33 C.F.R. § 85.3 Signals for trawlers.
Title 33 - Navigation and Navigable Waters
(a) Vessels when engaged in trawling, whether using demersal or pelagic gear, may exhibit: (1) When shooting their nets: two white lights in a vertical line; (2) When hauling their nets: one white light over one red light in a vertical line; (3) When the net has come fast upon an obstruction: two red lights in a vertical line. (b) Each vessel engaged in pair trawling may exhibit: (1) By night, a searchlight directed forward and in the direction of the other vessel of the pair; (2) When shooting or hauling their nets or when their nets have come fast upon an obstruction, the lights prescribed in paragraph (a) of this section.
Title 33: Navigation and Navigable Waters
PART 85—ANNEX II: ADDITIONAL SIGNALS FOR FISHING VESSELS FISHING IN CLOSE PROXIMITY
§ 85.3 Signals for trawlers.

