Pages 233-247
The towing experiment in waves using two types of model of offshore structures such as barge and semi-submersible has been carried out in order to investigate the effect of the towline length, towing speed, types of the towed vessels, sea state and the tow motion on the towline tension. The comparison between the towline tension of the hawser and the bridle has been done and the statistic analysis of the dynamic towline tension has been made. The applicability of the Hermite moment model to the statistic distribution of the towline tension has been discussed. Furthermore, the effect of the towline tension on the motion of tug and tow has mainly been investigated. The forced oscillation test with the towline cable model in still water has also been carried out to clarify the dynamic towline tension during towing. The experimental results have been compared with the theoretical calculation such as Fylling's simplified analysis, lumped mass method and Shin's method using clipping-off model. It is concluded that the Shin's method agrees well with the experimental results even in the case of the strong non-linearrty like a snapping.
