There is one anomaly: the upper endpoint of the upper surmark on VIA falls on the diagonal, but the rest of the mark is exactly at the angle of the after diagonals.
The surmarks define straight lines only in a cross-sectional view. In the two-dimensional space of a flat drawing, this view is dominated by the curved shapes of the frames that are transversely oriented across the width of the hull. In real three-dimensional space, there is no superposition of all the frame shapes in one flat plane, and when the same surmarks are joined along the length of the hull, it becomes evident that they actually delineate fair longitudinal curves (Figures 1, 8). A fair curve is a smooth curve without any unintentional bumps or hollows.
To illustrate this concept, as well as to help in the proper positioning of the frames, colored ribbon and then narrow wooden ribbands were secured along the surmarks during the reassembly of La Belle's timbers in the Conservation Research Lab at Texas A&M University. These ribbands were then photographed from various angles (Figure 16a–d). Only when viewed from the ends of the vessel, as in the cross-sectional view or body plan of a ship drawing, do these ribbands line up on diagonals (Figure 16a). Viewed from any other position, the ribbands appear not as straight lines but as smooth curves running the length of the vessel (Figure 16b–d). The view from above in Figure 16c shows how the lower ribband narrows along the length of the vessel and would appear in the plan view or breadth plan of a drawing (Figure 8). The view of the hull in Figure 16d, although somewhat obstructed by the conservation tank wall, shows how the lower ribband rises along the length of the after part of the vessel and would appear in the profile or sheer view of a drawing (Figure 8).
The longitudinal nature of the surmarks brings up the possibility that although the transversely oriented surmarked frames defined the shape of the hull during construction, the actual definition of hull curvature in the conceptual design stage was based on defining these longitudinal curves. But how was this done?
Insights from Documentary Sources
The above discussion, presenting the conclusion that every third of La Belle's frames was erected first and that the surmarks carved on these frames define diagonals, is written mostly from an archaeological point of view. Establishing which parts of the surviving hull the shipwrights predetermined is just one aspect of reconstructing a vessel's design. Discovering how the vessel's original architect or shipwright generated the measurements needed to achieve such predetermination is a more elusive aspect.
Progress in the archaeological study of ship design has depended to a great extent on insights gained from documentary evidence. NEXT
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