Sailed4seas的部落格

Ex 01-02-00  What is a seperation scheme ?

​​​The motto of this exercise : Safe speed can save your life, but safe position can save all troubles. (yours and other's)

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By the drawing: ownship speed vector is in 6 minutes length, there are three collision points (in yellow circle), Collision awareness are

• Own Ship original speed is 19.2 knots.
• Own Ship original course is  066 degree as shown above.

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If we display the actual ship shape on the drawing, Collision awareness are

• Ownship can notice immediately that third vessel is closer to Own Ship after 6 minutes. (sense)
• Although fishing vessel 10 on starboard side has the closest collision point No.1, (sense)
• Fishing vessel 10 arrive the collision point at about 5 minutes later. OS pass No. 1 collision point at about 3 minutes. (sense)
• Ownship and No.10 Fishing Vessel did not arrive No,1 collision point at same time. There will be no collision for ownship and NO.10 FV. (statement)
• From this picture, it is hard to say these two vessels on portside which have collision point No.2 and No.3 are arrive at same time with Own ship or not. (suspect)

If the end of two vessels speed vectors  close to each other then these two vessels has collision risk.  (rule)

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​05 minutes 24 seconds exercise time passed:

We will discuss about two parts of safety: Safe Speed and Safe Position. Let's look at the first part: safe speed.

• Vessel arrive the precautionary area with only 10.7 knots now. This means that Ownship  has reduced almost half speed, 19.2 to 10.7. (Sense) 
• All Crossing traffics (crossing vessels) already passing ahead of ownship. (sense)
• This speed reduction can save our life from collision.( statement)
• Ownship further alter course to 052 from 066 degree (general direction of traffic), 14 degrees to portside to give wide sea room for outbound vessel. (sense)
• This speed reduction can not save our trouble. Ownship have to alter course to clear collision square.(sense)

• Propeller revolution is in green color which had reduced twice in first minute for safe speed.   (sense)
• Increased twice at end of 2nd minutes and 5 minutes for rudder effects. (suspect)
• Rudder order is in light blue color. Ownship had applied Hard Port (upper part) at 3.5 minutes to start port side turn.(sense)
• Ownship used Hard Starboard (lower part) to steady at 5.0 minutes. (sense)
• Course change is 14 degrees to port side. (sense)

Ownship speed decreased or increased slowly regardless the propeller revolution increased or decreased in short interval.   (statement is a general rule of shipmanship)

Ownship's problems are threefold

1. Is speed reduction in time and effective for collision avoidance or not? (suspect)
2. How many degrees to port side is enough to make the sea room for crossing vessel? (suspect)
3. Where all these crossing vessels are going?  (Mystery?)

For suspect 1 and 2, How to control ownship speed reduction and course change is our seamanship which can be solved later in these assays. For the mystery, where all these crossing vessels are going? Problems unsolved. 

 Let's look at the second part: safe position.

Singapore Strait traffic scheme,   the precautionary area which marked with triangle are areas where the traffic can come and go in all Directions. Inside these areas, there are no traffic lanes. They are clear marked with Traffic Crossing and Ferries routs inside. All vessels can use these precautionary areas as needed. There's no general direction of traffic in precautionary area because it is not a traffic lane. In another word, these areas are the areas of trouble where others vessel's intention unclear and our course line may cross other vessel in any position and direction. ( Golden Rule )

Outbound vessels from the Harbor have three directions to go as below picture:

1. Those westbound vessels (green ship) are not threat as the "Aquarium". (sense)
2. Those vessels going eastbound (red ship) will alter course to 066 degree once clear of the separation line in middle of traffic lanes as "Mobil No.1" and "No.10 container vessel".  (sense)
3. Only those vessels continue to cross the traffic lane (yellow ship) had posed Collision risk to ownship. (Skill is to do something after check at least one criteria of concern)

Ownship should pass precautionary areas by sailing along outer limit of traffic lane where Eastbound and Westbound vessel won’t bother us.  (seamanship : blue ship) This is easy to talk here. Unfortunately, this is not a common sense of current seaman or Master on board. Generations of seaman had passed; this simple truth is not passed down or noticed by our ancestors. It is important in voyage planning and sailing around these areas.  

Also, COLREG rule 10 : A vessel using a traffic separation scheme shall: (ii) so far as practicable keep clear of a traffic separation line or separation zone;  

In collision avoidance, we need

1. the sense to know the clue (to know what is wrong, knowledge based SOP to detect)
2. the skill to judge the data sense (to do something to make sure, check out the key factors)
3. the seamanship to apply good practice in our instinct. ( to apply good practice in extremities of time …….)  

We as Officer Of Watch (OOW) reported to bridge in night watch or a Master of the ship had called in midnight for help.  

Rather than try to reduce engine  revolution  at all means  and alter course with “Hard  Port"  or  "Hard  Starboard" to make sea room  for crossing traffic  as the  OOW  in this exercise. This kind of jump out decision is lack of proper Collision Awareness training.

First Collision awareness in restrict area or narrow channel is the position. No matter you are OOW or Master, you  should check ownship position in relation to  outer limit of traffic lane immediately. 

• If starboard side has available space, ownship should adjust ownship position by altering course to starboard side immediately before the speed reduction, for safe position is more important than safe speed.  ( Golden Rule in narrow channel )
• If safe position (space on starboard side) is not available, ownship priority shift to reduce speed first with all means. Not only stop the engine but also go crash astern and rudder cycling if possible.  (Skill )   

This exercise is beginning from wrong position where our course line is close to separation line in the middle.  This is a test of

• the working habits in attending bridge duty (the instinct to check ownship position correctness)  and
• the sense to pay attention in maneuvering criteria and
• the knowledge of what to do (SOP).

Make sure ownship course line close to  outer limit of traffic lane or further away from precautionary area is prudent seamanship. (rule)

NO RIGHTS IN TRAFFIC SEPARATIONS CHEMES (quoted from North of England P&I flyer)

Rule 10 is one of the longest rules and one of the hardest to understand. Always remember the following:

• There is no right of way – a traffic separation lane does not give you right of way over any other vessels. All of the other rules continue to apply within a traffic separation scheme. (Separation scheme is for reference only.)
• The actions of vessels navigating in and near a traffic separation scheme can be unpredictable. (COLREG is like this, local authorities may not think the same. Some areas ownship will have to follow general flow of traffic flow or ownship will suffer from penalties ask by coast state.)  
• Traffic separation schemes are established in busy areas of difficult navigation. (which means Master should be on the bridge all time or master should has one OOW qualified to take care of his job for him. OOW, ask yourself are you qualified to do the job? If not, just say it to Master without shame and get help as quick as possible.)
• You can expect above-average density of traffic, crossing vessels, fishing vessels and high-speed craft.
• Study the passage before your watch, be prepared and, if you need assistance, ask for it well in advance.

Tips for navigating in traffic separation schemes are:

• Always follow all the other rules. Keep in your lane. (keep outside part of your lane if you what I mean)
• Particular caution is required at the ends of the scheme. (do not alter course too early if you are outbound and adjust your turning point as far as possible if you are inbound.)
• Avoid VHF calls to other ships – it will only distract them. (VHF call is only compulsory in harbour area by local rules of navigation)  
• Beware of fishing vessels – they are allowed to fish in traffic separation lanes. (they are constantly turning to gather fishes.)
• Look out for crossing vessels – they should cross the scheme at right angles but they may navigate parallel to the scheme for a while to find an opportunity to cross. (look out any vessels sailed close to center separation line of traffic lane which are to pass in any time.)
• Look out for high-speed craft – especially wide on your beam. (high speed craft can overtake ownship in any direction, in our head, stern or abeam.)
• If you are not happy, slow down or stop. (You will find so relaxing once speed is reduced. Always allow 6 minutes more for speed reduction to be effective.)
• Be wary at all times. (Get it done before you go to seas right here right now (knowledge). Wary is good but consuming our life and energy (sense). Get it done with corrects understanding and control in easy (good working habit).)

SUMMARY : You have no additional rights of way in a traffic separation scheme. (you had not prepared yourself before you saw these articles)

• Reduce speed; stop engine is good but ownship still approaching to dangerous area slowly if ownship heading is wrong like this exercise. (Trouble)
• If something misjudged or target vessel suddenly changed course, we will be in great Danger. (statement)

To save all these troubles, the best choice is always stay away from the trouble. (rule) 

End of Ex 01-02