Boat Terminology
Part IV

Continuation of Boat Terminology Part III.


  • Nautical mile: A unit of distance based on 1 minute of latitide. It's approximately 1852 meters.
  • Neap tide: A tide where the tidal range is small and streams are at their weakest.
  • No go zone: The sector within a yacht cannot sail.
  • Nominal range: The nominal range of a light is dependent on the intensity of the light in meteorological visibility of 10 miles. This takes no note of the curvature of the Earth. This range is shown on the charts.
  • North-up mode: A stabilized radar picture when North is at the top of the screen.
  • Not under command: A vessel that through some exceptional circumstances is unable to manoeuvre as required by the IRPCS.


  • Occulting light: The light is on for longer than it is off.
  • On the bow: A sector within 45˚ either side of the bow.
  • On the quarter: A sector within 45˚ either side of the stern.
  • Open: When 2 leading marks are not in line, they are described as open.
  • Outhaul: A means of pulling a mainsail towards the end of the boom.
  • Overfalls: A turbulent sea caused by a sudden change in water depth. The effect increases in a strong tidal stream.
  • Overtaking light: The 135˚ white light at the stern.


  • Painter: The line used to secure or tow a dinghy.
  • Pay out: To ease out a line or rope slowly.
  • Period: The time a navigational mark takes to complete one cycle.
  • Pile: A strong timber driven into the ground in order to provide a boat berth. Normally set in pairs.
  • Pinch: To attempt to sail so close to the wind that boat speed is reduced.
  • Piston hanks: These are the metal fittings for attaching a headsail to the forestay.
  • Plot: To transfer a position to the chart.
  • Pooped: A dangerous condition where a following sea breaks over the stern of the boat.
  • Port: The left-hand side of the boat when looking forward.
  • Port tack: A point of sailing with the mainsail filled on the starboard side and the wind coming from the port side.
  • Position line: A line drawn on the chart giving 1 component of a fix.
  • Preventer: A line rigged to secure the boom and prevent an accidental gybe.
  • Pulpit: It's the metal frame round the bow at deck level, to protect the working crew.
  • Pushpit: It's the metal frame across the stern at deck level, to protect the working crew.


  • Range of tide: The difference between water heights at High Water and Low Water.
  • Reach: A point of sailing between close hauled and running free.
  • Reef: To reduce the area of a sail.
  • Registered tonnage: A measure of the volume of the vessel, not the weight. Originally used for taxation purposes.
  • Relative wind: This is the wind you feel. It's the result of true wind and boat movement.
  • Rhumb line: A line that crosses each meridian of latitude at a constant angle on a Mercator chart. It's not the shortest route.
  • Riding turn: This occurs when the turns on a winch become crossed and then jam.
  • Running by the lee: When the wind is blowing from the same side of the boat as the mainsail. This is risky, because of the possibility of a gybe.

Go back to Boat Terminology Part III

Go further to Boat Terminology Part V

Return from Boat Terminology to Boating Skills and Seamanship

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