ILCA Sail Numbers and Letters

Jean-Luc Michon has put together some videos to help with placement of sail numbers and country letters for the ILCA 7 and ILCA 6 sails.

Style and Color

Only self-adhesive, stick on sail numbers and letters may be used. Each one shall be a single, solid color, and easy to read. The last four numbers on both sides of the sail shall be the same dark color, preferably black. The numbers in front of the last four shall all be another, obviously different color, preferably red. National letters are only required at international events, and shall all be the same color.


If the sail is not new, it should be sponged clean with mild soapy water, rinsed and dried. Find a large, clean, flat, hard surface to work on, such as a table or clean wooden floor.


Make a template that each number will just fit inside. See the Positioning Diagrams for the minimum sizes of numbers and letters, and template details. They are different for each of the Standard, Radial and 4.7 sails. The template is a rectangle for upright numbers, and a parallelogram for angled numbers.

Base Lines and Limit Lines

Use a pencil to lightly draw Base Lines and Limit Lines on the sail. The bottom of each number and letter must lie on a Base Line. The Limit Line is parallel to the leech of the sail, and 100mm from it. The closest letter or number to the leech is positioned to just touch the Limit Line. This is shown as the Start Point on the Positioning Diagrams. The number or letter should touch the Limit Line at the Base Line or at any other height, depending on its shape.

Starboard Side Numbers and National Letters

  1. Spread the sail out flat on the working surface so that the starboard side of the sail is facing up. The leech (back edge of the sail) will be on the left hand side as shown in the Positioning Diagrams.
  2. Make sure you are using the correct diagram for the design of sail you are applying the numbers to. Draw the Base Line and Limit Line for the starboard numbers (and letters) as shown on the positioning diagram.
  3. Before peeling off the backing, place the bottom of the first number on the Base Line, with the Start Point touching the Limit Line. Use the template with its bottom edge on the Base Line to make sure the number is at the correct angle. Pencil around the outline of the number.
  4. Peel and fold back about 10mm of the backing from the bottom of the number. Place the number within the pencil outline and press down to stick the peeled back area. Lift the remainder of the number and slowly peel off the backing as you smooth the number onto the sail, taking care to remove air bubbles and creases as you go.
  5. If the first number you applied was a 1 (one), measure from the bottom right corner of it and mark a point the space width away along the Base Line. The space width is 60mm for Standard and Radial rig sails, and 40mm for 4.7 sails – see the appropriate Positioning Diagram. Place your template on the Base Line with its lower left corner on the new mark and pencil round the outline of it. Before peeling off the backing of the second number, place it within the pencil outline of the template. Pencil around the outline of the number, and apply it as in point 4, above.
  6. If the first number you applied was not a 1 (one), place your template over it and make a pencil mark at the bottom right hand corner. Measure the space width from this mark along the Base Line and make a second pencil mark. Place the template, with its lower left hand corner on the second mark, pencil around the outline and then apply the next number as in point 4, above.
  7. When a 1 (one) is to be applied after another number, make sure the appropriate space width between numbers along the Base Line is maintained, as shown in the positioning diagram. Use the bottom right hand corner of the template, placed over the preceding number to find the start of the space width on the Base Line.
  8. Continue marking number positions using the template, the appropriate space widths between template corners, and applying numbers to complete the full sail number. Use the same method to apply national letters if they are required.

Port Side Numbers and National Letters

  1. Spread the sail out flat on the working surface so that the port side of the sail is facing up. The leech (back edge of the sail) will be on the right hand side. Draw the Base Line for the port numbers (and letters).
  2. Start with the letter or number closest to the leech making sure that no part of the number or letter crosses the 100mm Limit Line towards the leech. Follow the same method as for the starboard side of the sail, working along the Base Line away from the leech towards the luff.

Advice on Country Code Letters

Below are examples of letter forms that may be used and those that may NOT be used when specifying the country you are representing.

NOTE:  ISAF Rules of Sailing Appendix G1.2 specifies that national letters shall be clearly legible and of the same color.

= acceptable

 = not acceptable and will be rejected by measurers

d8     = constructed from a digital 8
d8*   = constructed from a digital 8 with additional leg added
font = arial narrow bold italic used here but other clear font is OK


Letters that cannot be constructed from digital eights are A, B, D, K, M, N, V, W, X, Y, Z