Experimental exploration of surf-riding in bi-chromatic following waves – results for the 1/64 scale ship model

Surf-riding is a dynamic phenomenon leading to broaching-to that may result in a collision or lead to a large angle of heel, possibly even capsizing. While the phenomenon of surf-riding in regular waves is well understood, the same cannot be said fully for irregular waves. This research conducted at Gdańsk University of Technology explores the phenomena that are intended to replicate cases presented in recent theoretical works. The paper includes a comparison of calculations and experimental results carried out mainly in a qualitative manner, though with an attempt to compare them quantitatively as well. First, the experiments run in a 40 m towing tank using a 1/64 scale ITTC A2 purse-seiner have confirmed the feasibility of reproducing surf-riding in monochromatic waves, even in such a short tank. Furthermore, the results obtained in this study for bi-chromatic following waves constitute the first experimental confirmation of a number of characteristic phenomena for the considered two-component irregular wave that contribute to the broader concept of surf-riding in irregular waves. • Comparison of simulation and experimental results in scope of surf-riding. • Experimental observation of surf-riding-related phenomena. • The ship can be attracted by either wave component in bi-chromatic following seas.