The IRC certificate includes a DLR number (Displacement/Length Ratio) which is sometimes used to help determine class splits, for instance between racers and cruiser/racers.   DLR is calculated as follows:

DLR = (27.87 * IRC Displacement) / LWP^3      (Help with mathematical formulae)


a) LWP = LOA – BO – SO
b) IRC Displacement is directly related to the Boat Weight on the certificate. Therefore any change to Boat Weight will be reflected by a change in IRC Displacement.
c) The calculated value of DLR is rounded to the nearest integer value for printing on each boat’s certificate with 0.5 rounding upwards.

 *NOTE* IRC Displacement is an internally calculated figure and is NOT the Boat Weight on the certificate.