Practical reference

Quick look-ups you actually need on watch.

• IMO signal flags
  International Code of Signals alphabet flags.
• Morse code
  Maritime Morse usage including SOS.
• Knots
  Bowline, clove hitch, sheet bend, and more.
• Navigation lights
  COLREG vessel light identification.
• Sound signals
  COLREG fog and manoeuvring signals.
• Distress procedures
  Mayday format, GMDSS basics.
• Distress frequencies
  VHF channels, MF/HF, GMDSS.
• Beaufort wind scale
  Force 0 to force 12.
• Douglas sea state
  Visual sea state scale 0–9.
• Unit converters
  Knots, NM, fathoms, °F↔°C, mb↔inHg.