9. pants

Horizontal

sectors

(a) (i) In the forward direction,

sidelights as fitted on the vessel must show the minimum required

intensities. The intensities shall decrease to reach practical

cut-off between 1 degree and 3 degrees outside the prescribed

sectors.

(ii) 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 per cent up to the prescribed limits; it shall decrease

steadily to reach practical cut-off at not more than 5 degrees

outside the prescribed limits.

(b) (i) 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.

(ii) 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.