# The Dockyard Port of Plymouth Order 2020, 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.

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Source: https://www.legislation.gov.uk/uksi/2020/1261/schedule/2/paragraph/2 (the official version)
Page: https://openlegislation.uk/dockyard-port-of-plymouth-order-2020/schedule-2/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.