Cutwaters Before Rams: an experimental investigation into the origins and development of the waterline ram

Abstract

Students at Stevens Institute of Technology (Hoboken, NJ, USA) investigated the reasons for an elongated projection at the bow of Mediterranean galleys. Using a 1:20 base model adapted from the Trireme Trust's Olympias fitted with: 1) an elongated projection; and 2) a control bow similar to excavated merchant ships, tow-tank tests were carried out at various speeds. Hydrodynamic resistance and power were calculated for each bow type. Above speeds corresponding to 6 knots, the cutwater bow significantly attenuated the model's bow waves when compared to the control bow. These results were then compared to those of the ship with a ram-type bow from experiments conducted in 1985 at the National Technical University of Athens, which showed similar wave-attenuating characteristics.