180 mm apart where the planks lie straight and about 125 mm apart where the planks turn. At the bow, all of the planks taper to butt the stem. The stem is carved from a single curved oak log to form the cutwater and has one land for each plank. The inside of the stem is hollowed into a v shape so the inside of the rivets can be reached during construction or repair. Each of the crossbeams has a ledge cut about 25 mm wide and deep to take a removable section of decking. Sea chests were placed on top of the decking to use when rowing. Most likely on longer voyages sea chests were secured below decks to act as ballast when sailing. The centre section of the keel has little rocker and together with flat midships transverse section the hull shape is suited to medium to flat water sailing. When sailing downwind in strong winds and waves, directional control would be poor, so it is likely that some reefing system was used to reduce sail area. In such conditions the ship would take water aboard at an alarming rate if sailed at high speed. The method of fastening the planking to the frames above the waterline is by iron rivets in the form of iron nails driven from outside and then turned over a cinch plate on the inside. The lowest nine planks on each side of the keel up to the around the waterline are held to the frames by the archaic method of tying using withies. These nine bottom planks are also thinner than elsewhere being about 2.5 cm in thickness compared with a thickness of about 3 to 4 cm for the upper planks. The thinner bottom planks are formed with cleats projecting from their inner face to allow the planks and frames to be tied together using withies. The overall effect of this construction is to make the bottom of the ship lighter and more flexible. The 1893 'Viking' replica of the Gokstad ship reproduced this form of construction. The Viking's captain, Magnus Andersen, reported that the lightness and flexibility allowed the bottom to rise and fall up to 18 mm in heavy seas without leaking and the gunwale could twist up to 15 cm out of line. Speeds of around 10 or 11 knots were recorded. The ship was built to carry