Rule 27 — Vessels Not Under Command or Restricted in Ability to Manoeuvre

A vessel not under command shall exhibit: (a) two all-round red lights in a vertical line; (b) two balls in a vertical line (day). A vessel restricted in her ability to manoeuvre shall exhibit: (a) three all-round lights — red, white, red (top to bottom); (b) ball, diamond, ball shapes in a vertical line (day). These vessels shall also show sidelights and sternlight when making way.