The Yearbook requires FlashPlayer to view correctly. 

If you are working in Google Chrome and do not have the Flash plugin installed, and activated in Chrome settings, it will open the mobile phone version instead.

Install Flash here: 

In Chrome, go to Settings > Advanced > Content Settings (in Privacy and Security) > Flash

Add to the Allowed sites:   

 If you have problems viewing the Yearbook clearly in other browsers, please contact Jenny at  

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.

logo twitter withbird 1000 allblue

Can't find the answer?

If you cannot find the answer to your question, please contact the RORC Rating Office
To report broken links on this site contact

Header images by:

John Crawley (CAN IRC)  
Jinno (c/o JPN IRC)
Back to top