33 CFR § 84.05 - Screens.
(a) The sidelights of vessels of 20 meters or more in length shall be fitted with matt black inboard screens and meet the requirements of § 84.15. On vessels of less than 20 meters in length, the sidelights, if necessary to meet the requirements of § 84.15, shall be fitted with matt black inboard 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.
(b) On power-driven vessels less than 12 meters in length constructed after July 31, 1983, the masthead light, or the all-round light described in Rule 23(d)(§ 83.23(d) of this chapter) shall be screened to prevent direct illumination of the vessel forward of the operator's position.
The following state regulations pages link to this page.