Sailed4seas的部落格

Ex 04-03

Ownship speed is 18.6 Knots and course is 063.8 degrees at beginning. ​

The situational awareness is:

• With three minutes vector length in 18.6 Knots, this vector is about 9 cables distance as above. (skill by knowing  three minutes run)
• Ownship have two crossing vessel at starboard side (red circle), distance unknown. (sighted)
• One overtaken vessel at starboard side has same speed as ownship. (skill by comparing vector length)
• Ownship have three crossing vessel at port side (yellow circle), distance unknown. (sighted)
• One overtaken vessel at port side slower than ownship. (skill by comparing vector length)

The situational awareness with 6 minutes speed vector is:

• One port side crossing vessel will be at ownship bow after three minutes. ( skill by observing target vessel speed vector touched our heading at three minutes (yellow square))
• One starboard side crossing vessel will be at ownship bow after 4 minutes. ( skill by observing target vessel speed vector touched our heading at 4 minutes)

The situational awareness with 9 minutes speed vector is:

• Ownship have one collision point with crossing vessel at starboard side (Red Square), after 7.5 minutes or so. (sighted)
• Another crossing starboard side vessel has no collision risk as 9 minutes speed vector has no collision point. (sighted)
• One crossing vessel at port side will be at ownship bow after 7.0 minutes or so (Pink Square). (sighted)

Overall situation awareness is:

• Ownship have to take care of three vessels around but no collision risk right now.(action)
• Ownship has to give way (avoid arriving red square area at same time with target vessel)  if starboard crossing vessel keeps current speed and course.(action)
• Does Port side crossing vessel keep his course after crossed separation line? (suspect)
• Forget other slower vessels, it is no harm can be done.(suspect)

After 01minutes exercise time lapsed:

Ownship speed is 18.0 knots which had reduced from 18.6 kts with engine output reduced a little at beginning.

Ownship course is altered to port side 11 degrees to 052.2 from 063.8 degrees with rudder angle “Hard Port” used 20 seconds.

The situational awareness is:

• Once again, ownship headed into danger with no speed reduction. (suspect)
• Port side crossing vessel is at ownship bow now. (sighted)
• One overtaking vessel at starboard side is about same course with ownship. (sighted)
• Ownship can pass crossing vessel at starboard side after 6 minutes. (skill by using 6 minutes vector)
• One overtaken vessel at port side is still slower than ownship. (skill by comparing vector length)
• One crossing vessel at port side will pass ownship bow after 3 minutes. (skill by estimating speed vector direction)

After 02 minutes exercise time lapsed:

Ownship speed is 20.7 knots which had increased from 18.0 kts with engine output 100% after one minute.

Ownship course is steady in 052.2 for one minute from 063.8 degrees with rudder angle “Hard starboard” now.

The situational awareness is:

• Once again, ownship headed into danger with increased speed. (against all rules)
• Port side crossing vessel is passed. (sighted)
• One overtaking vessel at starboard side is far away now. (sighted)
• Ownship can pass crossing vessel at starboard side after 4 minutes. (skill by estimating 3 minutes vector)
• One overtaken vessel at port side is still slower than ownship. (skill by comparing vector length)
• One crossing vessel at port side will pass ownship bow after 2 minutes. (skill by estimating speed vector direction)

After 03 minutes exercise time lapsed:

Ownship speed is 18.3 knots again reduced from 20.7, 18.0 kts with engine output 50% after two minute.

Ownship course is altered 21 degrees to starboard side to 073.2 degrees from one minute before 052.2, and three minutes before 063.8 degrees with rudder angle “Hard starboard” and “”Hard Port”.

The situational awareness is:

• Once again, ownship straight out of danger with decreased speed. (compiling all rules)
• Course change suddenly to 073.2 degrees from one minute before 052.2 degrees.(sighted)
• Port side crossing vessel is passed. (sighted)
• One overtaking vessel at starboard side is altered course to port side. (sighted)
• Ownship has collision risk with crossing vessel at starboard side after 3.5 minutes. (skill by estimating 3 minutes vector)
• What to do with this collision risk? (suspect)
• One overtaken vessel at port side is still slower than ownship. (skill by comparing vector length)

After 04 minutes exercise time lapsed:

Ownship speed is 16.6 knots again reduced from 18.3, 20.7, 18.0 kts with engine output 50% after two minute.

Ownship course is altered 6 degrees to port side from 073.2 to 067.1 degrees from one minute before. using rudder angle “Hard starboard” and “”Hard Port”.

The situational awareness is:

• Course change suddenly to 073.2 degrees from one minute before 052.2 degrees.(sighted)
• Turning Rate 21 degrees per minutes promote the chance of lost control. (Suspect)
• Port side crossing vessel is at starboard side now. (sighted)
• One overtaking vessel at starboard side is at ownship bow now. (sighted)
• Ownship has collision risk with starboard side crossing vessel after 3.0 minutes. (sighted)
• Last minute ownship had reduced speed 2 knots with no actual effect on collision avoidance. (sighted)
• What to do with this collision risk? (suspect)
• One overtaken vessel at port side is still slower than ownship. (skill by comparing vector length)

After 05 minutes exercise time lapsed:

Ownship speed is 15.0 knots again reduced from 16.6, 18.3, 20.7, 18.0 kts with engine output 50% after two minute and further reduce at 04 minute 20 seconds.

Ownship course altered 2 degrees to starboard side 069.7 degrees from 067.1, 073.2 052 degrees. Using rudder angle “Starboard 15” then “Hard starboard “over one minute time.

The situational awareness is:

• Course change slowly to 069.7 degrees from one minute before 067.1 degrees.(sighted)
• Vessel is steady on traffic general flow direction. (sighted)
• One overtaking vessel passed ownship bow from starboard side to port now. (sighted)
• Ownship has collision risk with starboard side crossing vessel after 2.0 minutes. (sighted)
• Ownship had reduced speed 3.3 knots over two minutes time with no actual effect on collision avoidance. (sighted)
• Ownship had used “starboard 15” 40 seconds and “hard starboard” 20 seconds rudder. (sighted)
• Course changed from 069. to 067.1 degree with no actual effect on collision avoidance. (sighted)
• This minute must be very painful for ship handler. (rule or suspect)
• Ownship speed is 15 knots now. One minute run in advance is 0.25 Nautical Mile or 463 meter. This is about 1.5 ship’s length for this Panamax vessel. (sighted) Remember the first exercise we had demonstrated the turning characteristics.

Please refer to turning characteristics above,  

• Origin ship position is white ship.
• Point of origin is Own Ship Bridge.
• Green ship represents the end of first stage of turning where ship bow cannot leave original course line.
• This ship's length is about 230 meters; two ship's length is about 0.25 NM as the drawing above. This 0.25 NM distance is in while semi-circle lines.

We have some observations to note:

• In the first stage (0.25 NM), Own Ship is helpless in collision risk. Any rudder order (5^0, 10^0, 20^0,30⁰ to port or starboard side) been used is useless. Vessels just collide with anything ahead. Own Ship can only hope for reducing the collision momentum by crash astern.
• In the second stage (0.25 - 0.5 NM), Own Ship bow can clear original course line, but ship stern had not yet. More rudder order (5^0, 10^0, 20^0,30⁰ to port or starboard side), more quick the bow deviate from original course line. Vessel may collide with her stern in this distance range.
• In the third stage (0.5 - 0.75 NM), Own Ship body can clear original course line, but the beam distance might not enough. More rudder order (5^0, 10^0, 20^0,30⁰ to port or starboard side), more quick ship body deviate from original course line.

It is irrelevant for the rudder initiated for collision avoidance, there is first minute to wait and second minutes to see and third minutes to stop before thing get out of hands. (rule).

• What to do with this collision risk now? (Prey for God, Goddess, astonished, or knows what is going on)

After 06 minutes exercise time lapsed:

Ownship speed is 13.3 knots again reduced from 15.0, 16.6, 18.3, 20.7, 18.0 kts with engine output 50% after two minute and further reduce at 04 minute 20 seconds to 15%.

Ownship course altered 15 degrees to starboard side 084.1 degrees from 069.7, 067.1, 073.2 052 degrees. Using rudder angle “Hard starboard “ 20 seconds and midship.

The situational awareness is:

• Course change suddenly to 084.1 degrees from one minute before 069.7 degrees.(sighted)
• The turning rate is 14 degrees per minutes. (sighted)
• It is OK for 14 degrees per minutes. (skill by knowing ownship)
• The job remained is to stop the turn immediately. (suspect)

End of Exercise 04-03