He then founded the company A/S Ørnen in 1903 for whaling in Finnmark, Bear Island and Spitsbergen. Until then whales were brought ashore for processing but that would all change when he created the world's first floating factory for the processing of whales. This would be the greatest invention in whaling history but one that would have a great impact on whale populations which would be taken in ever greater numbers. He purchased the "Admiralen" in Oct 1904 for £3,750 and converted it to a floating factory ship by his shipyard Framnæs Mekaniske Værksted, in Sandefjord and equipped it with 8 new open boilers. It first saw service in the Greenland Sea off the coast of Spitsbergen for the 1904–05 season. Due to the large number of whaling vessels around Spitsbergen the season before, Christensen decided to send her to the Antarctic for 1905–06. She left Sandefjord on 21 October 1905 on her first trip to Antarctica as a factory ship, accompanied by her three catchers Hauken, Ørnen and Alex. She arrived in Port Stanley on 13 December 1905.