Section 10 Vertical Sectors — International
(a) The vertical sectors of electric lights as fitted, with the exception of lights on sailing vessels underway, shall be such that
(i) at least the required minimum intensity is maintained at all angles from five degrees above to five degrees below the horizontal,
(ii) at least 60 per cent of the required minimum intensity is maintained from 7.5 degrees above to 7.5 degrees below the horizontal.
(b) In the case of sailing vessels underway, the vertical sectors of electric lights as fitted shall be such that
(i) at least the required minimum intensity is maintained at all angles from five degrees above to five degrees below the horizontal,
(ii) at least 50 per cent of the required minimum intensity is maintained from 25 degrees above to 25 degrees below the horizontal.
(c) In the case of lights other than electric these specifications shall be met as closely as possible.
(d) Where from any sufficient cause it is impracticable for an unmanned barge or log tow in Canadian waters of a roadstead, harbour, river, lake or inland waterway to exhibit lights that comply with the vertical sector requirements of paragraph (a), the lights on the unmanned barge or log tow need not comply with the vertical sector requirements but shall maintain the required minimum intensity on the horizontal.