Position of navigational lights

Introduction

The marine navigation light, also referred to as a marine signal light, serves the critical function of indicating a vessel's operational status, including its navigation direction and size, particularly during night time or low-visibility conditions. This illumination system is of paramount importance for vessels to implement avoidance protocols and effectively prevent collisions, especially in adverse conditions such as darkness or reduced visibility.

The ship's navigation signal system represents a vital component of maritime safety, constituting a pivotal lighting infrastructure to ensure secure navigation during night time operations. Adhering to international regulations for collision avoidance at sea, a comprehensive navigation signal equipment ensemble must be integrated into the vessel, encompassing ship navigation lights, ship signal lights, and a foghorn. This comprehensive navigation lighting system comprises various components, namely, a masthead light, sidelights, stern light, towing light, anchor light, yellow all-round flashing light, maneuvering signal light, and a flashing light.

Position of navigational lights

Masthead light

Masthead light means a white light placed over the fore and aft centerline of the vessel showing an unbroken light over an arc of the horizon of 225 degrees and so fixed as to show the light from right ahead to 22.5 degrees abaft the beam on either side of the vessel.

In cases where a single masthead light is employed, it should be situated at an elevation above the vessel's hull that is no less than 6 meters. If the vessel's hull width exceeds 6 meters, the masthead light should be positioned at an elevation above the hull equal to or greater than its breadth, though not exceeding 12 meters. 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.

In scenarios where two masthead lights are utilized, the rearward light must be positioned at least 4.5 meters higher in a vertical direction compared to the forward one.

COLREG/Annex I/ 9(b)(i) states that All round lights shall be so located as not to be obscured by masts, topmasts or superstructures within angular sectors of more than 6°, except anchor lights prescribed in Rule 30, which need not to be placed at an impractical height above the hull.

If it is impracticable to comply with paragraph 9(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.

The arrangement of two all-round lights shall be complied with below requirement, and Screenings details and the arrangement of obstacles are to be considered by Societies when carrying out the drawing approval process. (Refer to MSC.1/Circ.1260/Rev.1 and IACS UI COLREG 1 for more detail).

Figure 1 -  All-Round Light Requirement

Sidelights

Sidelights 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 degrees and so fixed as to show the light from right ahead to 22.5 degrees abaft the beam on its respective side. In a vessel of less than 20 meters in length the sidelights may be combined in one lantern carried on the fore and aft centerline of the vessel. The sidelights of vessels of 20 meters or more in length shall be fitted with inboard screens painted matt black.

The placement of the sidelights must adhere to specific guidelines as follows:

1. They should not be positioned in front of the forward masthead light.
2. Ideally, they should be located at or near the sides of the vessel, and it is recommended that they be placed no more than one-tenth of the vessel's breadth inboard (up to a maximum distance of 1 meter from the side). In cases where adhering to this requirement is not feasible (e.g., on small ships with narrow superstructures), exceptions may be granted based on acceptance by the Flag Administration.
3. The inboard screens of the sidelights should be coated with matte black paint to reduce glare.
4. In accordance with COLREG Annex I, section 9(a) (i), the full intensity of the sidelights must be maintained within the forward direction of 1° outside the designated sector, with the practical cutoff occurring between 1° and 3°. This ensures that other vessels can identify a "head-on situation" as per COLREG rule 14. (Please refer to IMSC.1/Circ.1427 for details.)
5. According to COLREG Annex I, section 10(a)(i), if sidelights are positioned at or near the side and are not visible from all angles within a range of 5 degrees above to 5 degrees below the horizontal, including the 1° toe-in sector (as seen in area A), the installation may still be acceptable. However, in such cases, the installed sidelights must be visible from sea level under all normal conditions of trim corresponding to the vessel's lightest seagoing draught, at a minimum distance of 1000 meters measured from the stern. (This applies to ships contracted for construction on or after July 1, 2019, and further details can be found in MSC.1/Circ.1577 and IACS UI COLREG 5.)

Figure 2

Anchor lights

A vessel at anchor must display, in the most visible location:

1. Forward: An all-around white light or one ball.
2. Near the stern, at a lower position than the aforementioned light, another all-around white light.

The forward anchor light should be positioned no less than 4.5 meters above the aft anchor light. On a vessel with a length of 50 meters or more, the front anchor light must be situated at a minimum height of 6 meters above the hull.

Other lights

Stern light means a white light placed as nearly as practicable at the stern showing an unbroken light over an arc of the horizon of 135 degrees and so fixed as to show the light 67.5 degrees from right aft on each side of the vessel.

Towing light means a yellow light having the same characteristics as the 'stern light'.

Flashing light means a light flashing at regular intervals at a frequency of 120 flashes or more per minute.

Particulars of all navigational lights