(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 paragraph 2(a)(i) of this annex, provided that the base angle of the isosceles triangles formed by the sidelights and masthead light, when seen in end elevation, is not less than 27º.
(B). On high-speed craft of 50 metres or more in length, the vertical separation between foremast and mainmast light of 4.5 metres required by paragraph 2(a)(ii) of this annex may be modified provided that such distance shall not be less than the value determined by the following formula:
- y: is the height of the mainmast light above the fore mast light in metres;
- a: is the height of the foremast light above the water surface in service condition in metres;
- ψ: is the trim in service condition in degrees;
- C: is the horizontal separation of masthead lights in metres.”