Isolated Danger Mark (or Buoy) (G.B.)
2-6-100
Alternative term: Obstruction Mark (or Buoy) (U.S.A.)
A mark (or buoy) used alone to indicate a dangerous reef or shoal. The mark (or buoy) may be passed on either hand.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
