---
kind: "section"
citation: "33 C.F.R. § 84.15"
title: "33"
number: "84.15"
heading: "Horizontal sectors."
url: "https://uscodex.org/cfr/33/84.15"
---

# §84.15. Horizontal sectors.

- (a)
  - (i) 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 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](/cfr/33/21.md) ([§ 83.21](/cfr/33/83.21.md) of this chapter). 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.
- (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](/cfr/33/30.md) ([§ 83.30](/cfr/33/83.30.md) of this chapter), which need not be placed at an impracticable height above the hull, and the all-round white light described in [Rule 23(e)](/cfr/33/23.md?p=e) ([§ 83.23(e)](/cfr/33/83.23.md?p=e) of this chapter), which may not be obscured at all.
- (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 to appear, as far as practicable, as one light at a minimum distance of one nautical mile.

## Notes

### Amendments

[79 FR 37921, July 2, 2014, as amended by USCG-2016-0498, 82 FR 35080, July 28, 2017]

### Authority

Authority: Sec. 303, Pub. L. 108-293, 118 Stat. 1042 (33 U.S.C. 2071); Department of Homeland Security Delegation No. 0170.1.

### Source

Source: 79 FR 37921, July 2, 2014, unless otherwise noted.

### Amendments

[79 FR 37921, July 2, 2014, as amended by USCG-2016-0498, 82 FR 35080, July 28, 2017]