Seakeeping Characteristics Of Two Ships Parallel Advancing For Underway Replenishment

In recent years,the ship supply problem has attracted the attention of many countries with the development of marine resources and shipping industry.Ship replenishment is important for the normal navigation of the ship,which can not only provide adequate logistical support for the ship,but also enhance the endurance of ship and reduce the dependence on the fixed base.Because of the characteristics of high efficiency and stability,parallel replenishment is the main way of supply.Due to the wave and hydrodynamic interaction between two ships parallel advancing in the ocean,the six-degree-of-freedom motions of them are more complex in doing replenishment.The close distance of two ship may cause violent hydrodynamic interaction and excessive distance will lead goods transmission failed,which makes great difficulties in replenishment.The seakeeping performance of two vessels is analyzed with AQWA,the main work is as follows:Firstly,we calculate the response amplitude operator of two parallel ships advancing in the ocean and single ship navigation.By comparing the theoretical analysis with the experimental results,the algorithm is proved reasonable.Secondly,by contrast two vessels' RAO with the single ship response in all wave directions,we study the effect of hydrodynamic interaction on seakeeping.Besides,the spectrum analysis and time response analysis are calculated in irregular waves.What's more,we compared the time domain results with frequency domain results by using the related function to verify each other.The relationship between seakeeping performance and transverse distance as well as speed is also discussed.As a result,the seakeeping of two parallel ships is effected by the hydrodynamic interaction,speed and transverse distance.Finally,we adopt a new method to study the effects of the cable between two ships to seakeeping,which converse the influence of cable to additional stiffness matrix.With comparison to the condition of ignoring the cable,we explore changes of seakeeping in different cable system and make a preliminary assessment for the rationality of the design of cable.