(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:
where:
|
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.” |