33 CFR § 83.26 - Fishing vessels (Rule 26).
(a) A vessel engaged in fishing, whether underway or at anchor, shall exhibit only the lights and shapes prescribed in this Rule.
(b) 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:
(i) 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;
(c) A vessel engaged in fishing, other than trawling, shall exhibit:
(i) 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;
(ii) When there is outlying gear extending more than 150 meters horizontally from the vessel, an all-round white light or a cone apex upward in the direction of the gear;
(f) Additional signals for fishing vessels fishing in close proximity:
(i) The lights mentioned herein shall be placed where they can best be seen. They shall be at least 0.9 meters apart but at a lower level than lights prescribed in this Rule. The lights shall be visible all round the horizon at a distance of at least 1 mile but at a lesser distance from the lights prescribed by paragraphs (a) through (c) of this Rule for fishing vessels.
(ii) Signals for trawlers.
(1) Vessels when engaged in trawling, whether using demersal or pelagic gear, may exhibit:
(A) When shooting their nets: Two white lights in a vertical line;
(B) When hauling their nets: One white light over one red light in a vertical line;
(C) When a net has come fast upon an obstruction: Two red lights in a vertical line.
(2) Each vessel engaged in pair trawling may exhibit:
(A) By night, a searchlight directed forward and in the direction of the other vessel of the pair;
(B) When shooting or hauling their nets or when their nets have come fast upon an obstruction, the lights prescribed in paragraph (f)(ii)(1) of this Rule.
(iii) Signals for purse seiners.
(1) Vessels engaged in fishing with purse seine gear may exhibit two yellow lights in a vertical line. These lights shall flash alternately every second and with equal light and occultation duration. These lights may be exhibited only when the vessel is hampered by its fishing gear.