'Andalusien' was a German rendezvous position in the South Atlantic, between Trinidad and Tristan da Cunha, at which raiders and U-boats could meet their supply vessels (1940/42).

One of the most important such meetings took place in mid-November 1940 when the supply vessel Rio Grande met the 9,200-ton raider Thor for the transfer of weapons and other equipment required to extend Thor's operational endurance. Thor was also known to the German navy as HSK-4 and Schiff 10, and to the Royal Navy as Raider E. The ship was originally the freighter Santa Cruz, and in the winter of 1939/40 was requisitioned and converted into an auxiliary warship commissioned in March 1940 with the armament of six 150-mm (5.91-in) guns, two 37-mm anti-aircraft guns, four 20-mm cannon, four 21-in (533-mm) torpedo tubes and, for scouting, one Arado Ar 196 single-engined floatplane. The ship had a crew of 349, and her performance included a speed of 17 kt and range of 45,985 miles (74000 km).

The ship departed on her operational cruise on 6 June 1940, under the command of Kapitän Otto Kähler. Thor spent 328 days at sea, and sank or captured 12 ships totalling 96,547 tons.

Thor stopped her first victim on 1 July, this being the 9,290-ton Dutch freighter Kertosono, which was carrying a cargo of petrol, timber, asphalt, and agricultural machinery. Kähler decided to send the ship under a prize crew to Lorient, France, where she arrived safely 12 days later. At the time, Thor was disguised as a Yugoslav freighter. On 7 July Thor encountered the 7,030-ton British freighter Delambre, and fired several broadsides of which the third hit Delambre, stopping her dead in the water, after which Thor's boarding party scuttled the ship with demolition charges. Two days later Thor intercepted the Belgian freighter Bruges, which was carrying a cargo of wheat. Bruges was scuttled, and her crew of 44 was taken aboard Thor. On 14 July Thor stopped the British Gracefield, another freighter carrying wheat, and sank the vessel with demolition charges. On 16 July the British freighter Wendover was attacked without warning as she was seen to be armed, hit by several of Thor's shells and set on fire. A German party then boarded the ship and set demolition charges, which caused the Wendover to capsize but not to sink, so she was finally sunk by gunfire. The Belgian freighter Tela, on passage to the UK, was intercepted on 17 July. Thor fired a shot across the bow of the Belgian ship, which stopped without sending distress signals. The 33-man crew abandoned the ship and was taken aboard Thor after the Tela had been sunk by demolition charges.

On 28 July Thor encountered the British armed merchant cruiser Alcantara, which was armed with eight 6-in (152-mm) guns to Thor's six 150-mm (5.91-in) guns. Kähler turned his ship away from Alcantara, and tried to outrun her for three hours until he realised that Alcantara was the faster ship, at which point he decided to turn and fight, attempting to inflict enough damage to allow Thor to escape. The German raider scored three early hits, one between the bridge and funnel, a second toward Alcantara's after end, and a third on the waterline, which caused flooding in the engine room, forcing the British ship to reduce speed. Thor turned away from Alcantara and received two hits from her 6-in (152-mm) guns, which killed three members of the raider’s crew. Rather than risk further combat, Thor escaped under cover of a dense smokescreen. Following the battle with Alcantara, Thor made repairs to battle damage, cleaned her boilers, and changed her disguise.

Thor rendezvoused with the supply ship Rekum on August 25 and then returned to the waters off Brazil. Two weeks later, on 8 September, she stopped the Yugoslav Federico Glavic but then allowed her to proceed unmolested as Yugoslavia was neutral at the time. On 26 September Thor's Ar 196 floatplane discovered the Norwegian tanker Kosmos, which was carrying more than 17,000 tons of whale oil. Kosmos would have been an invaluable prize ship, but the fact that she was short of fuel, slow, and easily recognisable decided Kähler to sink her with gunfire.

On 8 October Thor caught the 8,715-ton British refrigerated freighter Natia. Thor scored a direct hit, which halted the British ship though she continued radio transmissions. Thor then hit Natia with another seven or eight shells, and also with a torpedo that tore open her side, but had to fire another 35 rounds before Natia sank; 84 members of the British ship’s crew were taken on board Thor, bringing her prisoner total to 368. Most of these prisoners were transferred to the supply ship Rio Grande in mid-November.

On 5 December Thor encountered another armed merchant cruiser, 'e]Carnarvon Castle, a 20,122-ton ship armed with eight 6-in (152-mm) and two 3-in (76-mm) guns. Thor carried three of her four 150-mm (5.91-in) guns aft, so Kähler decided to draw Carnarvon Castle into a stern chase. Thor's gunners started to hit their target with their fourth salvo, after which Kähler changed course, turning the chase into a circular fight in order to bring the entire weight of Thor's broadside to bear. The German gunners registered more than 20 hits, forcing Carnarvon Castle to turn and head for Montevideo in neutral Uruguay.

Following this engagement, Thor was ordered to rendezvous with the 'pocket battleship' Admiral Scheer to transfer men as prize crews for the Norwegian whaling fleet (11 catchers and three factory ships) taken by another German raider, Pinguin.

On 25 March Thor intercepted Britannia, an 8,800-ton British passenger ship. After scoring several hits on the fleeing ship, Kähler allowed her to be abandoned, before firing 16 150-mm (5.91-in) shells into the waterline, sinking the ship. German radio operators intercepted a message from a nearby British warship approaching at full speed from a distance of about 100 miles (160 km), and Kähler decided to not risk an encounter with a warship, but reasoned that the British ship would arrive and provide assistance to those in the water. Unfortunately, the British warship failed to locate the survivors: 331 out of about 520 persons were ultimately rescued, primarily by the Spanish ships Cabo de Hornos, Raranga and Bachi, and 33 others eventually made landfall at São Luis, on the coast of Brazil, after 23 days and 1,500 miles (2400 km) adrift. On the same day, 25 March, Thor stopped the 5,045 ton Swedish and therefore neutral vessel Trolleholm. Despite this, in less than 90 minutes all 31 members of her crew were transferred to Thor, and the freighter was sunk by demolition charges.

On her return trip to Germany, Thor encountered a third armed merchant cruiser off the Cape Verde islands. This was Voltaire, a 13,245-ton British ship armed with eight 6-in (152-mm) and three 3-in (76-mm) guns. Thor approached head on, and in response to Voltaire's signals ordering the ship to identify herself, fired a shot across Voltaire's bow. Thor's first salvo hit Voltaire's generator and radio room, rendering her unable to transmit any further signals. Voltaire was turned into a blazing inferno, but two of the British ship’s 6-in (152-mm) guns continued to fire, though they only scored one hit on Thor, disabling her radio antenna. Thor's old guns overheated and had to cease firing, at which point Voltaire raised a white flag. Thor began rescuing the Voltaire's crew from a safe distance of 4,000 yards (6400 m) to reduce the chance of taking damage from any secondary explosions. Of the Voltaire's crew of 296, 197 were rescued.

The last ship intercepted by Thor during her first cruise came on 16 April when, on her way back to Germany, she intercepted the Swedish ore carrier Sir Ernest Cassel. Two warning shots were sufficient to stop the ship, whose crew was taken aboard Thor before she was sunk by demolition charges.

Thor departed on her second cruise on 30 November 1941 under the command of Kapitän Günther Gumprich. During her second cruise, Thor sank or captured 10 ships (58,644 tons) during 328 days of operation.

On 13 March 1942 Thor was stopped by the British light cruiser Durban, but identified herself as the British freighter Levernbank and, satisfied, Durban went on her way. On the following day Thor was again challenged, this time by the armed merchant cruiser Cheshire, but was again permitted to proceed after identifying herself as a British freighter.

On 23 March Thor encountered her first victim of this second cruise in the form of the 3,490-ton Greek freighter Pagasitikos. Her crew of 33 was taken aboard the raider, and she was then sunk by a torpedo. On the following day, 24 March, Thor replenished her stocks from the supply ship Regensburg. On 30 March Thor pursued the 4,470-ton British freighter Wellpark for seven hours. Gumprich sent his seaplane to strafe the freighter, but the floatplane abandoned this task after Thor opened fire on Wellpark. Within 15 minutes, Wellpark's crew abandoned ship, and she was sunk.

On 1 April Thor intercepted another British freighter, the 4,565-ton Willesden. Gumprich again ordered his floatplane to destroy the vessel’s radio aerial before he opened with the ship’s guns. Following the floatplane’s strafing run, Thor opened fire with her 150-mm (5.91-in) guns, and set on fire the oil drums on Willesden's deck and persuading most of the crew to abandon ship; the only men remaining on board were the gunners, who managed to fire only six shots before they were also forced to abandon the ship. Thor fired 128 shells into Willesden, and finished her with a torpedo.

Two days later, on 3 April, the Norwegian freighter Aust fell victim to the same tactic. She was unable to send a distress or raider signal before she was disabled and sunk by demolition charges. On 10 April Thor detected the 4,840-ton British freighter Kirkpool on 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. At close range, Thor attacked first with a torpedo and a salvo from her 150-mm (5.91-in) guns, both of which missed. The second salvo scored three hits, and set Kirkpool's bridge and wheelhouse alight. With the helm unattended, Kirkpool veered toward Thor in what appeared to be an attempt to ram her attacker, but Thor avoided the oncoming British vessel. Kirkpool's crew began to abandon ship, and after a three-hour search, 32 men were pulled from the water. The ship was finished with a torpedo.

All of Thor's victims up to this time had been caught in the shipping lanes near the Cape of Good Hope. The German naval high command now ordered Thor to move into the Indian Ocean, but warned Gumprich to be aware of Japanese submarines operating in the area. On 10 May Thor's seaplane sighted the 7,130-ton Australian liner Nankin on passage to Bombay. At a range of 13,125 yards (12000 m), Thor opened fire with her 150-mm (5.91-in) guns, scoring several hits. The captain of Nankin issued the order to abandon ship and lowered his flags. The crew attempted to scuttle the ship, but the German boarding party managed to repair the damage done to the ship’s engines. Nankin was renamed Leuthen and taken as a prize ship to rendezvous with Regensburg.

Following resupply and prisoner transfer, Leuthen and Regensburg both travelled to Japanese-held ports. On 14 June Thor's radar found a contact at 10,000 yards (9150 m), and was able to approach to within 1,800 yards (1650 m) before opening fire on the 6,310-ton Dutch Shell tanker Olivia. The first salvo set the tanker ablaze, killing most of the crew. Twelve men were able to lower a single boat, but Thor was able to locate only one man in the water. These 12 men were adrift for a month before their boat capsized in the breakers off Madagascar: one Dutch and seven Chinese sailors had died during the month at sea.

Five days later, on 19 June, Thor intercepted the 7,892-ton Norwegian oil tanker Herborg. Her seaplane disabled Herborg's radio aerial, and a warning salvo from Thor halted the Norwegian. The whole crew was taken on board Thor, and a prize crew took the renamed Hohenfriedburg to Japan. On 4 July Thor stopped another Norwegian oil tanker, the 5,895-ton Madrono, which was halted in the same manner as Herborg, and a prize crew took her to Japan as well, renamed as Rossbach. Rossbach was eventually torpedoed by the US submarine Burrfish in the Kii Channel, Japan, during May 1944.

Thor's tenth and final victim came on 20 July in the form of the British refrigerated freighter Indus. Indus was determined to put up a fight, and turned away at full speed, firing with her stern gun, though she got off only two shots before a shell from Thor hit the gun directly, killing the chief gunner and destroying the gun. The freighter’s radio operator kept up a steady stream of distress signals, until another of Thor's shells hit the bridge, killing him and knocking out the radio, and setting the bridge on fire. Indus was now an inferno, and most of her crew went overboard. Thor ceased fire and rescued 49 survivors before finishing Indus.

Thor transferred her prisoners to the blockade runner Tannenfels, made for Yokohama in Japan by way of Batavia in the Japanese-occupied Dutch East Indies, and reached Yokohama on 9 October to start refitting in preparation for a third voyage. On 30 November, however, a series of explosions on the supply ship Uckermark destroyed her superstructure, sending a large amount of burning debris onto Thor, which was moored alongside. Both ships were rapidly set ablaze, along with Leuthen (ex-Nankin) and the Japanese freighter Unkai Maru. All four ships were destroyed in the fire, and 12 of Thor's crew were killed. Wrecked beyond repair, Thor was abandoned.