Code of Federal Regulations Title 33. Navigation and Navigable Waters § 33.84.19 High-speed craft

(a) The masthead light of high-speed craft may be placed at a height related to the breadth of the craft lower than that prescribed in § 84.02(a)(i), provided that the base angle of the isosceles triangle formed by the sidelights and masthead light, when seen in end elevation is not less than 27°.

(b) On high-speed craft of 50 meters or more in length, the vertical separation between foremast and mainmast light of 4.5 meters required by § 84.02(k) may be modified provided that such distance shall not be less than the value determined by the following formula:

Where:

y is the height of the mainmast light above the foremast light in meters;

a is the height of the foremast light above the water surface in service condition in meters;

ψ is the trim in service condition in degrees;

C is the horizontal separation of masthead lights in meters.