Battle of Heligoland

9 May 1864, Off Heligoland, North Sea

Disputed; Danish tactical success, blockade lifted

Tegetthoff's two Austrian frigates, with three small Prussian ships trailing behind, met Suenson's Danish squadron off the British island of Heligoland. After two hours Schwarzenberg was on fire for the third time and Tegetthoff broke off into neutral waters. Denmark claimed a victory, but the Danish blockade of the German North Sea coast ended, and an armistice followed three days later.

Royal Danish Navy

3 ships, none lost

Ship	Type	Outcome
Niels Juel Suenson's flagship	Frigate	Damaged
Jylland Rudder hit	Frigate	Damaged
Hejmdal	Corvette	Survived

Prussia + Austria

5 ships, none lost

Prussian Navy

3 ships, none lost

Ship	Type	Outcome
Preussischer Adler Lagged behind	Dispatch vessel	Survived
Blitz	Gunboat	Survived
Basilisk	Gunboat	Survived

Austrian Navy

2 ships, none lost

Ship	Type	Outcome
Schwarzenberg Tegetthoff's flagship; set on fire three times	Frigate	Damaged
Radetzky	Frigate	Damaged

Map

Tegetthoff brings an Austrian squadron north Spring 1864
Danish squadron to the North Sea May 1864