The Effects of Seawater on the Durability of Planks in Withstanding Ram Attacks: Experimental Archaeology

The present paper constitutes the second phase of a three-phase research project and focuses on the experimental determination of the Modulus of Elasticity (MoE), a fundamental material property. It builds on a previous study published in 2024, which developed an analytical model for estimating the minimum velocity required for an ancient warship to inflict significant damage on an opposing vessel through ramming. The MoE, together with several other parameters, plays a critical role in determining the ability of hull planks to withstand the forces generated during such attacks. For wood, MoE is influenced by species, moisture content, and growth conditions. However, published MoE values are typically obtained under controlled moisture conditions and do not represent seawater-saturated wood, which is directly relevant to submerged ship planks. To address this gap, the MoE of cedar (Cedrus libani), fir (Abies alba), and pine (Pinus spp.), was experimentally determined using three-point bending tests after one week of immersion in East Mediterranean seawater. The resulting MoE values provide representative mechanical properties for the analytical model developed in this study. Incorporating the experimentally determined MoE values into the analytical model of one trireme ramming another yields an estimated minimum impact velocity range of about 1.0–1.2 m/s, required for a ram to cause a catastrophic fracture of a single seawater-soaked plank.