A VecTwin rudder system comprises twin fishtail rudders with reaction fins to increase its performance. With a constant propeller revolution number, the vessel can execute special low-speed maneuvers like hover, crabbing, reverse, and rotation. Such low-speed maneuvers are termed dynamic positioning (DP), and a DP vessel should be fully/overly actuated with several thrusters. This article introduces a novel and experimental VecTwin positioning system (VTPS) without making the ship fully/overly actuated. Unlike the usual dynamic positioning system (DPS), the VTPS is developed for low-speed operations in a calm harbor area. It is designed upon the assumption that the forces due to the interaction between the rudders, the propeller, and the hull are linear with the rudder angles within a range around the hover rudder angle. The linear relationship is obtained through linear regression of the results from several CFD simulations. The VTPS implements a PID controller that regulates the actuator forces to achieve the given low-speed positioning objective. It was tested in combined automatic docking and position-keeping experiments where disturbances from the environment exist. It shows promising potential for a practical application but with further improvements.

VecTwin 舵系统由双鱼尾舵和反应鳍组成，以提高其性能。在螺旋桨转数恒定的情况下，船舶可以执行特殊的低速机动，如悬停、偏航、反向和旋转。这种低速机动称为动态定位（DP），DP 船应使用多个推进器完全/过度驱动。本文介绍了一种新颖的实验性 VecTwin 定位系统 (VTPS)，无需使船舶完全/过度驱动。与通常的动态定位系统 (DPS) 不同，VTPS 是为在平静的港区低速运行而开发的。其设计基于这样的假设：由于舵、螺旋桨和船体之间的相互作用而产生的力在悬停舵角附近的范围内与舵角呈线性关系。线性关系是通过对多个 CFD 模拟结果进行线性回归而获得的。VTPS 采用 PID 控制器来调节执行器力以实现给定的低速定位目标。它在存在环境干扰的自动对接和位置保持组合实验中进行了测试。它显示出实际应用的巨大潜力，但还需要进一步改进。