Handbook of the Nautical Rules of the Road by Llana & Wisneskey

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Rule 18 -- Responsibilities Between Vessels


Most of the other Rules for vessels in sight of each other deal with encounters between two ordinary power-driven vessels, and Rule 12 covers encounters between sailing vessels. Rule 18 tells you what to do when you encounter a vessel that is fundamentally different from your own.

Rule 18 lists the various classes of vessels in a "pecking order" of privilege. Vessel classes perceived to be more maneuverable are directed to keep out of the way of classes thought to be less maneuverable. Naturally, there are exceptions in the Rule because perceptions do not necessarily hold true in reality. Remember that this Rule applies only to vessels in sight of each other.

The vessel directed to keep out of the way must follow Rule 8 (Action to Avoid Collision) and Rule 16 (Action by Give-way Vessel).


INTERNATIONAL

INLAND

(a) A power-driven vessel underway shall keep out of the way of:

(i) a vessel not under command;

(ii) a vessel restricted in her ability to maneuver;

(iii) a vessel engaged in fishing;

(iv) a sailing vessel.

(a) A power-driven vessel underway shall keep out of the way of:

(i) a vessel not under command;

(ii) a vessel restricted in her ability to maneuver;

(iii) a vessel engaged in fishing; and

(iv) a sailing vessel.

 

Ordinary power-driven vessels that are underway must stay out of the way of the other types of vessels. Power-driven vessels that are not underway--that is, that are anchored, aground, or made fast to the shore--of course do not have to keep out of the way of other vessels. Vessels that are anchored or aground must display the required lights and shapes for those situations.


INTERNATIONAL

INLAND

(b) A sailing vessel underway shall keep out of the way of:

(i) a vessel not under command;

(ii) a vessel restricted in her ability to maneuver;

(iii) a vessel engaged in fishing.

(b) A sailing vessel underway shall keep out of the way of:

(i) a vessel not under command;

(ii) a vessel restricted in her ability to maneuver; and

(iii) a vessel engaged in fishing.

 

Sailing vessels that are underway must stay out of the way of vessels not under command, restricted in ability to maneuver, or engaged in fishing. (The definitions of these vessel classes are contained in Rule 3.)


INTERNATIONAL

INLAND

(c) A vessel engaged in fishing when underway shall, so far as possible, keep out of the way of:

(i) a vessel not under command;

(ii) a vessel restricted in her ability to maneuver.

(c) A vessel engaged in fishing when underway shall, so far as possible, keep out of the way of:

(i) a vessel not under command; and

(ii) a vessel restricted in her ability to maneuver.

 

Vessels engaged in fishing (when underway) must keep out of the way of vessels not under command or restricted in ability to maneuver, but "only so far as possible." Some fishing operations so severely hamper a vessel's ability to maneuver that it would be physically impossible to keep out of the way of another vessel. For example, a trawler's speed is often limited to a few knots when its trawl is out, and a purse seiner may not be able to move at all while drawing in its net. Rule 18 certainly does not require that a fishing vessel cut loose its gear in order to move out of the way of another hampered vessel.

Vessels restricted in ability to maneuver and vessels not under command are given equal status. All vessels under normal circumstances are required to stay out of the way of these two classes.

What happens when a vessel not under command encounters a vessel restricted in ability to maneuver (or if both belong to the same class)? Both should take action to avoid collision.


INTERNATIONAL

(d)(i) Any vessel other than a vessel not under command or a vessel restricted in her ability to maneuver shall, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draft, exhibiting the signals in Rule 28.

 

Paragraph (d) of International Rule 18 concerns vessels constrained by draft to a relatively narrow natural or dredged channel. If a vessel in such a situation turned off its course, it would run aground. Predicting the action the Rule requires of a vessel constrained by draft is uncertain, so the formal concept of a vessel constrained by draft was not adopted in Inland Rule 18.

The International Rule requires that vessels (except those not under command and those restricted in ability to maneuver), if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by draft. The general requirement attempts to resolve a situation that varies greatly with particular circumstances. As a result, there are two problems with the requirement.

First, the escape clause "if the circumstances of the case admit" relies on the judgment of the operator of the vessel approaching the vessel constrained by draft. This introduces uncertainty on the part of the constrained vessel because the other operator's judgment can only be guessed.

Second, the "shall not impede the passage" requirement places responsibility on the nonconstrained vessel to stay out of the way while it is at long range. Notwithstanding that obligation, if it gets close enough for risk of collision to arise, the constrained vessel will be obligated to act according to the more general Steering and Sailing Rules, which may make it the give-way vessel. The non-constrained vessel will in all cases continue to be charged with staying out of the way. (Confused? See Rule 8(f) for "shall not impede" guidance.)


INTERNATIONAL

(ii) A vessel constrained by her draft shall navigate with particular caution having full regard to her special condition.

 

Perhaps because of the uncertainty involved, the Rule commands vessels constained by draft to navigate "with particular caution." This means that the constrained vessel must be ready to take collision-avoiding action at all times, which for a vessel constrained by draft means limiting speed and having engines ready for maneuver.


INTERNATIONAL

INLAND

(e) A seaplane on the water shall, in general, keep well clear of all vessels and avoid impeding their navigation. In circumstances, however, where risk of collision exists, she shall comply with the Rules of this Part.

(e) A seaplane on the water shall, in general, keep well clear of all vessels and avoid impeding their navigation. In circumstances, however, where risk of collision exists, she shall comply with the Rules of this Part.

 

The last paragraph in Rule 18 covers seaplanes, an encounter with which is probably a rarity for most mariners. Rule 18 directs seaplanes to stay well clear of other vessels if possible. Otherwise, a seaplane is to follow the Rules as would a comparable power-driven vessel. While landing and taking off, seaplanes cannot effectively turn, but they can maneuver when taxiing. Vessels operating in the vicinity of a seaplane taking off or landing should note, as a precaution, the pilot's forward visibility may become completely blocked by the aircraft's raised nose.

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