A T 2-SE-A1 tanker model was tested in the T. T. R. I. Model basin in order to determine longitudinal bending moments in regular waves. The hull of model was made of wood and cut at five sections. Each block of hull was connected by steel girder. Bending moments at five sections were obtained by measuring the bending stress on steel girder at the sections by means of resistance wire strain gages. Hydrodynamical forces acting on each part of hull were also measured. Tests were made in regular head waves having heights of h / L = 1/50 and 1/30, and lengths of λ/ L =0.75, 1.00, 1.25 and 1.50.