When two masthead lights are carried the after one shall be vertically higher than the forward one at least?

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Índice Show

The vertical positioning of Masthead lights
What part of the COLREGs covers the vertical positioning of Masthead lights?
At what height should masthead lights be carried?
What is the separation of two masthead lights?
Horizontal positioning of Masthead lights
A quick summary of the Masthead Light distances
Digging Deeper into the COLREGs
4 lights configurations sailing
Sailing and Motoring
Pushing from ahead or towing alongside
Fishing, other than trawling
Constrained by draught
Restricted in her ability to manoeuvre
Hovercraft, hydrofoil ferry

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Navsregs>COLREGS>Masthead light position

More delving into the detail of navigation lights, this time its the positioning of masthead lights.

Annex 1 part 2.

On a power-driven vessel of 20 meters or more in length:

The forward masthead light, or if only one masthead light is carried, then that light is:

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

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.

The masthead light of a power-driven vessel of less than 12 meters in length:

These 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 side-lights 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

The masthead light or lights prescribed in shall be so placed as to be above and clear of all other lights and obstructions except for Not Under Command Lights and Restricted in Manoeuvrability.

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.

What part of the COREGS covers the horizontal positioning of Navigation lights?

Annex 1 3 Horizontal positioning and spacing of lights

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.

A quick summary of the Masthead Light distances

Digging Deeper into the COLREGs

If you want to go beyond the text of the Collision Regulations then this is the book I recomend. Copies are a but pricey, but worth the outlay.

Click here for a search that will find older and cheaper editions>

Tagged Navigation Lights, Navigational equipment

Arcs of visibility of sternlight and sidelights

Masthead light
means a white light placed over the fore and aft centreline of the vessel showing an unbroken light over an arc of the horizon of 225° and so fixed as to show the light from right ahead to 22.5° abaft the beam on either side of the vessel.
Sidelight means a green light on the starboard side and a red light on the port side each showing an unbroken light over an arc of the horizon of 112.5° and so fixed as to show the light from right ahead to 22.5° abaft the beam on its respective side.
In a vessel of less than 20 metres in length the sidelights may be combined in one lantern carried on the fore and aft centreline of the vessel.
Sternlight
means a white light placed as nearly as practicable at the stern showing an unbroken light over an arc of the horizon of 135° and so fixed as to show the light 67.5° from right aft on each side of the vessel.
Towing light
means a yellow light having the same characteristics as the sternlight.
All-round light
means a light showing an unbroken light over an arc of the horizon of 360°.
Flashing light
means a light flashing at regular intervals at a frequency of 120 flashes or more per minute.

White light

Yellow light

Green light

Red light

Yellow flashing light

Optional white light

A power-driven vessel underway shall exhibit:

a masthead light forward;
a second masthead light abaft of and higher than the forward one; except that a vessel of less than 50 metres in length shall not be obliged to exhibit such light but may do so;
sidelights;
a sternlight.

Power driven vessel underway, longer than 50 m


Abeam, port side	Ahead	Astern
Power driven vessel underway, shorter than 50 m


Abeam, port side	Ahead	Astern

↑ Power-driven vessel underway.

↑ Power-driven vessel underway – less than 50 m in length

↑ A vessel proceeding under sail which has her engine running shall exhibit, forward where it can best be seen, a conical shape, apex downwards.
She shall exibit lights according to a power-driven vessel.

A sailing vessel underway shall exhibit:

In a sailing vessel of less than 20 metres in length the lights may be combined in one lantern carried at or near the top of the mast where it can best be seen.

A sailing vessel underway may, in addition to the lights, exhibit at or near the top of the mast, where they can best be seen, two all-round lights in a vertical line, the upper being red and the lower green, but these lights shall not be exhibited in conjunction with the combined lantern.

4 lights configurations sailing

Sailing vessel 1


Abeam, port side	Ahead	Astern
Sailing vessel 2


Abeam, port side	Ahead	Astern
Sailing vessel 3


Abeam, port side	Ahead	Astern
Sailing vessel 4


Abeam, port side	Ahead	Astern

↑ Sailing vessel underway.
Configuration 1, and if sidelights are combined on the bow: configuration 4

↑ Sailing vessel underway – less than 20 meters in length.
Configuration 2

↑ Sailing vessel underway.
Configuration 3

A sailing vessel of less than 7 metres in length shall, if practicable, exhibit the lights prescribed above, but if she does not, she shall have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision.

A vessel under oars may exhibit the lights prescribed in this Rule for sailing vessels, but if she does not, she shall have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision.

Sailing and Motoring

A vessel proceeding under sail which has her engine running shall exhibit, forward where it can best be seen, a conical shape, apex downwards.
She shall exibit lights according to a power-driven vessel.

Sailing and motoring
	Day sign

Abeam, port side	Ahead	Astern

Anchoring

A vessel at anchor shall according to Rule 30 (a) (b) exhibit where it can best be seen:

in the fore part, an all-round white light or one ball;
at or near the stern and at a lower level than the light prescribed in Rule 30(a)(i), an all-round white light.

Anchored vessel, longer than 50 m
	Day sign (1 black sphere)

Abeam, port side	Ahead	Astern
Anchored vessel, shorter than 50 m
	Day sign (1 black sphere)

Abeam, port side	Ahead	Astern
Anchored sailing boat
	Day sign (1 black sphere)

Abeam, port side	Ahead	Astern

↑ Vessel at anchor – less than 50 m in length.

↑ Vessel at anchor with deck illumination.

↑ Vessel aground – less than 50 m in length.

A vessel aground shall according to Rule 30 (d) exhibit the lights prescribed in Rule 30(a) or (b) and in addition, if practicable, where they can best be seen;

two all-round red lights in a vertical line;
three balls in a vertical line.

Aground, longer than 50 m
	Day sign (3 black spheres)

Abeam, port side	Ahead	Astern

Towing

A power-driven vessel when towing shall exhibit:

two masthead lights in a vertical line. When the length of the tow, measuring from the stern of the towing vessel to the after end of the tow exceeds 200 metres, three such lights in a vertical line; Rule 24;
sidelights;
a sternlight;
a towing light in a vertical line above the sternlight;
when the length of the tow exceeds 200 metres, a diamond shape where it can best be seen.

Tugboat longer than 50 m – tow longer than 200 m

Abeam, port side

Ahead, Day sign (diamond shapes)	Ahead	Astern
Tugboat shorter than 50 m – tow longer than 200 m

Abeam, port side

Ahead, Day sign (diamond shapes)	Ahead	Astern
Tugboat longer than 50 m – tow shorter than 200 m
	Abeam, port side

Ahead, Day sign (no shapes)	Ahead	Astern
Tugboat shorter than 50 m – tow shorter than 200 m
	Abeam, port side

Ahead, Day sign (no shapes)	Ahead	Astern

↑ Power-driven vessel towing astern towing vessel less than 50 m in length;

length of tow exceeds 200 m.

↑ Power-driven vessel towing astern towing vessel less than 50 m in length;

length of tow 200 m or less.

↑ Vessel or object being towed – length of tow exceeds 200 m.

An inconspicuous, partly submerged vessel or object, or combination of such vessels or objects being towed; Rule 24 (g), shall exhibit:

if it is less than 25 metres in breadth, one all-round white light at or near the forward end and one at or near the after end except that dracones need not exhibit a light at or near the forward end;
if it is 25 metres or more in breadth, two additional all-round white lights at or near the extremities of its breadth;
if it exceeds 100 metres in length, additional all-round white lights between these lights so that the distance between the lights shall not exceed 100 metres;
a diamond shape at or near the aftermost extremity of the last vessel or object being towed and if the length of the tow exceeds 200 metres an additional diamond shape where it can best be seen and located as far forward as is practicable.

Tow shorter than 200 m, object shorter than 100 m

Abeam, port side
Tow longer than 200 m, object shorter than 100 m

Abeam, port side
Tow longer than 200 m, object longer than 100 m

Abeam, port side
Tow longer than 200 m, object longer than 100 m & wider than 25 m

Abeam, port side (note that often a fifth round white light in the center is added)

Ahead	Astern
Tow longer than 200 m, any object size

Day sign, Abeam, port side

Pushing from ahead or towing alongside

When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit they shall be regarded as a power-driven vessel and exhibit the normal lights.

A power-driven vessel when pushing ahead or towing alongside, except in the case of a composite unit; Rule 24 (c), shall exhibit:

two masthead lights in a vertical line;
sidelights;
a sternlight.

A vessel or object being towed shall exhibit:

sidelights;
a sternlight;
when the length of the tow exceeds 200 metres, a diamond shape where it can best be seen.
Provided that any number of vessels being towed alongside or pushed in a group shall be lighted as one vessel,
a vessel being pushed ahead, not being part of a composite unit, shall exhibit at the forward end, sidelights;
a vessel being towed alongside shall exhibit a sternlight and at the forward end, sidelights.

Pushing from ahead

Abeam, port side

Ahead	Astern
Towing alongside
	Abeam, port side

Ahead	Astern

↑ Pushing: composite unit underway (ridged, so treated as a single power driven vessel).

↑ Pushing: vessel being pushed ahead, not being part of a composite unit.

↑ Vessel being towed alongside.

A vessel engaged in fishing, whether underway or at anchor, shall exhibit only the lights and shapes prescribed below; Rule 26

A vessel when engaged in trawling, by which is meant the dragging through the water of a dredge net or other apparatus used as a fishing appliance, shall exhibit:

two all-round lights in a vertical line, the upper being green and the lower white, or a shape consisting of two cones with their apexes together in a vertical line one above the other;
a masthead light abaft of and higher than the all-round green light; a vessel of less than 50 metres in length shall not be obliged to exhibit such a light but may do so;
when making way through the water, in addition to the lights prescribed hereh, sidelights and a sternlight.
when shooting nets, white light over white light (Flag Z by day);
when hauling nets, white light over red light (Flag G by day);
When nets are caught on the bottom, red light over red light (Flag P by day).

Fishing vessel, trawling
	Day sign

Abeam, port side Optional white light if shorter than 50 m	Ahead Optional white light if shorter than 50 m	Astern
Fishing vessel, trawling, shooting nets (white over white)
	Day sign • Flag Z

Abeam, port side	Ahead	Astern
Fishing vessel, trawling, hauling nets (white over red)
	Day sign • Flag G

Abeam, port side	Ahead	Astern
Fishing vessel, trawling, nets caught on bottom (red over red)
	Day sign • Flag P

Abeam, port side	Ahead	Astern

↑ Vessel engaged in trawling – not making way.

↑ Vessel engaged in trawling – not making way; vessel less than 50 m in length.

↑ Vessel engaged in trawling – making way; vessel less than 50 m in length.

When pair trawling, each vessel shows searchlights on water aiming forward (Flag T by day); Rule 26 (f) (b)ǂ(2)

Trawling in span, shooting nets

Ahead	Astern

Fishing, other than trawling

A vessel engaged in fishing, other than trawling, according to Rule 26 (c) shall exhibit:

two all-round lights in a vertical line, the upper being red and the lower white, or a shape consisting of two cones with apexes together in a vertical line one above the other;
when there is outlying gear extending more than 150 metres horizontally from the vessel, an all-round white light or a cone apex upwards in the direction of the gear;
when making way through the water, in addition to the lights prescribed here, sidelights and a sternlight.

Fishing vessel, other than trawling, outlying gear >150 m
	Day sign

Abeam, port side	Ahead	Astern

↑ Vessel engaged in trawling – making way.
See Fishing – Trawling section above…

↑ Vessel engaged in fishing other than trawling – making way.

↑ Vessel engaged in fishing other than trawling – not making way.

Purse Seiners will exhibit two all-round yellow lights in a vertical line, flashing alternately; Rule 26 (f) 3ǂ(iii)

Purse seiner fishing vessel

Abeam, port side	Ahead	Astern

Constrained by draught

A vessel constrained by her draught / draft may, (and not “shall”!) in addition to the lights prescribed for power-driven vessels, exhibit where they can best be seen three all-round red lights in a vertical line, or as day sign a cylinder, Rule 28

Power driven vessel, underway, constrained by her draught
	Day sign (black vertical cylinder)

Abeam, port side	Ahead	Astern

↑ Vessel constrained by her draft / draught.

↑ Vessel not under command “NUC” – not making way.

↑ Vessel not under command “NUC” – making way.

A vessel not under command, sometimes knows as a NUC vessel, shall according to Rule 27(a) exhibit:

two all-round red lights in a vertical line where they can best be seen;
two spherical shapes in a vertical line where they can best be seen; and
when making way through the water also normal sidelights and a sternlight (not shown in the examples below).

Vessel not under command, not making way through the water
	Day sign (two black spheres)

Abeam, port side	Ahead	Astern
Sailing boat, no wind, no mechanical propulsion

Abeam, port side	Ahead	Astern

Restricted in her ability to manoeuvre

A vessel restricted in her ability to manoeuvre, sometimes knows as a RAM vessel, except a vessel engaged in mine clearance operations, shall according to Rule 27(b) exhibit:

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;
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;
when making way through the water, also a masthead light or lights, sidelights and a sternlight

Restricted in her ability to manoeuvre, not making way through the water
	Day sign: two black spheres and in the middle a black diamond shape

Abeam, port side	Ahead	Astern
Restricted in her ability to manoeuvre, making way through the water, longer than 50 m

Abeam, port side	Ahead	Astern

↑ Vessel restricted in her ability to manoeuvre – making way; vessel less than 50 m in length.

↑ Vessel restricted in her ability to manoeuvre – at anchor; vessel less than 50 m in length.

↑ Vessel engaged in towing operation which severely restricts towing vessel and her tow in their ability to deviate from their course – length of tow does not exceed 200 m; towing vessel less than 50 m in length.

A vessel engaged in dredging or underwater operations, when restricted in her ability to manoeuvre; Rule 27(d), shall exibit

two all-round red lights or two balls in a vertical line to indicate the side on which the obstruction exists;
two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass; and
when at anchor (or not making way), the lights or shapes prescribed in this section instead of the lights or shapes prescribed in Rule 30

Dredging or underwater operations, shorter than 50 m, not making way

Ahead, day signs	Ahead	Astern
Dredging or underwater operations, shorter than 50 m, making way

Ahead, day signs	Ahead	Astern
Dredging or underwater operations, longer than 50 m, making way

Ahead, day signs	Ahead	Astern

↑ Vessel engaged in dredging or underwater operations when restricted in ability to manoeuvre – making way with an obstruction on the starboard side.

↑ Vessel engaged in dredging or underwater operations when restricted in ability to manoeuvre – not making way with an obstruction on the starboard side.

↑ Vessel engaged in dredging or underwater operations when restricted in ability to manoeuvre – not making way with an obstruction on the port side.

Rule 27(e)

Small diving vessel
or	Day signs

Abeam, port side	Ahead	Astern

↑ Small vessel engaged in diving operations.

↑ Vessel engaged on pilotage duty – underway.

↑ Vessel engaged on pilotage duty – at anchor; vessel of less than 50 m in length.

Rule 29, duty shall exhibit:

at or near the masthead, two all-round lights in a vertical line, the upper being white and the lower red;
when underway, in addition, sidelights and a sternlight; as shown in the example below.

Pilot boat, shorter than 50 m

Abeam, starboard side	Ahead	Astern

Hovercraft, hydrofoil ferry

An air-cushion vessel when operating in non-displacement mode shall, besides a masthead light forward, (plus a masthead light abaft if longer than 50 m) sidelights and a sternlight, exhibit an all‑round flashing yellow light (faster than 2 flashes per second). Rule 23(b)

Also a hydrofoil ferry or high speed catamaran when acting as ferry is often allowed under local regulations to exhibit an all-round flashing yellow light.

Hovercraft, longer than 50 m

Abeam, port side	Ahead	Astern

↑ Air-cushion vessel when operating in the nondisplacement mode – vessel less than 50 m in length.

↑ Vessel engaged in mineclearance operations – vessel less than 50 m in length, starboard side.

↑ Vessel engaged in mineclearance operations, port side.

A vessel engaged in mine clearance operations shall in addition to the lights prescribed for a power-driven vessel, or to the lights or shape prescribed for a vessel at anchor, exhibit three all-round green lights or three balls. One of these lights or shapes shall be exhibited near the mast 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 metres of the mine clearance vessel. Rule 27(f)