1. 1 The Significance of Ship Maneuvering to Collision Avoidance Decisions xuan xiao dong

2. 2 ► First, the conduct and responsibility of collision avoidance in the Regulations are based on the relationship of two vessels. So it will be difficult to provide clear and definite instructions to the duty officer and the pilot to make collision avoidance decisions in multi-ship encounter situations.

3. 3 ► Second, the conduct in the Regulations is mostly based on the environment of broad waters, hence not suitable when the ship is going along the coast, narrow channels or reef island areas, where the behavior of collision avoidance is very limited.

4. 4 ► Third, an essential pre-condition for effective implementation of the Regulations is that the two vessels involved should fully understand and strictly obey the Regulations. However, that is highly unlikely in real navigational situations. Worse still, some officers of small vessels know nothing about the Regulations.

5. 5 ► Fourth, vessels are permitted to depart from the rules when necessary to avoid immediate danger, but it remains a question how to make such a departure and how to smooth out immediate danger. There is no answer in the Regulations.

6. 6 ► Fifth, the modification and perfection of the Regulations usually lag behind the development of navigational technology, such as ARPA, AIS, and VDR, providing more accurate information for making collision avoidance decisions and accident handling at sea; moreover, it will have some impact on the duty officer and the pilot for their behavior and habit in collision preventing. However, all the abovementioned continually fails to be found in the Regulations.

7. 7 ► The conception of ship maneuvering is a set of thinking patterns for making analysis, assessment, judgment formed by long-term practice and experiences summarization. the sense of space, the sense of space, the sense of time, the sense of time, the global viewpoint ， the global viewpoint ， the empathy viewpoint. the empathy viewpoint.

8. 8 The sense of space above water ► The sense of space above water is the conception of form and size of one’s own vessel and the encounter vessel above water for the officer and the pilot

9. 9 The sense of space under water ► The sense of space under water is related to ship’s draft and displacement. ► Many important factors can impact ship maneuvering such as navigable water area, current pressure and possible shallow water effect are all determined by draft. The establishment of such conception will remind us to consider the dangers underwater all the time and balancing all kinds of risks overall. ► Ship’s inertia and maneuverability owes much to its displacement, so such conception will help us to determine the “safe speed” and behaviors of collision avoidance by “reducing speed” or “altering the course”.

10. 10 the sense of time ► First, oftentimes, the sense of time has to do with the control of speed and correlates with the sense of space. When space remains constant, the faster the ship ’ s speed, the smaller a ship ’ s handler feels about the space. For ships with slow speed, the opposite is true. When forward situation is not clear, it is a bright “ conception of time ” to slow down for saving more time to make a better decision to avoid collision. ► Second, when the officer and the pilot encounter multi-ship encounter situations, it is important to give all the collision risks an overall consideration in order of priority according to the immediacy of each risk. ► Third, the factors which can impact ship maneuvering such as current regularity, traffic flow peculiarity and meteorology change, e.g. twilight, sunrise and sunset are all interconnected with the conception of time. With it, the officer and the pilot will be more confident and primed when making decisions to avoid collision.

11. 11 The global viewpoint The global viewpoint

12. 12 The global viewpoint ► In addition to collision, there are many other maneuvering risks in navigational practices, such as fairway depth, traffic flow, leeway, drift and heavy weather. ► We should be aware that collision avoidance is not the whole of navigation; it is only one of many methods to ensure the safety of navigation. Making collision avoidance decisions is a part of navigation safety and should take the whole situation on board.

13. 13 The global viewpoint ► When a vessel navigates in an area with big traffic flow, oftentimes the navigator will meet a lot of complex situations such as multi-ship encounter situation or continuous collision risk. ► Some collision avoidance behaviors are highly efficient and in conformity with the Regulations in the short-term; however, it will put vessels into another close-quarters situation and even into immediate danger later. It is necessary for us to have a ‘global picture’ to handle such complex situations; sometimes, a departure from the rules will be necessary for the whole situation.

14. 14 The empathy viewpoint ► When two vessels encounter, the final outcome is caused by the behavior of both sides. ► One side should not only consider its own behavior whether to follow the Regulations or whether it is appropriate for the prevailing circumstances and conditions, but also understand the other side ’ s background, thoughts, behaviors and psychology. ► Collision avoidance is like playing chess — the key to success is to know about both yourself and the other side.

15. 15 Conclusion ► One of the commonest misconceptions in the teaching and research of navigation is regarding the collision regulations as collision avoidance science. A lot of limitations of collision regulations are largely highlighted by this improper cognition. As the collision regulations are only a legal norm after all instead of a perfect theoretical and technical system, it is difficult for them to handle all the collision avoidance situations in real navigational work. ► Integrating ship ’ s maneuvering conceptions into collision avoidance decision can solve a lot of problems caused by limitations of the Regulations properly. And that may be one of the tendencies for the development of collision avoidance science in the future.

16. 16 Thank you very much for your attention! the end