How to Measure Sails

Measuring Mainsails

• 1). Attach a long tape measure to the main halyard and hoist it to the maximum height you would like the sail to hit. If you have a sail, hoist the sail until it's fully extended.
  
  
• 2). Measure to the mast bands and then to the top of the boom's surface.
  
  
• 3). Move the tape measure to the aft end of the boom and measure to where you want the clew ring to hit.
  
  
• 4). Lower the tape measure and attach it to the out haul line.
  
  
• 5). Pull the out line to the maximum point of draw and measure from that point to the aft face of the mast.
  
  

Measuring the Headsails

• 1). Attach the tape measure to the jib halyard and hoist the jib halyard until it reaches the top. Measure to where you will attach the sail's tack.
  
  
• 2). Measure the distance horizontally between the tack fitting and the mast.
  
  
• 3). Attach the tape measure to the upper furling and hoist.
  
  
• 4). Measure down to the tack fitting on the furling drum.