page_title: SF Hydro
section_title: Sinking
hierarchical_section_title: SF Hydro / Sinking
caption_attribution_description: English: Mæl railway station on Tinnosbanen, with DF Hydro at dock. Tinn, Norway.
context_page_description: SF Hydro was a Norwegian steam powered railway ferry that operated in the first half of the 20th century on Lake Tinn in Telemark. It connected with the Rjukan Line and Tinnoset Line, at Mæl and Tinnoset, operating between 1914 and 1944. The combined track and ferry service was primarily used to transport raw materials and fertilizer from Norsk Hydro's factory at Rjukan to the port in Skien. It was the target of a Norwegian operation on 20 February 1944, when resistance fighters sank the ferry in the deepest part of Lake Tinn in order to prevent Nazi Germany from receiving heavy water.
context_section_description: The German occupation of Norway (1940–1945) during World War II made Rjukanbanen the area for a crucial struggle between the Norwegian resistance movement and the Third Reich.  In February 1940, before the occupation, the entire Vestfjorddalen and the docks were closed to foreigners.  On 4 May 1940 German troops reached Rjukan, a month after the invasion of Norway had started.  The ferries were camouflaged and by January 1941 lack of coal resulted in the steamships being fired by wood.
  One of the byproducts at Rjukan was the production of heavy water—a key component in nuclear weapons, and necessary as a moderator in German nuclear designs. The hydrogen plant at Vemork was the first mass producer of heavy water, and in 1939 the German company IG Farben, owning 25% of the shares in Norsk Hydro, asked for permission to import five liters of heavy water into Germany, later denied due to a lack of an export licence.  In 1939–40 production at Vemork was 20 kilograms, by 1942 production had increased to five kilograms per day.
  The first attempt to halt the production from the resistance movement was Operation Grouse in October 1942, which failed when the Germans caught the plotters. As a consequence passenger transport after 7 April 1942 from Ingolfsland Station to Rjukan was only permitted for soldiers, police, workers at the plant and schoolchildren. All filled ammonia wagons were stored indoors in a tunnel under heavy guard. On 16 November 1943 the United States Army Air Forces bombed the hydrogen plant; the attack killed 21 civilians but failed to damage the heavy water plant as it was located under seven stories of reinforced concrete.
  The Germans decided to cancel production of heavy water at Rjukan and move the remainder of the potassium hydroxide— from which the heavy water was distilled – to Germany. The resistance movement was aware of this plan, and considered blowing up the train at various places, but instead chose to target the ferry SF Hydro.
  To minimize the civilian losses, Kjell Nielsen at Norsk Hydro delayed the tapping of the potassium hydroxide one day to allow the shipment to be carried on a Sunday. On Saturday 19 February 1944 the plant director Bjarne Nilssen informed the railway that a wagon with potassium hydroxide would be sent with train number three the following day departing from Rjukan at 8:55 and connecting with the ferry from Mæl at 9:45; the shipment would arrive at Tinnoset at 11:35. NSB car Lf4 no. 32628 was loaded with 39 barrels, of which five 70-kilogram (150 lb) barrels were to be unloaded at Notodden.  The wagons were set up at Rjukan on the Saturday, but failed a weight check, and part of the load was transferred to wagon L-84. The wagons were stored overnight with a single guard.
  That same evening two civilians, Jon Berg and Oskar Andersen, were guarding the Hydro.  The saboteurs Alf Larsen, Knut Lier-Hansen, Rolf Sørlie and Knut Haukelid waited a few kilometers from Mæl and broke into the ferry quay by cutting through a fence.  They entered the ship, but were discovered by one of the two guards; Lier-Hansen indicated that he was a worker and wanted to sleep on board, in the end convincing the guard. Sørlie and Haukelid went below deck to the keel where they spent two hours placing 8.4 kilograms (19 lb) of plastic explosive; they placed it in a circular formation 3.6 metres (12 ft) long.  The explosion would blow out one to two square meters (ten to twenty square feet) of the hull.  The saboteurs left the ship unseen; Larsen and Haukelid left for Sweden while Sørlie left for Hardangervidda.
  According to Anthony Cave Brown in Bodyguard of Lies, Haukelid concluded after a trial run that the explosives would be most effective if placed in the bow. If holed near the bow, the ship's screws and rudder would quickly be lifted out of the water, leaving the captain and crew without control. Haukelid also determined that "[t]he explosion had to be big enough to sink the ship, but not so severe as to cause casualties among the passengers and crew." He carried the bomb, made from eighteen pounds 
caption: Mæl Station and DF Hydro
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