Bending of Wooden Planks in Ancient Mediterranean Shipbuilding

摘要

The basic structural material for shipbuilding in antiquity was wood, which was easy to work and available in most civilizations. In order to install a wooden plank in a ship's hull it had to be bent and/or twisted to fit the curvature dictated by the shape of the hull. To reduce the force required for flexion without breaking the plank, it was necessary to soften it. The current research was aimed at finding the best method for bending Calabrian pine (Pinus brutia) planks, while ensuring minimal residual stresses and force, as well as having the minimum adverse effect on the mechanical properties of the wood.Experiments were conducted on seven groups of planks, including a control group, each group subjected to a different set of preparation methods. The results show that the residual stress in the planks assembled in the hull can reach more than 50% of the failure value. The method which affected the mechanical properties (modulus of elasticity and stress at fracture) the least was found to be direct open fire heating, but considering all the relevant parameters, appears that soaking and boiling in fresh water gives the best results overall.