The designed controller is used to build up the model of ship course control system. The simulation results show that with or without disturb or random disturb, the ship course control system based on IGA-BP algorithms can lead to no overshoot of ship turning and quick following, which is better than the controlling result of BP algorithm.

It provides a method of fragmenting gain for ship turning adjuster which could apace and stably achieve turning adjustment just by simple and useful measures based on yawing degree.

The maximum irregularly varying stress is produced with the ship turning quickly to starboard side and equals—8 Kg/mm~2. (3)In order to establish a reasonable design standard on the strength of a ship propeller,it is very important to take into account the fatigue strength of the propeller.

Engine and rudder are needed to avoid the ship turning and drifting away from the FLNG.

Because of the influence of the hull, the stern propeller of a twin-screw vessel is working under condition of oblique flow, and the unsteady working condition of the blade of a propeller is created. In this paper a study of the influence of oblique flow on various aspects of the properties of a propeller is described. It has been found that the thruat coefficient and the torque coefficient of a propeller working under condition of oblique flow are increased. If the angle of oblique flow is large, it is necessary...

Because of the influence of the hull, the stern propeller of a twin-screw vessel is working under condition of oblique flow, and the unsteady working condition of the blade of a propeller is created. In this paper a study of the influence of oblique flow on various aspects of the properties of a propeller is described. It has been found that the thruat coefficient and the torque coefficient of a propeller working under condition of oblique flow are increased. If the angle of oblique flow is large, it is necessary to introduce a suitable correction in screw design, otherwise, the screw would work under overload condition. It would cause the main engine unable to rotate at the given revolution with developing full power, so the designed speed of ship may not be reached. The approximate formulas for this correction are suggested. In addition, it is found the propeller lias been experienced by a transverse force while working in oblique flow. This transverse force consists of two parts: a force acting in the plane passing through this axis of propeller and parallel to the plane of oblique flow; and an another force, which is perpendicular to the plane. The first part of this force is already known before; the another part is arising from a blade working under unsteady condition. This is the reason for some single-screw ships turning automatically, thus explained why some vessels automatically turn along certain direction. In this paper these approximate formulas for the calculation of the aforesaid transverse force are suggested, and may be applied to compute the magnitude and the direction of transverse force acting on a propeller.

In this paper an experimental study on the stresses in the blades of a propeller of tugboat is presented,covering the results of bollard test,self running test.service running test,and steering manoeuvres test.The main conclusions obtained are as follows: (1)The mean stress of a propeller blade is linearly proportional to the propellers torque Q,but there is no linear relation between the fluctuating stress and torque Q.Nor is there between and nv—product of propeller speed and ship speed. (2)The largest mean...

In this paper an experimental study on the stresses in the blades of a propeller of tugboat is presented,covering the results of bollard test,self running test.service running test,and steering manoeuvres test.The main conclusions obtained are as follows: (1)The mean stress of a propeller blade is linearly proportional to the propellers torque Q,but there is no linear relation between the fluctuating stress and torque Q.Nor is there between and nv—product of propeller speed and ship speed. (2)The largest mean stress will be found in the bollard state while the largest fluctuating sterss in the self running state.Their values are—5.84 kg/mm~2 and 4.66 kg/mm~2 respectively. The maximum irregularly varying stress is produced with the ship turning quickly to starboard side and equals—8 Kg/mm~2. (3)In order to establish a reasonable design standard on the strength of a ship propeller,it is very important to take into account the fatigue strength of the propeller.As for a propeller of a tugboat,it is necessary to calculate the fatigue strength in the self running state as well as the static strength in the bollard state.In the case of propellers of the GD type,the strength calculations of the blade on the 0.25 R and 0.4 R sections should be taken into censideration.

A mathematical model suitable for sail asisted ship is formulated. The effect of sail on control boundary and freely manoeuvrable range of the ship in wing is calculated and analysed. An approximate formula of controling sail for minimizing the tactical diameter of the ship turning in wind is derived by using the theory of optimal control. Turning ability of ship in wind is calculated. All these investigations indicate that the manoeuvrability of the ship with a sail in wind is better...

A mathematical model suitable for sail asisted ship is formulated. The effect of sail on control boundary and freely manoeuvrable range of the ship in wing is calculated and analysed. An approximate formula of controling sail for minimizing the tactical diameter of the ship turning in wind is derived by using the theory of optimal control. Turning ability of ship in wind is calculated. All these investigations indicate that the manoeuvrability of the ship with a sail in wind is better than that without one if the attack angle of the sail is appropriately adjusted and the position of thesail is properly arranged.