Sails 
Sails are measured completely in accordance with the WS Equipment Rules of Sailing (ERS). Sails shall be dry when measured, and on a flat surface with just sufficient tension to remove any wrinkles across the line of the measurement being taken. The following type of sails can be measured:


The maximum number of sails allowed on board while racing (not including storm and heavy weather sails required by the WS Offshore Special regulations) is defined by the ORC Rating Rule 206 as follows:  


Headsails include those set on the forestay and headsails set flying.  
Spinnakers include symmetric and asymmetric.  
Mainsail and Mizzen 



Headsails 



Headsail measurements are similar to those of the mainsail, including the top width (HHB) as well as four widths found on the leach between head and the clew: at 1/4 (HQW), 1/2 (HHW), 3/4 (HTW) and 7/8 (HUW) leech heights. Points on the leech are found by folding the sail to find equal distances between clew and head or between two adjacent measurement points. Additional measurements for headsails are: luff length (HLU) and luff perpendicular (HLP) as the shortest distance from the clew point to the luff. Headsail area is then calculated as follows: 



When the leech has a clear hollow and the headsail is not the largest in the sails inventory, measurements can be reduced to HLU and HLP only.  
 
Spinnakers: Symmetric and Asymmetric 







Mizzen staysail 

Mizzen staysails shall be threecornered. The longest side edge shall be taken as a luff, the shortest edge shall be taken as a foot, and third edge shall be taken as a leech. Mizzen staysail measurements include: YSHF as the shortest distance that can be measured from head to foot, YSHW as the half width or distance between midpoints on the luff and leech, and YSFL as the foot width. 

Mainsail 
Headsails on the forestay 
Headsail set flying 
Spinnakers 