Page 57 - Nicolaes Witsen & Shipbuilding in the Dutch Golden Age

the way of cargo and were cr ank and more vulnerable to breaking up when running aground.
The Depth
The depth was also calculated from the length: one tenth. As with the w idth, the shipbuilder c ould play with these proportions to infl uence the per formances of the ship . Thus it made a big diff erence whether the ship was built for corn or for wood; in the case of corn (which is relatively heavy), the depth would be reduc ed by one or two feet to avoid overloading the ship.
155 231⁄2 inches. 150 221⁄2 inches. 145 2 feet.
140 21 inches. 135 21 inches. 130 191⁄2 inches. 125 19 inches. 120 18 inches. 115 171⁄2 inches. 110 161⁄2 inches. 105 16 inches. 100 15 inches. 95 141⁄2 inches. 90 131⁄2 inches. 85 121⁄2 inches. 80 12 inches.
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Short keels are of one piece; long k eels of 2 pieces; the longest keels of 3 pieces.
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(72 I 37) With a keel of 3 pieces, one chooses the best and soundest timber for the middle section, and joins the other pieces to its ends, these scarfs are to over lap generously. The lower scarfs are always to point to the rear of the ship, and bolted well together with at- headed bolts, especially in large ships, the bolts being clinched on the inner side of th e keel, and the ends of the scarfs nailed too with large nails, according to the thickness of the scarfs. One holds such keels, made of 3 pieces, to be stronger than the ones made of two: because with such a keel of 3 pieces the scarfs are for- ward and aft, while in the middle, where the keel has to endure the most pressure from the main mast, it is free of scarfs; which is very good, and makes the ship strong; although the main step is usuall y set at the middle of the keel, the broadest part of the keel is still at one third of the length from forward.
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(148 II 54) As with QQ [fig. 2.3] at c and d showing how the Scarfs of the Keel are to be.
4. The thickness of the k eel, is 1⁄4 more than the thickness of the inner side of the stem, and the breadth 11⁄2 times the width of the stem, w hich is at the main frame at one third from the bow , where the ship is at its widest; forward and aft it will meet the dimensions of the stem and sternpost.
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(149 I 3) When making a keel, one takes one fourth of the thickness of the stem for its thickness, and broad it shall be one half broader than the stem: at the ends it shall become somewhat thinner to meet the thickness of the stems.
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(72 I 30) The breadth of the keels forward and aft of- ten varies, as the timber is peaked, and to adjust to the stem, always becoming thinner and narrower.
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(72 I 1)
(72 I 5) A Ship of 180 feet length over the stems, needs a k eel broad 2 1⁄2 feet in the middle, as man Shipbuilders will teach. W herefrom one can propor- tionally derive, that the k eel for 175 feet shall be 2 feet 41⁄2 inches broad in the middle.
For 170 2 feet 41⁄2 inches. 165 2 feet 21⁄2 inches.
160 24 inches.
Figure 2.2. Plate XXVIII. The keel. Left, heel (i.e., aft end of keel); right, boxing scarf (lit., “jawbone”)
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How Ships Are Built in Holland Today
(66 I 4)
First: One makes the keel. About the Keel.
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