Orientation

  • Abaft — toward the stern, relative to a point.
  • Athwartship — across the ship, at right angles to the centreline.
  • Fore and aft — along the length of the ship.
  • Starboard / Port — right and left sides facing forward. Port and left both have four letters.

Measurement

  • Draught — vertical distance from keel to waterline.
  • Freeboard — vertical distance from waterline to the main deck.
  • Under-keel clearance — depth of water beneath the keel.
  • Knot — one nautical mile (1852 m) per hour.

Motion

  • Heave — vertical motion; surge — fore and aft; sway — side to side.
  • Roll — about the longitudinal axis; pitch — about the transverse; yaw — about the vertical.

A word to the new officer

Learn these words properly and use them exactly. Ambiguity in a nautical term, at the wrong moment, is a navigational error with a polite face.