On the Towing of Box-shaped Floating Structure with Shallow Draft : Comparison Between Model and Full-scale Test

Abstract

One of the box-shaped floating structures of the Technological Research Association of Mega-Float has been towed about 700 km from Mizushima, Okayama prefecture to installation site Oppama, Kanagawa prefecture. Its dimension is 100 m in length, 20 m in breadth, and 2 m in depth with 0.5 m draft. The full-scale measurement of the strain along the center line on the upper-deck, towline tension and the motion of the floating unit have been done. The wave condition during towing was 2 m significant wave height at maximum. The transfer function of the wave bending moment has been compared with the theoretical calculation and the model experimental data. The dynamic towline tension in waves has also been measured and the extreme maxima distribution has been shown. The model experiment using scaled elastic stiffness has also been carried out to investigate the wave bending moment, towing force, motion of the floating unit in both head and following waves. The theoretical calculation using pressure distribution method agree well with the experimental results concerning wave bending moment.