German auxiliary cruiser Thor

Thor (HSK 4) was an auxiliary cruiser of the Nazi Germany's Kriegsmarine in World War II, intended for service as a commerce raider. Also known to the Kriegsmarine as Schiff 10; to the Royal Navy she was Raider E. She was named after the Germanic deity Thor.

Early history
Formerly a freighter named Santa Cruz, she was built by Deutsche Werft, Hamburg, (DWH) in 1938, and was owned and operated by the Oldenburg Portuguese Line (OPDR), Hamburg. In the winter of 1939–1940 she was requisitioned by the navy and converted to an auxilliary war ship by DWH. She was commissioned as the commerce raider Thor in March 1940.

First cruise
The Thor began its first combat cruise on 6 June 1940, under the command of Captain Otto Kähler. Thor spent 329 days at sea, and sank or captured twelve ships with a combined tonnage of.

The Thor stopped its first victim on 1 July, the 9290-ton Dutch freighter Kertosono. The Kertosono was carrying a cargo of petrol, timber, asphalt, and agricultural machinery. Captain Kähler decided to send the ship under a prize crew to Lorient, France, where she arrived safely twelve days later. At the time, Thor was disguised as a Yugoslavian freighter.

On 7 July Thor encountered the Delambre, a  British freighter. Thor fired several broadsides, the third of which hit the Delambre, stopping her dead in the water, after which the 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. The Bruges was scuttled, and her crew of 44 was taken aboard the Thor. On the 14th, Thor stopped another freighter carrying wheat; the British freighter Gracefield. The Gracefield was sunk by demolition charges.

On 16 July Thor attacked the British freighter Wendover without warning, as Wendover was seen to be armed. The Wendover was hit by several shells from Thor and set on fire. A boarding party set demolition charges which caused the Wendover to capsize, and it was then sunk with gunfire. 36 of the Wendover's crew of 40 survived: two crewmen including the radio operator were killed in the attack, and two more wounded crewmen died of their injuries while on board Thor.

The Dutch freighter Tela, en route to the UK, was intercepted on 17 July. Thor fired a shot across the bow of the Tela, which stopped without sending distress signals. The crew of 33 abandoned the ship and were taken aboard the Thor, and the Tela was sunk by demolition charges.

On 28 July, Thor encountered the British Armed Merchant Cruiser HMS Alcantara (F88), which was armed with eight 6-inch guns. Kähler turned away from the Alcantara, and tried to outrun her for three hours until he realized the Alcantara was faster than Thor. At that point Kwhler decided to turn and fight, hoping to inflict enough damage on Alcantara to allow the Thor to escape. Thor scored three early hits, one between the bridge and funnel, a second towards the aft of the Alcantara, and a third on the waterline which caused flooding in the engine room, forcing the Alcantara to reduce speed. Thor turned away from the Alcantara and received two hits from her 6" guns, killing three crew members. Instead of risking further combat, Thor made its escape under cover of a dense smoke screen.

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 25 August and then returned to Brazilian waters. Two weeks later, on Sept 8th, 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. The Kosmos would have been a highly valuable prize ship, but the fact that she was short of fuel, slow, and easily recognizable made keeping her as a prize unfeasible. Kähler ordered Kosmos to be sunk by gunfire.

On 8 October Thor caught the 8,715 ton British refrigeration ship Natia. Thor scored a direct hit, which set the Natia dead in the water, though she continued wireless transmissions. Thor hit Natia 7 or 8 more times with gunfire, and a torpedo that tore open her side, another 35 rounds were fired before she sank. 84 crewmembers of Natia's 85 were taken aboard Thor, bringing her 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,HMS Carnarvon Castle, a 20,062 ton ship armed with eight 6 in and two 3 inguns. Thor carried three of her four 15 cm guns aft, so Cpt Kähler decided to force the Carnarvon Castle into a stern chase. Thor's gunners found their target in the fourth salvo, after which Cpt Kähler changed course, turning the chase into a circular fight, in order to bring the entire weight of Thor's broadside to bear. Thor was in command of the engagement; her gunners registered more than 20 hits, forcing the Carnarvon Castle to turn and flee to Montevideo, Uruguay. Six of Carnarvon Castle 's crew had been killed, and 32 more were wounded.

Following this engagement, Thor was ordered to rendezvous with the German pocket battleship Admiral Scheer to transfer crewmen for prize crews for Pinguin's captured whaling fleet.

On 25 March Thor intercepted the SS Britannia (1925), an 8,800 ton British passenger ship. After scoring several hits on the fleeing ship, Kähler allowed her to be abandoned, before firing sixteen 15 cm rounds into the waterline, sinking the ship. German wireless operators intercepted a message from a nearby British warship approaching at full speed, from approximately one hundred miles away. Kähler decided to not risk an encounter with an enemy warship, and 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 approximately 520 surviors were ultimately rescued, primarily by the Spanish ships Cabo de Hornos, Raranga, and Bachi. 33 survivors eventually made landfall at Sao Luis, on the coast of Brazil, after 23 days and 1,500 miles adrift at sea.

On the same day, 25 March, Thor stopped the 5,045 ton Swedish motor vessel Trollenholm. Sweden was neutral in World War II, but Trollenholm was found to have chartered by the British to carry coal from Newcastle to Port Said. In less than 90 minutes, all 31 crewmen from Trollenholm 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 HMS Voltaire, a 13,245 ton ship armed with eight 6 in and three 3 in guns. Thor approached head on, and in response to Voltaire's signalling of a series of AAA's (an order to identify oneself), 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. Two of Voltaire's 6" guns continued to fire, though they only scored one hit on Thor, disabling her radio aerial. Thor's obsolete guns overheated and had to cease firing, at which point the Voltaire raised a white flag. Thor began rescuing the crew of the Voltaire, from a safe distance of 4,000 yards, to avoid damage from any secondary explosions. The captain of the Voltaire along with 196 men were rescued out of a crew of 296.

The last ship intercepted by Thor during her first cruise came on 16 April, on her way back to Germany; the Swedish ore carrier Sir Ernest Cassel. Two warning shots were fired, which stopped the ship; her crew was taken aboard the Thor, and she was sunk by demolition charges.

Second cruise
Thor set out on its second cruise on 30 November 1941 under the command of Captain Günther Gumprich. Thor sank or captured ten ships during her second cruise, for a total of 58,644 tons, during 328 days of operation.

On 13 March Thor was stopped by the British cruiser HMS Durban (I99). Thor identified herself as the British freighter Levernbank, which satisfied Durban, who went on her way. The following day Thor was again challenged, this time by the armed merchant cruiser Cheshire. Thor again identified herself as a British freighter, and was allowed to proceed.

Thor encountered its first victim on 23 March, the 3,490 ton Greek freighter Pagasitikos. Her crew of 33 was taken aboard Thor, and she was sunk by a torpedo. The next day, 24 March, Thor replenished its stocks from the supply ship Regensburg.

On 30 March Thor pursued the 4,470 ton British freighter Wellpark for seven hours. Cpt Gumprich sent his seaplane to strafe the freighter, but was driven off when the Thor opened fire on the Wellpark. Within 15 minutes, the 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 opening fire from the Thor. Following the plane's strafing run, Thor opened fire with her 15 cm guns, and set the oil drums on the Willesden's deck on fire, forcing the majority of the crew to abandon the ship; the only remaining crewmembers were the gunners, though they only managed to fire six shots before they were also forced to abandon the ship. Thor fired 128 shells into the Willesden, and finished her off with a torpedo.

Two days later on the 3rd, the Norwegian freighter Aust fell victim to the same tactics. She was unable to send a distress or raider signal before she was disabled and sunk by demolition charges.

Thor detected the 4,840 ton British freighter Kirkpool on his radar, the first installed on an armed merchant cruiser, on 10 April. Poor visibility and fog forced Cpt Gumprich to abandon his usual tactics and instead shadow the Kirkpool until nightfall. At close range, Thor attacked first with a torpedo and a salvo of her 15 cm guns, both of which missed. The second salvo scored three hits, and set the Kirkpool's bridge and wheelhouse alight. With the helm unattended, Kirkpool veered towards Thor, in what appeared to be an attempt to ram her attacker, which was avoided. Kirkpool's crew began abandoning the ship, and after a three hour search, 32 men were pulled from the water, including the Captain, Chief Engineer, and First Officer of the Kirkpool. The ship was finished off with a torpedo.

All of Thor's victims thus far were near the Cape of Good Hope, in the shipping lanes. The Kriegsmarine High Command (SKL) ordered Thor to move into the Indian Ocean, but was warned to be aware of Japanese submarines operating in the area.

On 10 May Thor's seaplane sighted the 7,130 ton Australian liner Nankin, en route to Bombay. From a distance of 13,000 yards, Thor opened fire with her 15 cm guns, scoring several hits. The Captain of the 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. The Nankin was renamed the Leuthen and taken as a prize ship to rendezvous with the Regensburg. Following resupply and prisoner transfer, the Leuthen and Regensburg both travelled to Japanese held ports.

On 14 June Thor's radar picked up a contact at 10,000 yards, and by using a converging course, was able to approach to within 1,800 yards, Thor attacked what turned out to be the 6,310 ton Dutch Shell tanker Olivia. The first salvo set the Olivia ablaze, killing most of the crew. The Third Officer, three other Dutchmen and eight Chinese were able to lower a single boat, but Thor was only able to locate one man in the water. These 12 men were adrift for a month before their boat capsized in the breakers off Madagascar; 1 Dutch and 7 Chinese sailors had died during the month at sea.

Five days later on the 19th, Thor intercepted the Norwegian oil tanker Herborg. Her seaplane disabled Herborg's radio aerial, and a warning salvo from Thor brought Herborg to a stop. The entire crew was taken aboard 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. The Madrono was halted in the same manner as Herborg, and a prize crew took her to Japan as well, renamed as Rossbach. The Rossbach was eventually torpedoed by the American submarine USS Burrfish (SS-312), in the Kii Channel, Japan, in May 1944.

Thor's tenth and final victim came on 20 July, 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 only fired 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 shell from Thor hit the bridge, killing him and knocking out the radio, and setting the bridge on fire. The Indus was now a raging inferno, and most of her crew went overboard. Thor ceased firing, and began rescue operations, picking up 49 survivors, before finishing Indus off.

Thor transferred her prisoners to the blockade runner Tannenfels, and made for Yokohama, Japan, by way of Batavia, Indonesia.

Fate
Thor arrived in Yokohama on 9 October 1942 where she commenced refitting in preparation for a third voyage. However on 30 November a series of explosions on the supply ship GERMAN TANKER 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 the Nankin/Leuthen and the Japanese freighter Unkai Maru. All four ships were destroyed in the fire, and twelve of Thor's crew were killed. Thor was wrecked beyond repair, and was abandoned. Her captain, Kapitän zur See Gumprich, later commanded the GERMAN AUXILIARY CRUISER Michel on her second raiding voyage, from which he did not return.

A number of survivors of the ship were sent to France on the blockade runner Doggerbank and perished when the ship was mistakenly sunk by the GS U-43 (1939) on 3 March 1943 with all but one of the 365 strong crew lost at sea.