Conduct of Vessels in Restricted Visibility.
a) This rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility.
(b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and condition of restricted visibility. A power driven vessel shall have her engines ready for immediate manoeuvre.
Note: This is repetition of Rule 6. Engines are always ready for immediate manoeuvre. Do not get confused during Viva. As a good practice of seamanship, Engineers are warned about possible manoeuvring.
(c) Every vessel shall have due regard to the prevailing circumstances and conditions of restricted visibility when complying with the Rules of Section I of this Part. (Conduct of vessel during ANY condition of visibility)
(d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration in course, so far as possible the following shall be avoided:
(i) An alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken;
(ii) An alteration of course toward a vessel abeam or abaft the beam.
(e) Except where it has been determined that a risk of collision does not exist, every vessel which hears apparently forward of her beam the fog signal of another vessel, or which cannot avoid a close-quarters situation with another vessel forward of her beam, shall reduce her speed to be the minimum at which she can be kept on her course. She shall if necessary take all her way off and in any event navigate with extreme caution until danger of collision is over.
The important point to consider with this rule is that it applies when “navigating in or near an area of restricted visibility”. This means that you could for example, be steaming in beautifully clear visibility on one side of the ship, but have a fog bank fairly close by, on the other. In this situation, this rule will apply. Logically, the other rules cannot apply in cases of bad visibility, as the ships are not in sight of one another. Thus the priorities defined in Rule 18 in Section II are no longer valid, as it is impossible to determine if another vessel is fishing, NUC or RAM etc.
With regard to paragraph (b), the use of engines as a means of collision avoidance has already been discussed, but nevertheless, they should be ready for manoeuvre, as their use may be the only course of action that the OOW has, to avoid a collision.
Paragraph (c) includes an assessment of safe speed that must be made, that takes into account your radar characteristics and efficiency which is a reference back to Rule 6 paragraph (b) and Rule 7 (b) and (c). Here you are dealing with adjustment of speed (normally reduction). There is no guarantee of “Pick up” range of other vessels on Radar. Irony is, what is visible on Radar may not be visible due to short range of Navigational lights. Even at 6 NM range, when you have established risk of collision vessels may not be visible to each other. To make matters more confusing, one of the vessels may not have operational radar. This points out complexities of rules. Eventually it means you must be alert to detect vessels, take prompt action to judge risk and take appropriate action.
Paragraph (d) is rather efficient and very easy to follow, provided only two ships are involved. Unfortunately, in many circumstances, a risk of collision exists with several vessels at once and manoeuvring for one of them can bring others onto a collision course. An OOW must always be aware of the “big” picture within a range of say 6 miles.
Paragraph (e) is self-explanatory BUT it must be remembered that this is not always the best course of action to take. Basically it says that if you detect unknown object forward of beam, create more time for observations and action. Like you stop ball while playing football before kicking it with plan.
Also, it is worth noting that Rule 13 does not apply in restricted visibility. Remember what the first paragraph of Rule 13 says “Notwithstanding anything contained in the Rules of Part B, Sections I and II any vessel overtaking any other shall keep out of the way of the vessel being overtaken.” Rule 19 is in Part B, Section III of the regulations and Rule 13 only applies to Part B, sections I and II. However, again with the practice of good seamanship, an overtaking vessel would be expected to keep clear. So, when are you overtaking in fog? You cannot see the other vessel and so cannot determine if you are approaching from more than 22½ ° abaft her beam. You must therefore plot the other vessel on radar, in order to determine her course and speed. Having therefore gained knowledge of the other vessel’s course etc., it would seem to be a fairly pointless exercise, to then try and determine when you are exactly 22½ degrees, or more, abaft her beam. Having plotted the other vessel, it would be good practice to assume that you are overtaking her, if you are approaching the other vessel from aft of her beam. Although this is not laid down in the Rules, the practice of good seamanship would determine that this would be a prudent course of action to take.
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