Investigating the motions’ characteristics of a towed barge in extreme heading wave

A towed barge is one of the typical sea transportation systems that is basically composed of towing and towed ships connected to each other by a tow rope. During a towing operation exposed to rough sea condition, the risk of collision and breakage of a tow rope may be high and the consequences serious. This paper describes an experimental investigation of a towed barge’s motions in heading waves. The effects of various lengths and the configuration of tow ropes incorporated with various loading conditions of the towed barge have been taken into account. Here, three tow-rope lengths were used, namely 1L, 1.5L, and 2L; meanwhile, the two tow-rope configurations i.e., Straight-Tow (ST) and V-Tow (VT) models were applied and incorporated with 50% and 100% of the loading conditions of the towed barge. Regardless of the tow-rope models of ST and VT, the results revealed that the towed barge’s motion responses were generally proportional to the increase of the towline lengths and the towed barge’s loading conditions. It should be noted here that the VT model with 1L tow rope length in the full loaded condition has less RAO of her heave and pitch motions as compared to the other towing arrangements. Merely, this research investigation provides very useful guidance on a ship towing navigation in waves.