Small Vessels: Mast Light Height Calculation

For small vessels exceeding 20 meters in overall length, the mast light must be positioned at least 6 meters above the uppermost continuous deck and at a height equal to or greater than the maximum beam.
However, if the maximum speed exceeds the value calculated by the formula, the angle of elevation of the mast light as viewed from the side lights may be 27 degrees or greater.
This calculation determines the maximum ship speed based on the formula and also indicates the minimum height of the mast light above the side lights for vessels capable of speeds exceeding the formula’s value.