Page 34 - Nicolaes Witsen & Shipbuilding in the Dutch Golden Age

Chapter 1
Figure 1.10. Grebber’s table of proportional formulas (p. 114). Specifications in feet and inches are shown for the major parts of ships ranging from 60 to 200 feet in length (although we have no indications that there were any ships longer than 180 feet in Holland in the seventeenth century).
(273 II 51) It is hard to determine the vertical balance of the ship, if it has been corrupted by a super vening weight: the center of gravity, as maintained by many, should be a little aft of the center of the ship.
(257 I 44 ) The center of gravity of a oating Ship [ . . . ] is a point in the middle, around w hich all parts are in balance, unchangeable. But having thoroughl y consulted Philosophy, although this does not make any di erencetopractice,thiswillapplyonlyaslongas the body is parallel to the horizon; but should it tilt, the center of gravity will also change; the lowest part after the shift, will be found the heaviest and the cen- ter of gravity will incline toward this; of w hich the reason will be clear to w hoever understands the con- stitution of the whole; but because such would not t here, I will refrain from further explanations.
Even so, in Witsen’s time model tank-testing experi- ments were alre ady being c arried out to determine the
ideal hull-shape, but they were directed more tow ard speed than stability. And there were no me ans to tr ans- late the outcomes of these experiments to full scale.23 The emphasis on testing for speed is seen in this remark:
(274 I 3) All shapes of ships have been tested by towing slices of wood through the water, to determine which would sail the best: the ones going fastest through the water by means of the pulleys, were though t to be the best sailors.
In chapter 18 Witsen presents explanations for a num- ber of issues, such as the shape and size of the sails and the proportions of the ship’s body, but they are ba sed on experience and h ave no theoretic al foundations. His remarks always come down to w arnings about the u n- pleasant consequences of extreme dev iations from the standard. An example:
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