SS Great Eastern
She also had six masts (said to be named after the days of a week – Monday being the fore mast and Saturday the spanker mast), providing space for of sails (7 gaff and max. 9 (usually 4) square sails), rigged similar to a topsail schooner with a main gaff sail (fore-and-aft sail) on each mast, one "jib" on the fore mast and three square sails on masts no. 2 and no. 3 (Tuesday & Wednesday); for a time mast no. 4 was also fitted with three yards. In later years, some of the yards were removed. According to some sources she would have carried . This amount of canvas is obviously too much for seven fore-and-aft sails and max. 9 square sails. This (larger) figure of sail area lies only a few square metres below that the famous Flying P-Liner "Preußen" carried – with her five full-rigged masts of 30 square sails and a lot of stay sails. Setting sails turned out to be unusable at the same time as the paddles and screw were under steam, because the hot exhaust from the five (later four) funnels would set them on fire. Her maximum speed was 24 km/h (13 knots).
Wilhelm Zahn
Zahn was drawing from his U-boat experience and was aware of British anti-submarine tactics in the Atlantic which included a minimum cruising speed limit of 15 knots for British commercial vessels, necessary to safely outrun the U-boats, and proposed this to Petersen. Petersen however was mindful of the damage the ship had sustained in an aerial bombardment the year before and did not believe that subsequent repairs to the hull were completely effective and had doubts that the ship's hull had the structural integrity to withstand the stresses imposed by the speed proposed by Zahn. He therefore insisted that the ship's speed not exceed 12 knots.