ISORA dual scores racing using IRC and ECHO
ECHO is a performance based handicapping system administered by the Irish Sailing Association (ISA), the governing Body for the Sport of Boating in Ireland.
ECHO can be very simply summed up as a system that ranks boats in any fleet from fastest to slowest [or vice versa] and handicaps them accordingly. A boat with a higher average speed should always have a higher handicap than a boat with a lower average speed, or, which is the same thing, a boat should not have a lower handicap than a boat that regularly finishes behind it - on the water.
This principle is explained in greater detail in the document here. It answers the basic questions about the nature of ECHO and also explains the difference in approach between ECHO and IRC.
ISORA Chairman, Peter Ryan, explained that 'ECHO compliments the ISORA ethos of running many race results out of the same race. All boats will be dual-scored under IRC and ECHO'