Because wind speed is squared, it is the most important variable and can greatly influence loading. Wind speed (the apparent wind) should be calculated for the specific sail being analyzed. For example, the #1 genoa on a 25' (7 m) boat might only be carried in 15 knots of wind while the #3 blade on a Maxi-boat could well be carried in 40 knots.

To calculate loading on a genoa lead car, multiple sheet load by the load factor of the sheet. Most #1 genoas will deflect about 45° while a #3 genoa may deflect 75° or more.

Lead car adjuster tackle load is dependent on the angle of deflection of the sheet in the lead car, but is generally assumed to be .3 of lead car load when deflection is 45° and .5 of lead car load when deflection is 60°.