Why is the prefix ‘1’ before a sail number required only on the mainsail?

Events Rules Sail Identification 
Question Details

In Appendix E8 G.1.5 (b) (4) requires the prefix ‘1’ before a mainsail number only. Why?

Answer

This is a drafting error in the Appendix E rule E.8.

The following addition to the Standard Sailing Instructions used by IRSA Members for their events should be made.

SAILING INSTRUCTIONS

1.4  Racing rule E8 will be changed as follows:

Add new G.1.5 (a) (6) ‘with sufficient space in front of the sail number for a prefix ‘1’.’

Delete G.1.5 (b) (4).