## 5 Results  
### Anchorage Circle Radius  
The anchorage circle radius is related to anchorage safety and utilization. According to the data in Table 2, the anchorage circle radius model in Table 3 was calculated, and the results are shown in Figure 8.  
Figure 7: Diagram of simulation.  
1. The anchorage circle radius value was relatively small. Compared with models A/C/D/E, the value of model F, which involves no consideration of the safety impact of passing ships, was significantly smaller when the wind force was less than or equal to 7. Compared with models B/C/D/E, model G, in which the safety impact of passing ships was taken into consideration, showed a middle value. The values of H and B, which both had a wind force of greater than 7, were also relatively small. Model I, which was set with the consideration of the safety impact of passing ships, had a wind force of greater than 7 and a safety distance of twice the ship's width, suggested a greater value than model B with the difference of 5-15%.  
Figure 8: Schematic diagram of comparative analysis of the anchorage circle radius. **(a)** Schematic diagram of the anchorage circle radius of a 192 m general cargo ship. **(b)** Schematic diagram of the anchorage circle radius of a 225 m general cargo ship. **(c)** Schematic diagram of the anchorage circle radius of a 333 m general cargo ship.  
Additional factors were considered. Models F-G considered factors such as water depth, wind power, ship type, ship loading condition, and ship parameters comprehensively. Therefore, the models mentioned above reflected the engineering practice background well with more accuracy.
3. Models G and I fully considered the influence of the safety of ships passing through the anchorage with the safety distance set to improve the anchoring safety.
4. Models F-G featured safety and high anchorage utilization. The Chinese standard of the length of the outgoing chain is suitable for various extreme environments, and its standard length is the longest. Models F-G adopted the above Chinese standard, but resulted in a relatively small anchorage circle radius, which improved the utilization rate of the anchorage under the premise of ensuring safety.
5. In model B, a small slope coefficient was selected for the water depth variable and a large constant was obtained for the intercept. Model C selects a larger slope parameter for the water depth variable. Model B pays more attention to the influence of wind on the anchorage radius. However, model C better considered the influence of the bottom sediment griping force on the anchoring radius. From the perspective of anchoring safety, Model B is more conservative.  
In conclusion, the improved anchorage circle radius model in this study altered the rough phenomenon of the previous model. One the one hand, it fully considered the ship type, the distance from the anchor chain hole to the bow, the trim angle, the loading condition and other factors, but also considered the wind, special types of ships with hazardous items such as oil tankers and the influence of ships sailing in and out of the anchorage upon the safety distance of anchoring ships. On the other hand, the radii of the improved model in the four situations were all in keeping with the acceptable range, and are smaller than the previous model values in the table in most scenarios. Moreover, the model was in line with an engineering practice background. The application of the improved model for mooring area detection will improve scientific detection, the safety of anchoring ships and the utilization of anchorage.