Model Test and Simulation on Astern Docking Operation Using a High Speed Vessel for a Logistic Hub

Abstract

Logistics hub project, i.e. transportation of marine operation workers from the base on the land to the offshore platform using a logistics hub, high Speed vessel and helicopters, was led by J-DeEP (Japan offshore Design and Engineering Platform) as the Japanese National project (2014~15). NMRI (National Maritime Research Institute) had joined this project and conducted both experimental and numerical analyses for the feasibility study of this concept. Model test and numerical simulation of the fast tug system, i.e. docking operation of the high speed vessel to the stern of the logistic hub using winches equipped each side of the hub and constant thrusts of the vessel, were conducted to survey the feasibility of this tug system. There are some assessment points in this system. One is tension acting on each tug lines. The other is development of the tension control system and confirmation of the effect acting on those lines. Through the experiment, snapping load acted on those lines were confirmed. Tension control algorithm was mounted in the winch control systems to reduce this load. As a result, decrease in standard deviation of the tension was confirmed. In addition to this, some simulation models were developed to simulate tension of the line and motion of the vessel and good coincidence was confirmed between experimental results and simulation ones at oblique wave conditions. Additional survey was conducted in order to understand effect of the amount of the constant thrust generated by the vessel for holding its orientation using these simulation models. Though the survey, the most suitable thrust range was specified considering maximum value of tension, tension balance and standard deviation of yaw.