Implementation a fishing vessel engaged in trawling

A FISHING VESSEL ENGAGED IN TRAWLING:
A fishing vessel engaged in trawling shall exhibit:
– Two all-round lights in a vertical line, the upper being green and the lower white, in the day time a shape consisting of two cones with their apexes together in a vertical line one above the other.
– A masthead light abaft of and higher than the all-round green light, a vessel of less than 50 meters in length shall not be obliged to exhibit such a light but may do so.
– When making way through the water in addition, sidelights and a sternlight.