Seaman's Handbook

ANNEX I. Positioning and technical details of lights and shapes

(a) Shapes shall be black and of the following sizes:
  1. a ball shall have a diameter of not less than 0.6 metre:
  2. a cone shall have a base diameter of not less than 0.6 metre and a height equal to its diameter:
  3. a cylinder shall have a diameter of at least 0.6 metre and a height of twice its diameter:
  4. a diamond shape shall consist of two cones as defined in (ii) above having a common base.
(b) The vertical distance between shapes shall be at least 1.5 metre.(c) In a vessels of less than 20 metres in length shapes of lesser dimensions but commensurate with the size of the vessel may be used and the distance apart may be correspondingly reduced.