Templates for the uppermost parts of the frames, such as top timber moulds, are occasionally depicted (Figure 4a) but are not generally discussed in manuscripts.
The component templates for a frame have surmarks centered in the middle of their overlaps. Such surmarks transferred onto the timbers would provide reference points for the assembly of the complete frame in its proper shape (Figure 4b). On all the "marked" vessels other than La Belle, there is only one surmark on the bilge. This is consistent with all the documentary descriptions of Mediterranean moulding. Thus La Belle having surmarks both on the upper and lower parts of the bilge curve already distinguishes its design from Mediterranean moulding.
In Mediterranean moulding the drawing of the frame shapes begins by placing the templates on the framing timbers after the centerline timbers are shaped (Figure 49r). Once the templates are actually ready to be placed on the timbers, they have already been marked with several scales subdivided into increments. Without this additional data marked on them, the midship templates cannot be used to design a "boat-like" shape. Even when duplicated and evenly distributed along the keel at frame stations, at best, the result is only a "barge-like" shape. Figure 49b illustrates that straight lines would define the longitudinal relationship between such templates.
The use of templates gives the impression that in Mediterranean moulding the transverse sections play the primary role in the design of the hull shape. However, to be useful, these templates must be marked in a way that indicates how much they need to be shifted, relative to a common centerline and baseline, to progressively alter the transverse shape from one frame to the next. In other words, it is necessary to quantify how much the shape of each frame narrows and rises in such a way that will result in smooth longitudinal curvature. It is the series of increments marked on the templates that hold the "secret" to how hull curvature is defined within the Mediterranean moulding system of design. It is my belief that understanding the design concepts behind these increments and the development of their use is itself the "secret" or key to our understanding the evolution of the quantification of curvature in Western ship design.
Defining the parameters for the change in hull curvature at specific frame positions before and abaft the midship frame—at the tail frames—is a fundamental element in Mediterranean moulding. Since in traditional Mediterranean moulding the frame shapes for only a limited percentage of the hull length are predetermined, design marks and sequential location labels appear only on the frames between and including the tail frames. Archaeologically some or all of the predetermined frames in these hulls are also distinguished from the frames at the ends of the hull by having more elaborate and better-secured scarfs between the floor timbers and first futtocks. NEXT
© 2014 TARAS PEVNY