Roald Amundsen was secretive about his real attentions with regards of the "Fram" expeditions, the only persons to know in advance were his brother, and the ship's commander, Lieutenant Thorvald Nilsen. Lieutenant Prestrud and one other of the crew, Hjalmar Fredrik Gjertsen (1885-1958), were trusted with the information on the eve of the "Fram"'s departure from Norway. The rest of the crew of 18 was only to know upon "Fram"'s stop-over at Madeira. During the winter stay at Framheim in Antarctica Prestrud, assisted by Hjalmar Johansen, made scientific observations.