 The much larger Danish fleet blockaded Prussia's main ports, trapping Jachmann's ships—"Arcona" and —in Swinemünde.On 17 March, Jachmann took his two ships and the armed paddle steamer out to challenge the Danish blockade force.In the ensuing Battle of Jasmund off the island of Rügen, Jachmann's squadron was defeated by the more powerful Danish squadron and forced to retreat.