Counter-Admiral Lorentz Fisker (5 October 1753 – 1 January 1819) was a Royal Dano-Norwegian Navy officer who charted the Skagerrak and Kattegat and served in the French Revolutionary and Napoleonic Wars.

In 1761 Lorentz had been on board the Grønland, captained by his father, on a voyage to the Mediterranean[2] whose main purpose was to deliver members of the Royal Danish Scientific Expedition to Arabia Felix (modern day Yemen) to Constantinople.

[2] In this position he came to take a major part in the inquiry into the Benzelsterna case [1][Note 5] In 1789 he was promoted to captain, and in the same year he married Charlotte Amalie Kofoed, daughter of the Director of the Post Office and of the Prison Service.

[2][4] Among some fifty miniature portraits by Thorvaldsen are drawings of his fellow passengers made during this voyage[5] Back in Danish waters, Fisker was on the Trindel Light commission[Note 7] and, on land, enquiring into sites for placements of signal telegraphs.

Within a year, with indefatigable hard work, he had a considerable number of gunboats and small armed vessels in service and in addition had improved harbour defences, and the coastal militia.

[1] On 27 April 1808, in the war against Sweden, he advanced with 24 gunboats towards Strömstad on the Swedish border, but at Furuholm met with strong resistance and had, after ninety minutes of battle, to retire.

The 1809 Anholt expedition came to nought, frustrated by late winter storms, and the 1810 attempt, led by Jørgen Conrad de Falsen, failed miserably.

Lorentz Fisker had personally laid the plans for the Norwegian brigs’ attack on a large British convoy in the Skagerrak in July 1810.