The old builders of wooden vessels determined the ship’s length by the work for which it was intended. This length was measured from the forward side of the stem to the after side of the sternpost. The beam and the depth were deduced from the length; the beam being taken equal to one-fourth of the length, and for the depth, one foot was taken for each 10 feet of length, at the point where the vessel’s height was least. It was only for esthetic reasons that the sternpost was made higher than the stem. When the keel was laid down, the sternpost and the stem put up, the wing transom was made fast to the fashion timbers, then the main frame and the frame at the junction of the stem were reared. Another frame was raised between the main frame and the sternpost. “Centen” (thin flexible boards, called ribands in English) were then made fast to these frames so as to determine in this way the shape of the ship and to deduce therefrom the other frames. According to ~Van Yk~ (p. 77), these boards are not called “centen”, but “certen”, because the form of the vessel is fixed by means of these boards and made “certain”. Other authors pretend that the word comes from “Kanten” or “Kenten” from the word “bekendheid” (knowledge). The shape of the ship was thus determined by trial after having settled, in the first place, on the main frame and the length. The smaller the vessel, the more sheer it had and the more ribands were required exactly to determine its shape. On the other hand it was customary to give the ship some sheer (zeegte), that is: to make it higher at the ends than at the middle. This sheer was obtained, after setting the ribands, by means of sheerstrakes of which the fastening was begun at the lowest point of the height of the ship. These sheerstrakes rose forward at the rate of 1 inch for every 6 feet of length, and aft at the rate of 5 inches for every 6 feet. The wales which served to protect the ship were laid according to the sheerstrakes. The sheer in large vessels (spiegelschepen) was gradually reduced and the effort was made insensibly to build ships with a flat deck in imitation of England and later of America. The sheer still exists in boats for inland waters, like the “Tjalken”, “Poonen”, etc. Only one wale or bend is used for small vessels, the larger ones, such as the “Tjalken” and “Smakken” require three bends superposed. It is noticed, as a rule, that the bends became lighter in the XVIIIth century, just as did the sternpost and the stem. The engravings which show boats prior to 1500, show also several equidistant bends, and it was only at the end of the XVIth century that the single bends of later days are seen to appear. Moreover, it is certain that the improvement of the navigable highways was one of the causes of the lighter construction of ships.