Rules Clarification for 10.3 Cunnigham:
10.3 Cunningham. Cunningham lines for both the jib and the main may be used. Cunningham lines shall use only the fittings supplied by the manufacturer. Line loops or knots may be added to any part of the line to provide additional purchase.
As supplied by the builder, a jib cunnigham may utilize thimbles or rings as part of the line loops as described in Rule 10.3.
Blocks, cleats, or hardware not associated with the line loops shall be deemed not legal to use in a jib cunningham system.
Please review the jib Cunningham if utilized on your boat to ensure this system meets Rule 10.3
C420 Class Measurer