Hello,
The length of the hull and deck planking on French ship must be between 22 and 50 (french) feet either from 7.15 to 16.25 m. This is explained by the supply of ports, it is more of an observation than a rule: the planks are 10 to 13 inches (27 to 35 cm) wide which requires trees of big size to debit if we take into account the removal of the sapwood.
For the sake of economy, it operates the maximum usable length in the trees also available strakes have very varying lengths but still nearby the recited values. Near the hull ends, strakes are shorter because they are cut in wood twisted to adapt to the curvature of constraints; on the sides, they are the longest length available in the timber yard.
Typically, the plank lengths on the plans are indicative, you have the freedom to place your differences, you only have to stick to the lengths detailed above, but mainly to avoid having two successive scarph on the same frame at least four or five strakes above or below.
For Le Gros-ventre, indicative lengths are drawn on the plates No. 21, 22 and 25.
Regards,
Gérard Delacroix
(Message send in MP to Mau)