ANNEX I: INTERNATIONAL POSITIONING & TECHNICAL DETAILS OF LIGHTS
& SHAPES
Definition
Vertical
Positioning and Spacing of Lights
Horizontal
Positioning and Spacing of Lights
Details
of location of direction-indicating lights for fishing vessels, dredgers
and vessels engaged in underwater operations
Screens
for Sidelights
Shapes
Color
Specification of Lights
Intensity
of Lights
Horizontal
Sectors
Vertical
Sectors
Intensity
of Non-Electric Lights
Maneuvering
Light
High
Speed Craft
Approval
1. Definition
The term "height above the hull" means height above the uppermost
continuous deck. This height shall be measured from the position vertically
beneath the location of the light.
2. Vertical positioning
and spacing of lights
-
On a power-driven vessel of 20 meters or more in length the masthead
lights shall be placed as follows:
- the forward masthead light, or if only one masthead
light is carried, then that light, at a height above the hull of not less
than 6 meters, and, if the breadth of the vessel exceeds 6 meters, then
at a height above the hull not less than such breadth, so however that
the light need not be placed at a greater height above the hull than 12
meters;
- when two masthead lights are carried the after
one shall be at least 4.5 meters vertically higher than the forward one.
- The vertical separation of masthead lights of power-driven
vessels shall be such that in all normal conditions of trim the after
light will be seen over and separate from the forward light at a distance
of 1000 meters from the stem when viewed from sea level.
- The masthead light of a power-driven vessel of 12
meters but less than 20 meters in length shall be placed at a height above
the gunwale of not less than 2.5 meters.
- A power-driven vessel of less than 12 meters in length
may carry the uppermost light at a height of less than 2.5 meters above
the gunwale. When, however, a masthead light is carried in addition to
sidelights and a sternlight or the all-round light prescribed in rule
23(c)(i) is carried in addition to sidelights, then such masthead light
or all-round light shall be carried at least 1 meter higher than the sidelights.
- One of the two or three masthead lights prescribed
for a power-driven vessel when engaged in towing or pushing another vessel
shall be placed in the same position as either the forward masthead light
or the after masthead light; provided that, if carried on the aftermast,
the lowest after masthead light shall be at least 4.5 meters vertically
higher than the forward masthead light.
-
- The masthead light or lights prescribed in Rule
23(a) shall be so placed as to be above and clear of all other lights
and obstructions except as described in subparagraph (ii).
- When it is impracticable to carry the all-round
lights prescribed by Rule 27(b)(i) or Rule 28 below the masthead lights,
they may be carried above the after masthead light(s) or vertically in
between the forward masthead light(s) and after masthead light(s), provided
that in the latter case the requirement of Section 3(c) of this Annex
shall be complied with.
- The sidelights of a power-driven vessel shall be
placed at a height above the hull not greater than three quarters of that
of the forward masthead light. They shall not be so low as to be interfered
with by deck lights.
- The sidelights, if in a combined lantern and carried
on a power-driven vessel of less than 20 meters in length, shall be placed
not less than 1 meter below the masthead light.
-
When the Rules prescribe two or three lights to be carried in a vertical
line, they shall be spaced as follows:
- on a vessel of 20 meters in length or more such
lights shall be spaced not less than 2 meters apart, and the lowest of
these lights shall, except where a towing light is required, be placed
at a height of not less than 4 meters above the hull;
- on a vessel of less than 20 meters in length
such lights shall be spaced not less than 1 meter apart and the lowest
of these lights shall, except where a towing light is required, be placed
at a height of not less than 2 meters above the gunwale;
- when three lights are carried they shall be equally
spaced.
- The lower of the two all-round lights prescribed
for a vessel when engaged in fishing shall be at a height above the sidelights
not less than twice the distance between the two vertical lights.
- The forward anchor light prescribed in Rule 30(a)(i),
when two are carried, shall not be less than 4.5 meters above the after
one. On a vessel of 50 meters or more in length this forward anchor light
shall be placed at a height of not less than 6 meters above the hull.
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3. Horizontal positioning
and spacing of lights
- When two masthead lights are prescribed for a power-driven
vessel, the horizontal distance between them shall not be less than one
half of the length of the vessel but need not be more than 100 meters.
The forward light shall be placed not more than one quarter of the length
of the vessel from the stem.
- On a power-driven vessel of 20 meters or more in
length the sidelights shall not be placed in front of the forward masthead
lights. They shall be placed at or near the side of the vessel.
- When the lights prescribed in Rule 27(b)(i) or Rule
28 are placed vertically between the forward masthead light(s) and the
after masthead light(s) these all-round lights shall be placed at a horizontal
distance of not less than 2 meters from the fore and aft centerline of
the vessel in the athwartship direction.
- When only one masthead light is prescribed for a
power-driven vessel, this light shall be exhibited forward of amidships;
except that a vessel of less then 20 meters in length need not exhibit
this light forward of amidships but shall exhibit it as far forward as
is practicable.
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4. Details of location of
direction-indicating lights for fishing vessels, dredgers and vessels
engaged in underwater operations
- The light indicating the direction of the outlying
gear from a vessel engaged in fishing as prescribed in Rule 26(c)(ii)
shall be placed at a horizontal distance of not less than 2 meters and
not more than 6 meters away from the two all-round red and white lights.
This light shall be placed not higher than the all-round white light prescribed
in Rule 26(c)(i) and not lower than the sidelights.
- The lights and shapes on a vessel engaged in dredging
or underwater operations to indicate the obstructed side and/or the side
on which it is safe to pass, as prescribed in Rule 27(d)(i) and (ii),
shall be placed at the maximum practical horizontal distance, but in no
case less than 2 meters, from the lights or shapes prescribed in Rule
27(b)(i) and (ii). In no case shall the upper of these lights or shapes
be at a greater height than the lower of the three lights or shapes prescribed
in Rule 27(b)(i) and (ii).
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5. Screens for sidelights
The sidelights of vessels of 20 meters or more in length shall be fitted
with inboard screens painted matt black, and meeting the requirements
of Section 9 of this Annex. On vessels of less than 20 meters in length
the sidelights, if necessary to meet the requirements of Section 9 of
this Annex, shall be fitted with inboard matt black screens. With a combined
lantern, using a single vertical filament and a very narrow division between
the green and red sections, external screens need not be fitted.
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6. Shapes
-
Shapes shall be black and of the following sizes:
- a ball shall have a diameter of not less than
0.6 meter;
- a cone shall have a base diameter of not less
than 0.6 meter and a height equal to its diameter;
- a cylinder shall have a diameter of at least
0.6 meter and a height of twice its diameter;
- a diamond shape shall consist of two cones as
defined in (ii) above having a common base.
- The vertical distance between shapes shall be at
least 1.5 meter.
- In a vessel of less than 20 meters in length shapes
of lesser dimensions but commensurate with the size of the vessel may
be used and the distance apart may be correspondingly reduced.
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7. Color specification of
lights
The chromaticity of all navigation lights shall conform to the following
standards, which lie within the boundaries of the area of the diagram
specified for each color by the International Commission on Illumination
(CIE).
The boundaries of the area for each color are given by indicating the corner
coordinates, which are as follows:
(i) White:
x 0.525 0.525 0.452 0.310 0.310 0.443
y 0.382 0.440 0.440 0.348 0.283 0.382
(ii) Green:
x 0.028 0.009 0.300 0.203
y 0.385 0.723 0.511 0.356
(iii) Red:
x 0.680 0.660 0.735 0.721
y 0.320 0.320 0.265 0.259
(iv) Yellow:
x 0.612 0.618 0.575 0.575
y 0.382 0.382 0.425 0.406
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8. Intensity of lights
(a) The minimum luminous intensity of lights shall be calculated by
using the formula:
I = 3.43 x 106 x T x D2 x K-D
where:
I is luminous intensity in candelas
under service conditions,
T is threshold factor 2 x 10-7 lux,
D is range of visibility (luminous range) of the light in nautical
miles,
K is atmospheric transmissivity. For prescribed lights the value of
K shall be 0.8, corresponding to a meteorological visibility of approximately
13 nautical miles.
(b) A selection of figures derived from the formula is given in the
following table:
| Range
of visibility (luminous range) of light in nautical miles |
Luminous
intensity of light in candelas for K = 0.8 |
| D |
I |
| 1 |
0.9 |
| 2 |
4.3 |
| 3 |
12 |
| 4 |
27 |
| 5 |
52 |
| 6 |
94 |
Note:
The maximum luminous intensity of navigation lights should be limited
to avoid undue glare. This shall not be achieved by a variable control
of the luminous intensity.
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9. Horizontal sectors
-
- In the forward direction, sidelights as fitted
on the vessel shall show the minimum required intensities. The intensities
shall decrease to reach practical cut-off between 1 degree and 3 degrees
outside the prescribed sectors.
- For sternlights and masthead lights and at 22.5
degrees abaft the beam for sidelights, the minimum required intensities
shall be maintained over the arc of the horizon up to 5 degrees within
the limits of the sectors prescribed in Rule 21. From 5 degrees within
the prescribed sectors the intensity may decrease by 50 percent up to
the prescribed limits; it shall decrease steadily to reach practical cut-off
at not more than 5 degrees outside the prescribed sectors.
-
- All-round lights shall be so located as not to
be obscured by masts, topmasts or structures within angular sectors of
more than 6 degrees, except anchor lights prescribed in Rule 30, which
need not be placed at an impracticable height above the hull.
- If it is impracticable to comply with paragraph
(b)(i) of this section by exhibiting only one all-round light, two all-round
lights shall be used suitably positioned or screened so that they appear,
as far as practicable, as one light at a distance of one mile."
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10. Vertical sectors
-
The vertical sectors of electric lights as fitted, with the exception
of lights on sailing vessels underway shall ensure that:
- at least the required minimum intensity is maintained
at all angles from 5 degrees above to 5 degrees below the horizontal;
- at least 60 percent of the required minimum intensity
is maintained from 7.5 degrees above to 7.5 degrees below the horizontal.
-
In the case of sailing vessels underway the vertical sectors of electric
lights as fitted shall ensure that:
- at least the required minimum intensity is maintained
at all angles from 5 degrees above to 5 degrees below the horizontal;
- at least 50 percent of the required minimum intensity
is maintained from 25 degrees above to 25 degrees below the horizontal.
- In the case of lights other than electric these specifications
shall be met as closely as possible.
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11. Intensity of non-electric
lights
Non-electric lights shall so far as practicable comply with the minimum
intensities, as specified in the Table given in Section 8 of this Annex.
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12. Maneuvering light
Notwithstanding the provisions of paragraph 2(f) of this Annex the maneuvering
light described in Rule 34(b) shall be placed in the same fore and aft
vertical plane as the masthead light or lights and, where practicable,
at a minimum height of 2 meters vertically above the forward masthead
light, provided that it shall be carried not less than 2 meters vertically
above or below the after masthead light. On a vessel where only one masthead
light is carried the maneuvering light, if fitted, shall be carried where
it can best be seen, not less than 2 meters vertically apart from the
masthead light.
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13. High Speed Craft*
- The masthead light of high speed craft may be placed
at a height related to the breadth of the craft lower than that prescribed
in paragraph 2(a)(i) of this Annex, provided that the base angle of the
isosceles triangles formed by the sidelights and masthead light, when
seen in end elevation, is not less than 27°.
- On high-speed craft of 50 meters or more in length,
the vertical separation between foremast and mainmast light of 4.5 meters
required by paragraph 29a)(ii) of this annex may be modified provided
that such distance shall not be less than the value determined by the
following formula:
y = (a+17Y)C +2
1000
where:
y is the height of the mainmast light above the foremast light in meters;
a is the height of the foremast light above the water surface in service
condition in meters;
Y is the trim in service condition in degrees;
C is the horizontal separation of masthead lights in meters.
* Refer to the International Code of Safety for High-Speed Craft, 1994
and the International Code of Safety for High-Speed Craft, 2000
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14. Approval
The construction of lights and shapes and the installation of lights
on board the vessel shall be to the satisfaction of the appropriate authority
of the State whose flag the vessel is entitled to fly.