Page 14 - Nicolaes Witsen & Shipbuilding in the Dutch Golden Age

Foreword
in the sixteenth century, was often applied to a small ship rather than a large one to lessen the financial risk posed by the new method.
If it is true that the shell-first method is difficult to apply to a large ship, the question n aturally arises of how ship- builders of antiquity made use of the method when build- ing very large ships; in those times, too, the h andling of very heavy parts of the many frames of a large ship must have required a rel atively large amount of rather difficult labor. It is not only regrettable that only a single descrip- tion of the building of a large ship in antiquity has sur- vived, but also frustr ating that the text contains a l acuna at the very spot where the method of constructing the hull was presumably described. The description concerns the large grain freighter with passenger accommodations, the Syracusia, a ship built and l aunched c. 2 50 bc for King Hiero II of Syracuse under the g eneral direction of the physicist Archimedes, a citizen of that city-state. The de- scription is from Athenaeus, an author from the third cen- tury ad who cites a certain Moschion as his source.16
The lacuna in the text is preceded by a description of the materials that were u sed in building thi s large ship and is followed by one of its launching, in whic h a new method devised by Archimedes was employed. In be- tween, so it seems, was the description of the way the hull was built. The remaining fragment of that description, although very short, nevertheless contains an impor tant indication about the sequenc e of some ph ases in the mode of construction. The extant fragment describes how the planking of the hull was covered in lead sheathing to protect it against the ravages of the shipworm, Teredo na- valis: “and each time part [of the planking] was completed it was always c overed by tilin g made of le ad for whic h three hundred workmen, not counting their helpers, were continually employed.”17
Before commenting on thi s passage, I must briefly describe the st andard method of mounting the protec - tive metal sheathing on the hull . The latter was fi rst built up at least to the w aterline before being sub sequently covered by fabric drenched in t ar, after whic h the pl at- ing was mounted with short nails of copper or bronze on the wooden hull.18 The treenails and bronze nails joining the planking to the fr ames were alre ady in their pl aces,
regardless of whether the hull had been built according to the shell-first or skeleton-first method. Once the wooden hull had been built, the difference did not matter.
But the difference was essential while the hull was still under construction. Each time a few str akes were added to the hull, as Athenaeus—or Moschion—appears to say, they had to be f astened to the preex isting frames prior to being covered by lead sheathing. Otherwise, to j oin the strakes to the frames by treenails, it would have been nec- essary to pierce the sheathing, which would have negated its protective function. Obviously there would be no need to pierce the protective sheathing after it was mounted if the strakes had been fastened to the fr ames earlier. One can conclude that this, in fact, must have been the case— i.e., that the frame-first method must have been used.
The reason for proc eeding with the pl anking and the sheathing bit by bit may well have been the poor ac ces- sibility of the space under the hull of this large ship once it had been pl anked up to the w aterline. The alternate mounting of a few str akes and a row of “tiles” of protec- tive lead sheathing solved the prob lem. That the method was mentioned as such in the text ma y indicate that it was uncommon, as the skeleton-first method (implied by the text) c ertainly was. We have no other indic ations of the use of this method of shipbuilding in antiquity . We may surmise now that although uncommon, it was not un- known; perhaps it had been dev ised by Archimedes. In any case, the Syracusia may have stood a s a prototype for the later Roman grain freighters, which may have also been built by the skeleton-first method.
We can conclude that Witsen and Van Yk together provide a pict ure of the di ssemination of the methods of skeleton-first and shel l-first methods of shipbuilding in late seventeenth-century Holland. The two methods still coexist there and elsewher e; furthermore, it appears that they have done so s ince the third c entury bc. In the course of time usage of the shell-first method, which was initially ubiquitous, has become rare, while the sk eleton- first method, used in the beginning only for building ex - ceptionally large ships, has become the prevalent one.
—André Wegener Sleeswyk
xii