Paragraph 2 Submarines secured to a buoy
(1)
A submarine secured to a buoy in the dockyard port must display an all-round amber flashing light at a frequency of between 90 and 105 flashes per minute—
(a)
between sunset and sunrise; and
(b)
at any other time when there is restricted visibility.
(2)
The requirement in subparagraph (1) applies in addition to any other requirement to exhibit a light under regulation 4 (prevention of collision) of the Collision Regulations.