# Motion Response of the Submersible Underwater Towed System as Cable Length Changes
## 5 Conclusions  
The article simulates and analyzes the motion response of a submersible underwater towed system during retracting and deploying cable maneuvers. It examines simple maneuvering motions with accelerated and circular rotational motions, as well as composite  
Figure 16: The motion response values of the traction system corresponding to different parameters when the submersible circular rotational motion and cable length are varied. (**a**) Rotational speed; (**b**) Buoyancy-to-gravity ratio of towed body; (**c**) Drag coefficient in \(x,y,z\) directions of towed body; (**d**) Added mass coefficient in \(x\), \(y\), \(z\) directions of towed body; (**e**) Buoyancy-to-gravity ratio of towed cable. maneuvering motions involving retracting and deploying cable maneuvers, using a cable dynamics computational tool. The towed body depth and towed cable tension history curves were obtained for the towed system in different maneuvering motions. The value of the change in kinematic response under composite maneuvering motion is calculated. The laws regarding the impact of varying rates of cable length change on the kinematic response during submersible maneuvering motions are outlined. To ensure wider applicability of the conclusions, the effects of different maneuvering and structural parameters on motion response are discussed. 1. At the end of the retraction maneuver and the deployment maneuver, rapid and substantial fluctuations in tension occur at the point where the towed cable connects to the submersible. 2. When performing retraction maneuvers or deployment maneuvers during submersible acceleration, the simultaneous end of submersible acceleration and towed cable length change is avoided by selecting a suitable rate of cable length change. This can effectively reduce the maximum tension of the towed cable. During the deployment maneuver, as the length of the towed cable rises, the speed of the cable change also increases from 0.8 m/s to 1.2 m/s. This results in an initial increase and subsequent minor drop in the maximum tension of the towed cable. The maximum tension value occurs at a speed of 1.0 m/s. This is because the acceleration of the submersible ends at the same time as the cable length change at the towed cable length change speed of 1.0 m/s. 3. When the cable deployment maneuver was performed during the circular rotational motion, the range of tension variation was reduced from 0.30 kN before the deployment to 0.02 kN after the deployment. The stability of the towed cable tension at the end of the deployment was significantly enhanced. During the cable deployment process, the faster the cable length change speed, the larger the towed body depth change amount. An increase in towed cable length increases the total mass and inertia of the system. Increased inertia of the system results in less sensitivity to external forces, leading to a reduction in the magnitude of tension variations. At the same time, a longer towed cable has a larger surface area in contact with the water column, the damping effect of the fluid is more significant, and the tension will gradually decay as it propagates. This is because energy is absorbed and dispersed during propagation, thus reducing tension fluctuations. 4. The maximum tension of the towed cable in the circular rotational motion occurs at the rate of change of the cable length of 1.2 m/s at different rates of change of the cable length, and the maximum tension values of the retraction and deployment of the cable are 1.66 kN and 2.39 kN. While the maximum tension is reached when the rate of change of cable length is at its maximum, the rise in maximum tension does not directly correspond to the increase in the rate of change of cable length. This is due to the fact that the variation of the towed cable tension during the submersible circular rotational motion shows an obvious long periodicity and the time of the maximum tension appearing at different rates of cable length change is not consistent.