Page 56 - Nicolaes Witsen & Shipbuilding in the Dutch Golden Age
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Chapter Two
measurement methods were used on ly for ship s already built.1
It was diffi cult, of course, to me asure over the stems if the ship was completely paneled and fi tted, and other points of measurement had to be fou nd. But for a ship being constructed, shipbuilders generally used the me a- surement over the stems, as few other points of measure- ment were available: tec hnically, it was easi est to tie a rope between stem and stern and measure that. Thus, the beakhead and the o verhanging counter and stern g allery were not counted with this method.
The length of the ship was taken as the main measure- ment for building a ship in Witsen’s time. In the arc hives ships are of ten indicated by leng th. But this was not al- ways so. At the beginning of the seventeenth c entury ships were referred to by their number of lasts, a measure of the ship’s cargo capacity and equal to appro ximately two tons (see “Ship Me asurement” in c hapter 1). As the client was generally interested only in the loading c apac- ity of the ship he had ordered, the length was determined by the shipbuilder . A s imilar method ba sed primarily on the vessel’s carrying capacity was used in the sixteenth century by the B asques, who me asured ships according to tonnelados (barrels of a standard measure): a ship of four hundred tonnelados, for instanc e, was c onstructed so that four hundred barrels could be fitted into it.2
It is unlikely that such an ex act correlation also pre- vailed in the Netherlands, but in the 1630s the practice of referring to ships according to number of lasts was aban- doned in f avor of giving their leng th in feet. Admir alty ships were usually referr ed to by their number of guns or their rate—we read about an eighteenth-century man-of- war of not 160 feet but 74 guns.3 Merchantmen, however, were measured in feet between the posts until well into the nineteenth century.
With the leng th established, the per formance of the ship in the Dutc h shoal waters was already largely de- termined: a ship too large was difficult to h andle and was liable to run aground due to its ens uing greater depth. Once grounded, it was of ten impossible to get afloat again. Small ships were popul ar but offered rel a- tively small cargo capacity, took in a lot of water over the sides, and c ould accommodate only small crews when many men were sometimes needed to defend the vessel against evildoers.
It is not clear wh at the averag e size of ships was in Witsen’s time. Witsen calls his 1 34-foot pinas a ship of average size. As mentioned in c hapter 1, ship s on Greb- ber’s list (fig. 1.11) range between 60 and 200 feet, but we have no indication that ships of 200 feet actually existed. In Van Yk’s work we find a contract from 1629 for a ship
of 172 feet, and Witsen mentions a ship of 180 feet, but elsewhere he states: The largest Rates for men-of-war ships used today, are long 175 feet between stem and stern, and wide 43 ft. (92 II 17). There is some allowance for commercial vessels, but the existence of ships larger than 180 feet seems unlikely for that period.
The Main Frame
The width (breadth) and depth (in the hold) was measured on the main frame, whic h was on a third of the leng th taken from the front of the stem. At this point the ship was at its widest . The width was measured ov er the frames, excluding the outside planking. Only where the real width was important, as with inland craft, which had to pass through locks and bridges and thus were held to a m axi- mum width, was the width measured overall.
The depth (also m easured at the main fr ame) was the distance between the upper side of the keel and the upper side of the lower deck beams, without including their cam- ber.4 The main point of reference in determining the size of many of the ship’s parts was the thickness of the inboard face of the stem, and this k ey dimension is the basis of almost half of Witsen’s shipbuilding formulas.5
Of course, not every shipbuilder used thi s particular reference point. Van Yk, for in stance, used it to a muc h lesser extent, and Witsen himself admits that there are other possible points of reference yielding approximately the same result. One can easily verify this with an example: the lower wales according to Witsen’s method should be of the s ame width as the inboard thic kness of the stem and half as thick. Van Yk, on the other h and, calculates the width of the wales by taking 12 inches for 100 feet of the ship’s length, for ever y 10 feet more leng th half an inch extra, and the thickness half of that. In the example of the pinas this comes to 131⁄2 inches, which is only slightly more than we would g et with Witsen’s method—131⁄4 inches. For more comparisons between Witsen’s and Van Yk’s formulas, see table 1 in the appendix.
The Width
The width of the ship i s derived from the leng th. Usually a quarter length was taken. But to a djust the design to its purpose, this rule was of ten adapted: a m an-of- war, which had to provide a stable platform for its guns, would be made wider , whereas fast ships would be slimmed down. The pinas, had it followed the rule, should h ave been 331⁄2 feet wide; yet it was only 29 feet wide.
Toowildadeviationfromtherulewouldof coursere- sult in difficulties: ships that were too wide were difficult to maneuver and would lurch wildly, sometimes resulting in broken masts, while n arrow ships could hold little in
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