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

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Rule 27 -- Vessels Not Under Command or Restricted in Their Ability to Maneuver


Vessels not under command and vessels restricted in their ability to maneuver are treated similarly under the Rules, as their combined status under Rule 27 reflects. The Rule 3 definition of a "vessel not under command" is that of a vessel "unable to maneuver as required" of ordinary vessels because of "exceptional circumstance." Rule 3 defines a "vessel restricted in her ability to maneuver" as one unable to keep out of the way because of "the nature of her work." In both cases, the vessel cannot physically comply with the Rules for ordinary vessels, and so they are granted special privileges. Rule 18 requires all other vessels to keep out of the way of these two classes of vessels.


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(a) A vessel not under command shall exhibit:

(i) two all-round red lights in a vertical line where they can best be seen;

(ii) two balls or similar shapes in a vertical line where they can best be seen;

(iii) when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.

(a) A vessel not under command shall exhibit:

(i) two all-round red lights in a vertical line where they can best be seen;

(ii) two balls or similar shapes in a vertical line where they can best be seen; and

(iii) when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.

 

A vessel not under command has usually suffered a disability, which is not easy to predict or classify. An example would be a vessel with a disabled rudder. The navigation light requirement is, therefore, brief and general.


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(b) A vessel restricted in her ability to maneuver, except a vessel engaged in mineclearance operations, shall exhibit:

(i) three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white;

(ii) three shapes in a vertical line where they can best be seen. The highest and lowest of these shapes shall be balls and the middle one a diamond;

(iii) when making way through the water, a masthead light or lights, sidelights and a sternlight, in addition to the lights prescribed in subparagraph (i);

(iv) when at anchor, in addition to the lights or shapes prescribed in subparagraphs (i) and (ii), the light, lights, or shape prescribed in Rule 30.

(b) A vessel restricted in her ability to maneuver, except a vessel engaged in mineclearance operations, shall exhibit:

(i) three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white;

(ii) three shapes in a vertical line where they can best be seen. The highest and lowest of these shapes shall be balls and the middle one a diamond;

(iii) when making way through the water, masthead lights, sidelights and a sternlight, in addition to the lights prescribed in subparagraph (b)(i); and

(iv) when at anchor, in addition to the lights or shapes prescribed in subparagraphs (b)(i) and (ii), the light, lights, or shape prescribed in Rule 30.

 

Unlike the not-under-command category, vessel classifications within the restricted-in-ability-to-maneuver category are predictable and are listed in the Rule 3 definition. Rule 27, starting with paragraph (b), gives general navigation light requirements and then more specific requirements for several vessel activities that restrict maneuverability.

The lights described in paragraph (b) are not to be displayed by a vessel engaged in mineclearance, even though the mineclearing vessel is regarded as being restricted in its ability to maneuver. Separate lighting requirements for mineclearance are given in paragraph (f).

As is also the case with vessels engaged in fishing, vessels restricted in ability to maneuver are required to display additional lights when making way through the water. Anchor lights, as described in Rule 30, are to be displayed while at anchor in addition to the lights indicating restricted ability to maneuver, except that vessels restricted in ability to maneuver because of dredging or underwater operations, and when an obstruction exists, do not display Rule 30 anchor lights when anchored (see paragraph (d)).


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(c) A power-driven vessel engaged in a towing operation such as severely restricts the towing vessel and her tow in their ability to deviate from their course shall, in addition to the lights or shapes prescribed in Rule 24(a), exhibit the lights and shapes prescribed in sub-paragraphs (b)(i) and (ii) of this Rule.

(c) A vessel engaged in a towing operation which severely restricts the towing vessel and her tow in their ability to deviate from their course shall, in addition to the lights or shapes prescribed in sub-paragraphs (b)(i) and (ii) of this Rule, exhibit the lights or shape prescribed in Rule 24.

 

Under most circumstances, vessels engaged in towing do not have any privileges over ordinary power-driven vessels. In cases where a towing operation "severely restricts the towing vessel and her tow in their ability to deviate from their course," the towing vessel is considered to be restricted in its ability to maneuver and is accorded special status.

In such situations Rule 27(c) requires the display of both Rule 24 towing lights and Rule 27(b) restricted-in-ability-to-maneuver lights. The latter lights are to be displayed where they can best be seen. They should be at a lower level than the masthead lights if practicable, but they may be higher; see Annex I - 2(f)(ii) / Section 84.03(f)(2).

The red-white-red all-round lights do not have to be in a vertical line with the masthead lights and may be off the centerline. Only the towing vessel displays the lights for a vessel restricted in ability to maneuver, not the vessel being towed.


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(d) A vessel engaged in dredging or underwater operations, when restricted in her ability to maneuver, shall exhibit the lights and shapes prescribed in subparagraphs (b)(i), (ii) and (iii) of this Rule and shall in addition, when an obstruction exists, exhibit:

(i) Two all-round red lights or two balls in a vertical line to indicate the side on which the obstruction exists;

(ii) Two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass;

(iii) When at anchor, the lights or shapes prescribed in this paragraph instead of the lights or shape prescribed in Rule 30.

(d) A vessel engaged in dredging or underwater operations, when restricted in her ability to maneuver, shall exhibit the lights and shapes prescribed in subparagraphs (b)(i), (ii), and (iii) of this Rule and shall in addition, when an obstruction exists, exhibit:

(i) two all-round red lights or two balls in a vertical line to indicate the side on which the obstruction exists;

(ii) two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass; and

(iii) when at anchor, the lights or shapes prescribed by this paragraph, instead of the lights or shapes prescribed in Rule 30 for anchored vessels.

 

Paragraphs (d) and (e) give further details for vessels restricted in ability to maneuver because they are engaged in dredging or underwater operations, including diving. Paragraph (d) gives requirements only for hampered vessels having an obstruction projecting out from one side of the vessel. The obstruction could be a dredging arm or a float or other equipment used to support underwater operations. (Separate requirements for special lighting of dredge pipelines are contained in Annex V to the Inland Rules.)

Vessels displaying the obstruction lights required by this paragraph do not also display Rule 30 anchor lights, when anchored, but vessels engaged in dredging and underwater operations when no obstruction exists are required to comply with Rule 30 when anchored.


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(e) Whenever the size of a vessel engaged in diving operations makes it impracticable to exhibit all lights and shapes prescribed in paragraph (d) of this Rule, the following shall be exhibited:

(i) Three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white;

(ii) A rigid replica of the International Code flag "A" not less than 1 meter in height. Measures shall be taken to ensure its all-round visibility.

(e) Whenever the size of a vessel engaged in diving operations makes it impracticable to exhibit all lights and shapes prescribed in paragraph (d) of this Rule, the following shall instead be exhibited:

(i) Three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white.

(ii) A rigid replica of the International Code flag "A" not less than 1 meter in height. Measures shall be taken to ensure its all-round visibility.

 

Paragraph (e) provides for vessels too small to comply with the requirements of paragraph (d) for vessels engaged in diving operations. Paragraph (e) is clearly aimed at the small vessel conducting diving operations, regardless of whether an obstruction on one side of the vessel exists. The paragraph (b) requirements for sidelights and sternlight when making way cannot be disregarded for small vessels engaged in diving operations, nor can the Rule 30 requirement to display an anchor light when anchored. Paragraph (g) of Rule 27 makes clear the intent.

Paragraph (e) excuses the display of obstruction lights and shapes and excuses the display of the ball-diamond-ball day shape array if the proper-size International Code flag "A" is displayed instead. Flags smaller than one meter are not permitted for small vessels, even though shapes of reduced size are permitted on vessels less than twenty meters long. Although a flag that big will seem large to people on a relatively small dive boat, a smaller flag would probably go unnoticed by a larger vessel approaching the area.


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(f) A vessel engaged in mineclearance operations shall in addition to the lights prescribed for a power-driven vessel in Rule 23 or to the lights and shape prescribed for a vessel at anchor in Rule 30 as appropriate, exhibit three all-round green lights or three balls. One of these lights or shapes shall be exhibited near the foremast head and one at each end of the fore yard. These lights or shapes indicate that it is dangerous for another vessel to approach within 1000 meters of the mineclearance vessel.

(f) A vessel engaged in mineclearance operations shall, in addition to the lights prescribed for a power-driven vessel in Rule 23 or to the lights and shape prescribed for a vessel at anchor in Rule 30 as appropriate, exhibit three all-round green lights or three balls. One of these lights or shapes shall be exhibited near the foremast head and one at each end of the fore yard. These lights or shapes indicate that it is dangerous for another vessel to approach within 1000 meters of the mineclearance vessel.

 

Vessels engaged in clearing mines (or the old term "minesweeping") display a unique combination of navigation lights to warn others of their dangerous operations. These lights are carried in addition to the lights carried by an ordinary vessel.


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(g) Vessels of less than 12 meters in length, except those engaged in diving operations, shall not be required to exhibit the lights and shapes prescribed in this Rule.

(g) A vessel of less than 12 meters in length, except when engaged in diving operations, is not required to exhibit the lights or shapes prescribed in this Rule.

 

Paragraph (g) exempts small vessels from the light and shape requirements for vessels not under command and restricted in ability to maneuver. Such small vessels presumably could not then claim the status of vessels in such situations and would not be given the privileges accompanying such status unless the small vessel's predicament were recognized by other means.

Small vessels engaged in diving operations do not have this blanket exemption but may comply with the alternative requirements of paragraph (e).


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(h) The signals prescribed in this Rule are not signals of vessels in distress and needing assistance. Such signals are contained in Annex IV to these Regulations.

(h) The signals prescribed in this Rule are not signals of vessels in distress and needing assistance. Such signals are contained in Annex IV to these Rules.

 

The final paragraph in Rule 27 makes clear that even though a vessel not under command (or less likely, a vessel restricted in ability to maneuver) may actually be in distress, the lights and shapes required by this Rule do not indicate distress and need of assistance. If you do in fact need assistance, use one or more of the signals listed in Annex IV. A vessel may be not under command for any number of reasons, and many of those would not require outside assistance.

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