I am new to sailing and have noticed that nearly all the boats at our local sailing club have nubers on the sails. What is this for and what does it mean?
If it is from the Builder / Manufacturer, then generally it is build number or consecutive number.
If it is not from builder, then it is most likely a Racing K number or could possibly be a Class Association issue.
Most boats show the builders designated number ..... example :
My fathers Snapdragon was : SD 9 ..... which equated to the 9th Snapdragon 23 built at Thames Plastics ......