Wednesday, October 8, 2008

Lesson 27: More Rules

PART B – Section I, (Subpart I)- Steering and Sailing Rules: Conduct of Vessels in Any Condition of Visibility

Rule 4, Application

International and Inland – Rules in this Section apply to any condition
of visibility.


• This section applies to all vessels, at any time, any where, and in any weather.

Rule 5, Look Out

International and Inland – Every vessel shall at all times maintain a
proper look-out by sight and hearing as well as by all available means
appropriate in the prevailing circumstances and conditions so as to
make a full appraisal of the situation and risk of collision.


• During day or night, and in conditions of restricted visibility, whether the radar is being used or not, a lookout must be present.
• In order to keep a proper look-out a mariner must use his sight and hearing and, if necessary, any optical or electronic aids which are available so as to detect other vessels as early as possible and to determine whether there is risk of collision. In addition, he must pay attention to what is happening on his own vessel, keeping a check on the steering and be certain that equipment being used in the navigation of the vessel is functioning correctly.
• The use of radar does not dispense with the need for a visual look-out.
• It is not sufficient to have the radar switched on. In order to keep a proper look-out required by the Rules, the radar must be properly used.
• The look-out should report any lights, vessels, or large floating objects which he sees, and in low visibility, any fog signals which he hears. However, when in traffic, he cannot be expected to see everything. The look-out must use discretion and report the lights or objects which are likely to bring risk of collision, especially small craft which may not have been observed from the bridge.
• The duty of a proper look-out applies also when a vessel is at anchor, especially if there is a strong current is running, or if other vessels are navigating near by.

Rule 6, Safe Speed

International and Inland – Every vessel shall at all times proceed at a
speed so that she can take proper and effective actions to avoid
collision and be stopped within a distance appropriate to the prevailing
circumstances and conditions.

In determining safe speed the following factors shall be among those
taken in account.

(a) By all vessels: (i) The state of visibility. (ii) The traffic density including the concentration of fishing vessels or any other vessels. (iii) The maneuverability of the vessel with special reference to stopping distance and turning ability in the prevailing conditions. (iv) At night, the presence of background light such as from shore lights or from back scatter from her own lights. (v) The state of wind, sea, current, and the proximity of navigational hazards. (vi) The draft in relation to the available depth of the water.

(b) Additionally, by vessels with operational radar: (i) The characteristics, efficiency and limitations of the radar equipment. (ii) Any constraints imposed by the radar scale in use. (iii) The effect on radar detection of the sea state, weather, and other sources of interference. (iv) The possibility that small vessels, ice, and other floating objects may not be detected by radar at an adequate range. (v) The number, location, and movements detected by radar, and. (vi) The more exact assessment of the visibility that may be possible when radar is used to determine the range of vessels or other objects in the vicinity.


• The use of radar does not dispense with the need to maintain a safe speed even if moderate or slow in nature.
• It is not sufficient to have the radar switched on. In order to keep a safe speed as directed by the Rules, the radar must be properly used.

Rule 7, Risk of Collision

(a) International and Inland – Every vessel shall use all available means appropriate to the prevailing circumstances and conditions to determine if risk of collision exists. If there is any doubt such risk shall be deemed to exist.
(b) International and Inland – Proper use shall be made of radar equipment if fitted and operational, including long range scanning to obtain early warning of risk of collision and radar plotting of equivalent systematic observation of detected objects.
(c) International and Inland – Assumptions shall not be made on the basis of scanty information especially scanty radar information.
(d) International and Inland – In determining if risk of collision exists the following considerations shall be among those taken into account: (i) Such risk shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change; and. (ii) (Such risk may sometimes exist even when an appreciable bearing change is evident, particularly when approaching a very large vessel or a tow or when approaching vessel at close range.


• Risk of collision is a difficult term to define, but risk may be considered to begin when two vessels have approached so close to one another that a departure from the Rules by either vessel would bring the danger of collision.
• It is the compass bearing of an approaching vessel which is referred to, not the relative bearing. Sighting an approaching vessel against the components of the vessel’s structure is a poor substitute for taking compass bearings, and can be very misleading if the direction of the ship’s bow is not taken into account on each occasion. Risk of collision should be deemed to exist if the bearing does not appreciably change. A constant bearing would indicate probability of collision if neither vessel took action, but a slowing changing bearing may also indicate risk of collision.
• Plotting is generally considered to be the best means of determining whether if there is risk of collision with another vessel or other vessels. The principles of relative plotting should well understood by all observers as this method is best when determining the closest position of approach with another vessel.
• When using radar the importance of shadow sectors or blind areas should be kept in mind. To determine if present, the vessel’s course should altered at regular intervals so a “new” radar scan can be observed. The radar screen should be kept under continuous observation by a crew member that has been trained to interpret the radar display and properly evaluate the operating condition of the equipment.
• There is no obligation to use radar if the equipment is not functioning properly, provided it can be shown that there is a genuine fault. Every effort should be made to have it repaired and returned to service as soon as possible

Rule 8, Action to Avoid Collision

(a) International and Inland – Any action taken to avoid collision shall, if the circumstances of the case admit, be positive, made in ample time and with due regard to the observance of good seamanship.
(b) International and Inland – Any alteration of course or speed to avoid collision shall, if the circumstances of the case admit, be large enough to be readily apparent to another vessel observing or by radar; a succession of small alterations of course or speed should be avoided.
(c) International and Inland – If there is sufficient sea room, alteration of course alone may be the most effective action to avoid a close-quarter situation provided that it is made in good time, is substantial and does not result in another close quarter situation.
(d) International and Inland – Action taken to avoid collision with another vessel shall be such as to result in passing at a safe distance. The effectiveness of the actions shall be carefully checked until the other vessel is finally past and clear.
(e) International and Inland – If necessary to avoid collision or allow more time to assess the situation, a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion.
(f) (i) A vessel which, by any of these rules, is required not to impede the passage or safe passage of another vessel shall, when required by the circumstances of the case, take early action to allow sufficient sea room for the safe passage of the other vessel. (ii) A vessel required not to impede the passage or safe passage of another vessel is not relieved of this obligation if approaching the other vessel so as to involve risk of collision and shall, when taking action, have full regard to the action which maybe required by the rules of this part. (iii) A vessel, the passage of which is not to be impeded remains fully obligated to comply with the rules of this part when the two vessels are approaching one another so as to involve the risk of collision.


• Changes of course-speed should be large enough to be apparent.
• In ample time, execute a large change in course. Show a side.
• Change in course (> 5 degrees) is more obvious than a change in speed.
• Any and all action(s) must result in a safe distance.
• If all else fails, slacken speed or take all way off (stop).
• Within the rules, the phrase “so far as the circumstances of the case admit” refers to what’s going on.

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