Thor (HSK 4) was an auxiliary cruiser of Nazi Germany's Kriegsmarine in World War II, intended for service as a commerce raider.

[1] Thor spent 329 days at sea, and sank or captured 12 ships with a combined tonnage of 96,547 gross register tons (GRT).

At that point Kähler decided to turn and fight, hoping to inflict enough damage on Alcantara to allow Thor to escape.

Two weeks later, on Sept 8, the Yugoslav Federico Glavic was stopped, but allowed to proceed unmolested, as Yugoslavia was neutral at the time.

On 26 September Thor's float plane discovered the Norwegian whale-oil tanker Kosmos, which was carrying over 17,000 tons of whale oil.

Thor scored a direct hit, which stopped Natia dead in the water, though she continued wireless transmissions.

Thor carried three of her four 15 cm (5.91 in) guns aft, so Kähler decided to force Carnarvon Castle into a stern chase.

Thor was in command of the engagement; her gunners registered more than 20 hits, forcing Carnarvon Castle to turn and flee to Montevideo, Uruguay.

[2] After this engagement Thor was ordered to rendezvous with the German pocket battleship Admiral Scheer to transfer men for prize crews for Pinguin's captured whaling fleet.

After scoring several hits on the fleeing ship, Kähler allowed her to be abandoned, before firing 16 15 cm (5.91 in) rounds into her waterline, sinking her.

German wireless operators intercepted a message from a nearby British warship approaching at full speed from about 100 nmi (190 km; 120 mi) away.

Thirty-three survivors eventually reached land at Sao Luis, on the coast of Brazil, after 23 days and 1,500 nmi (2,800 km; 1,700 mi) adrift at sea.

[2]: 91 On her return trip to Germany, Thor encountered a third armed merchant cruiser off the Cape Verde islands.

Thor's first salvo hit Voltaire's generator and radio room, rendering her unable to transmit signals.

Two of Voltaire's six-inch guns continued to fire, but they scored only one hit on Thor, disabling her radio aerial.

Thor began rescuing Voltaire's crew from a safe distance of 4,000 yd (3,700 m) to avoid damage from any secondary explosions.

[1] The last ship intercepted by Thor on her first cruise was on 16 April, on her way back to Germany; the Swedish ore carrier Sir Ernest Cassel.

On 10 April Thor detected the 4,840-ton British freighter Kirkpool on her radar, the first installed on an armed merchant cruiser.

Poor visibility and fog forced Gumprich to abandon his usual tactics and instead shadow Kirkpool until nightfall.

The Kriegsmarine High Command (SKL) ordered Thor to move into the Indian Ocean, but warned her to be aware of Japanese submarines operating in the area.

She was carrying secret papers from the New Zealand "Combined Intelligence Centre" in Wellington to the C-in-C, Eastern Fleet in Colombo.

Thor transferred her prisoners to the blockade runner Tannenfels, and made for Yokohama, Japan, via Batavia in the Japanese-occupied Dutch East Indies.

On 30 November explosions on the supply ship Uckermark destroyed her superstructure, sending a large amount of burning debris onto Thor, which was moored alongside.

Her captain, Kapitän zur See Gumprich, later commanded the German auxiliary cruiser Michel on her second raiding voyage, from which he did not return.