For International One Meter (IOM) RC sailboats, the sail number rules are designed to ensure clarity and uniformity during races. Here are the key points:
1. **Font and Style**:
- Use a sans-serif font like Helvetica or Arial (or similar). Avoid thin or bold variations.
- Numbers and letters must be in the same color.
2. **Size and Spacing**:
- Sail numbers should be 100-110 mm in height.
- National letters should be 60-70 mm in height.
- The gap between adjacent characters (numbers or letters) should be 20-30 mm.
- Numbers on opposite sides of the sail must have a minimum gap of 60 mm.
3. **Placement**:
- Sail numbers are positioned below the class insignia, with a minimum distance of 60 mm.
- On the mainsail, numbers must be in the upper 75% of the sail.
- National letters are placed below the sail numbers.
4. **Additional Rules**:
- Only the last two digits of your sail number are displayed, but space must be left for a "1" in case of a conflict.
- On the jib, only the sail numbers are displayed.