Page 185 - Nicolaes Witsen & Shipbuilding in the Dutch Golden Age

Figure 2.223. Plate XXVI. Ring bolt, hook bolt.
These details speak for themselves. It
ever, that the total amount of iron that Witsen gives for his 134-foot pinas (122,800 pounds) does not at all c omply with figures he supplies for the amount of iron needed for ships of various sizes. For a 1 36-foot ship he c alculates 77,000 pounds, for a 1 30-foot ship on ly 66,000 pou nds, which is about half of what the pinas has!
Van Yk supplies two formulas for the amount of iron in a ship (pp. 49, 50): for the n ails the length, breadth, and depth of a ship are multiplied, with one pound of nails for every six cubic feet; for the pinas the weight of the nails would come to8,420pounds (134 ×29 ×13 ÷6).Apart from the nails, there was other iron in the ship in the form of bolts, chain plates, rudder irons, “piecework” (i.e., all iron fittings weighing les s than one pou nd), and so on. For this category, known a s “coarse iron,” the formul a was half a pound for ever y cubic foot (so f or the pinas, 25,259 pounds). For a light vessel three quar ters of this weight was reckoned, and for a ship with an orlop dec k, five quarters.
So according to Van Yk, only 33,679 pounds of iron would go into a ship the s ize of the pin as, which in no way can be reconciled with Witsen’s statements. Yet Van Yk concludes: “But remember that the one m aster Ship- wright will build hi s ship w ith much more Iron, and so heavier than the other, and so no fi xed Rule can be given for this” (p. 50).
125. Anchors
(65 I 14) The Ship’s Anchors are these.
The Bower; which is used in heavy weather , when the Sheet Anchor is too light.
The Sheet anchor; which is used together with the Bower.
The Kedge; is brought ahead, and is used to k edge the ship, in a calm.
The Grapnel, is an anchor with four arms; with which the launch and the longboat are anchored.
. ..
(117 I 24) About Anchors in general; and first, their decree or order.
Take twice the thickness with calipers, and for the length of the shank take as many feet as this comes to in inches.
For instance, thick 6 inches, 6
2
12 feet,
Then take as many inches, as there are feet, w hich adds to 13 feet 1 inch, for the length of the shank. Take the thickness three times, for the weigh t of the an- chor, two zeros added to the outcome, assuming
For instance, thick 6 inches 6
3 1800
pounds for the weight. Beneath 1000 pounds, then tak e 2 inches, w here above one inch was taken. Below ve hundred pounds,
take the thickness three times for the length: for in- stance, thick 21⁄2 inches, comes to a length of 71⁄2 feet, as 21⁄2
3
71⁄2
Also take the length, and halve it, for instance, half 71⁄2, is 3 3⁄4 feet, and for every foot of the half, as 3 3⁄4
feet, 100 pounds, coming to 375 pounds for weigh t. Also take three double thicknesses for the length: for instance, thick 21⁄2 inches, comes to the length of 7 1⁄2 feet. Then take the length and halve it: as, half 71⁄2, is 33⁄4, every foot 100 pounds, comes to 375 pounds for the weight, as above.
. ..
(118 I 11) It is also done to tak e a thousand pounds of weight for every hundred feet of length of the Ship: or ten feet of length, one hundred pounds of weight. And to roughly estimate the thickness, w hen the length is known, as man y inches thickness are reck oned as there are feet in length, measured with a rope around.
The arms together are 1 1⁄2 feet shorter than the shank: when traced on the outside they mak e a seg- ment of a circle.
The crown wide two thirds.
The ukes or palms half as long as the inside face of the arms, and broad two thirds.
. ..
(117 II 24) All our anchors have two arms at least. I t is true, that it is possible to mak e anchors with one
is strange, how-
How Ships Are Built in Holland Today
124. Bolts and Nails
167