

Keen to appease Moltke, Prussia's naval chief, Prince Adalbert, ordered Captain Eduard Jachmann, commanding the Prussian naval forces in the Baltic, to attempt to break the blockade. If this proved impossible it was hoped that his attack would at least serve to harass the Danish ships and give his inexperienced crews valuable combat experience.

Jachmann had at his disposal the corvettes Arcona and Nymphe, the paddle steamer Loreley and a division of gunboats. A reconnaissance he conducted on March 16th revealed three Danish warships outside Swinemünde (present-day Swinouscie in Poland) which Jachmann decided to attack with his combined force the following day.

The Danish Squadron
The Danish warships which Jachmann had observed were the frigate Sjaelland together with the corvettes Hejmdal and Thor, which comprised the blockading squadron of Admiral van Dokum.

Unknown to Jachmann however, van Dokum had been reinforced the day after Jachmann´s reconnaissance by the screw ship of the line, Skjold, which had been delayed by bad weather from joining the blockading force earlier. The Danish squadron therefore enjoyed a considerable firepower advantage over the Prussian ships.

The forces ranged against each other on 17th March 1864 were as follows:

The Danish squadron:
The screw frigate Sjaelland, 42 - 30 pdr. cannon
The screw ship of the line Skjold, 58 - 30 pdr. cannon
The screw corvette Hejmdal, 14 - 30 pdr., 2 - 18 pdr. cannon
The screw corvette Thor, 12 - 30 pdr. cannon

The Prussian squadron:
The corvette Arcona, 6 - 68 pds., 20 - 36 pds. cannon
The corvette Nymphe, 10 - 36 pdr., 6 - 12 pds. cannon
The paddle steamer Loreley, 2 - 12 pds. cannon
The gunboat division, 6 gunboats, 6 or 12 cannon

The Prussian plan
Jachmann planned to attack the Danish squadron head on, to shorten the range, then steer his ships onto an easterly bearing to allow the Prussian broadsides to bear against them. Thereafter they would make a fighting withdrawal to Swinemünde covered by the gunboats.

Jachmann's limited objective - in effect no more than a raid on van Dokum's ships - suggests he had little confidence at the outset in being able to defeat the Danes in battle. Nevertheless, he did enjoy one small, but critical, advantage over the Danes - namely the superior speed of his own ships.

The battle
At 7.30 a.m. Jachmann, aboard the Arcona, and with the Nymphe astern, sortied from Swinemünde. Pursuing an easterly course he hoped to encounter the Danish warships observed the previous day. When he failed to locate them, he set course to the north-west confident that there was nothing to threaten his withdrawal.

Outside Thissow the Loreley and the gunboat division joined the squadron, and together they set course towards the envisaged position of van Dokum's squadron. Due to a misunderstanding however, the Prussian gunboats unexpectedly withdrew under cover of land.

Jachmann's movements had not gone unobserved. Aware of the Prussian approach, van Dokum ordered his ships to raise steam. Slowly, the ships of his squadron began to bear down on the enemy. At 2.50 p.m. the battle opened with the first shot being fired from the Arcona, but because of the distance it fell short. When the range reduced to around 1,500 metres, the Arcona and Sjaelland turned to starboard and opened fire with their port broadsides.

The Nymphe and the Loreley followed suit, and soon both squadrons were exchanging a lively fusillade. Outgunned, the Prussian ships continued their turning movement and began to steam full speed to the south-east to retire out of range from the Danish gunfire. It's remarkable how quickly the Danes wrested the iniative from the attacking Prussians, thereby decisively altering the course of the battle.

Van Dokum now ordered the Sjaelland to bring first her port and then starboard broadsides to bear, in the hope of inflicting damage to Jachmann's ships and hopefully disabling them, before they were out of range. His manoeuvres were not in vain. The Loreley suffered heavy damage and casualties from a direct hit, forcing her, along with the Prussian gunboats, to make for the safety of Peerd. The Nymphe also sustained a number of hits, the most serious of which damaged her funnel and steampipe, causing her to reduce speed for a while.

Unfortunately, the damage inflicted was insufficient to allow the Danes to catch up with her for desicive action. Periodic shots from the bow-chaser of the Sjaelland, and the stern guns of the corvettes, continued until around 4.45 p.m. when the action finally petered out. At 8 p.m. Jachmann's corvettes reached the safety by Swinemünde and the Danish pursuit ended. After-action subsequently estimated that the Prussians had fired over 250 shots during the course of the action.

The end
The Danes lost 3 dead and 19 wounded during the battle, and the Prussians 6 dead and 6 wounded. Each of the ships engaged received some damage, though none sufficient to put them out of action. The battle of Rugen - which the Germans now call the battle of Jasmund - was the only occasion during the war when a Prussian squadron sought a serious engagement with the Danish fleet.

The battle not only proved that in material terms, Prussia's puny naval forces were no match for the superior ships and firepower of the Danish fleet.

But also that in terms of the exercise of command, the Danish naval officers performance in the tactical handling of the battle was superior to that of the prussians. Breaking the Danish blockade was, Prince Adalbert realised, impossible without taking risks that threatened annihilation.

For the remainder of the war Prussia's Baltic squadron remained safely - and inert - in harbour. However Jachmann's willingness to take on the Danes earned him the appreciation of William I who subsequently promoted him to Rear-Admiral.

A more serious naval threat closed in on Denmark shortly after the battle of Rugen. For some time the Austrians had been in the process of assembling a squadron to help their Prussian allies. They at least had ships that were an even match for the Danes. On 9th May the two squadrons clashed off Helgoland, in the most celebrated naval action of the war, and this time the Danes faced an enemy that was not willing to withdraw without a protracted fight.