Colregs Questions and Answers (Q & A)

Rule 6

Safe speed

The answers can be found in the respective Rules and Paragraphs in the book"International Regulations for Preventing Collisions at Sea (Colregs) by Capt. Pierre Deseck and/or in the Colregs Presentation (on DVD), also by Capt. Pierre Deseck

Q = Question; A= Answer

Q 6-1
Define the term “safe speed”.

A 6-1
Rule 6 and Par. 6.1 General
Click on safe speed for a summary


Q 6-2
Which factors shall be taken into account by all vessels in determining a safe speed ?

A 6-2
Rule 6 (a) and Par. 6.2 till 6.7.
Click on determining a safe speed for a summary


Q 6-3
Comment the notions “state of visibility” versus “safe speed”.

A 6-3
Par. 6.2, The state of visibility.


Q 6-4
Which factors shall be taken into account with regards to the traffic density ?

A 6-4
Par. 6.3, The traffic density.
Click on traffic density for a summary


Q 6-5
Which are the factors that determine the manoeuvrability of a vessel ?

A 6-5
Par 6.4, The manoeuvrability of the vessel.
Click on manoeuvrability of a vessel for a summary


Q 6-6
Which "precautionery measures” should you take before you were ap­pointed as chief mate on a large ship or on a ship with unusual manoeu­vring characteristics ?

A 6-6
Merchant Shipping Notice No M.1015, Training for masters and chief mates of large ships and ships with unusual manoeuvring characteris­tics.


Q 6-7
What effect can shore lights or back scatter of the vessel’s ow light have on the identification of navigation lights ?

A 6-7
Par. 6.5, Background lights.
Click on shore lights for a summary


Q 6-8
What are the consequences of the wind, sea and current on a ship proceeding at a reduced speed ?

A 6-8
Par 6.6, The state of wind, sea and current.
Click on wind and sea for a summary


Q 6-9
How will a vessel behave when she has insufficient water under the keel ?

A 6-9
Par. 6.7, The draught in relation to the available depth of water.
Click on insufficient water under the keel for a summary


Q 6-10
What is interaction and what are the dangers inherent to it.

A 6-10
Marine Guidance Note, MGN 199 (M), Dangers of interaction.


Q 6-11
Which factors shall be taken into account by vessels with operational ra­dar ?

A 6-11
Rule 6 (b) and Par. 6.9, For vessels with operational radar.


Q 6-12
Which elements determine the efficiency of the radar ?

A 6-12
Statutory Instrument 1993 No. 93, The Merchant Shipping (Naviga­tional Equipment) Regulations 1993, Part IV, Radar Installations.


Q 6-13
Enumerate the main characteristics which determine the efficiency of the radar.

A 6-13
Par. 6.9.1, Characteristics, efficiency, limitations of radar equipment.
Click on efficiency of the radar for a summary


Q 6-14
Give the different types of radar equipement that can be encountered on board vessels.

A 6-14
Par. 6.9.1, Characteristics, efficiency, limitations of radar equipment, fourth paragraph.


Q 6-15
Comment the choice of range scale to be used.

A 6-15
Par. 6.9.2, Range scale in use.
Click on choice of range scale for a summary


Q 6-16
Describe the interferences that can make some echoes difficult to observe.

A 6-16
Par. 6.9.3, The sea state, weather conditions and other sources of . in­terference


Q 6-17
What precautions shall you take in coastal waters and in some regions (especially in winter) when performing radar observations ?

A 6-17
Par. 6.9.4, Small vessels, ice and other floating objects.


Q 6-18
Which vessels are required to carry a radar reflector ?

A 6-18
Radar reflectors and SOLAS Regulation 19, par. 2.1.7


Q 6-19
Give the main spacifications to which radar reflectors must comply.

A 6-19 Radar reflectors.


Q 6-20
What precautionary measurers shall you take when a great number of echoes are detedted on the radar

A 6-20
Par 6.9.5, The number, location and movement of vessels detedted.


Q 6-21
Can the radar help you in assissing the visibility ? Explain

A 6-21
Par. 6.9.6, Assessment of visibility.


Q 6-22
What is the degree of confidence you can put in the use of radar as a means to avoid collision ?

A 6-22
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Sub. par 2.1, General


Q 6-23
How should you interpret the observed echoes on the radar ?

A 6-23
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Sub. par. 2.2, 2.3 and 2.4, Interpretation.


Q 6-24
How can you estimate the degree of risk of collision with another vessel ?

A 6-24
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Par. 2.5, Plotting.


Q 6-25
Enumerate the factors that should influence your choice of range scales for observation by radar.

A 6-25
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Par. 2.6, Choice of range scale.


Q 6-26
How should you use and appreciate radar observations as a means of avoiding collision ?

A 6-26
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Par 2.7 till 2.10, Ap­preciation.


Q 6-27
When is it opportune to practice with radar ?

A 6-27
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Par 2.11, Clear weather practice.


Q 6-28
When should the radat be kept operational ?

A 6-28
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Par. 2.12, Operation, and par 2.13, Radar watchkeeping.


Q 6-29
What do you know about parallel index techniques ?

A 6-29
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 3, The Use of radar and plotting aids, Par. 2.14 till 2.20, Parallel index rechniques.


Q 6-30
When and how should the performance of the radar be checked ?

A 6-30
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Par. 2.21 till 2.24, Regular operational checks.


Q 6-31
Which additional checks should you perform with a ARPA and ATA ?

A 6-31
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 2, The Use of radar and plotting aids, Par 2.25 till 2.27, Electronic radar plotting aids (ARPA and ATA).


Q 6-32
Should you rely 100% on the GPS and GLONASS system ?

A 6-32
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par. 4, Global posi­tioning system (GPS).


Q 6-33
What di you know about ECDIS ?

A 6-33
Marine Guidance Note 63 MGN (M + F), Use of Electronic Aids to Nav­igation, Par 5, Electronic charts.

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