Mould and Filler Frames
The archaeological evidence indicates that only the shape of every third of La Belle's frames was determined during the design process prior to the start of construction. This is consistent with what is shown in comparative French drafts. For example, in the Toulon flute draft, all the floor timbers are depicted in the sheer view of the vessel's bottom (Figure 7). However, only every third frame before and every fourth frame abaft the midship frame are drawn in the sheer and body plans.
French treatises explain how developing only some of the frames in the design stage relates to the actual construction sequence of the vessel. The frames drawn-out in the plans are known as mould frames, couples de gabari(t) (Duhamel 1758:174; Ollivier 1736:118(1992:357)). Their shapes were determined prior to the assembly of the ship. They would be raised, whole or in parts, prior to the insertion of the frames in between. Mould frames help define the shape of the hull during construction, and in some discussions in nautical archaeology, such frames are referred to as "active" (Basch 1972:16). The frames inserted between the mould frames are known as filler frames and their shapes were derived from ribbands bent onto and secured to the mould frames (Duhamel 1758:174; Ollivier 1736:118 (1992:358)). These frames provide structural strength but do not contribute to defining the hull shape during construction and can thus be considered "passive."
Laying out frame shapes was a specialized skill that at the time only a limited number of individuals in a shipyard possessed. By first raising only some of the frames, the shipwrights could assure they had the desired hull shape before using the majority of the framing timber designated for the project. Compass timber for curved frame shapes was an expensive commodity that could not be wasted. Ribbands were used not only to secure the mould frames in their proper orientations but also as an aid to judging the smoothness or fairness of the hull curvature. Subsequently forming the frames to match a fair hull shape defined in three dimensions by the ribbands was a relatively straightforward task. By having the main ribbands placed along the curves indicated by the diagonal surmarks, the shipwrights had consistent points of reference for determining frame shapes and positioning the timbers. Cutting the correct bevels for the filler frames would be relatively easy because they could be measured directly from the ribbands. In addition, the fastenings would be inserted once the frame timbers were already beveled and raised in place. NEXT
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