Thor conducted hydrographical and oceanographical research in the North Atlantic and the Mediterranean and helped locate the spawning grounds of the Icelandic cod.

[2] Most importantly, Thor conducted two expeditions to the Mediterranean Sea in 1908–1910 with Johannes Schmidt as cruise leader.

The aim of the expeditions, funded by the Carlsberg Foundation, was to locate the spawning grounds of the European eel.

In a broader perspective, the greatest result of the two expeditions was the very large contribution to the general understanding of the oceanography and pelagic fauna of the Mediterranean.

[2] In 1914, Thor was commissioned into the Royal Danish Navy, in which she remained until decommissioned in 1920 [1] and sold to Iceland.