Info on IRC 2011 TCC Changes

You may have noted that your (or a competitor’s) IRC TCC has changed significantly between 2010 and 2011. For 2011, there have been a number of changes to IRC calculation of rating. Because of the confidential nature of IRC, we cannot provide detail of these. We can however note that the change will be related to one of or a combination of the following:

Age Allowance

Age Allowance is automatically applied to all boats and is incremented every year. There is however a maximum age allowance. Once a boat has reached this age, she receives no more benefit.

Keels

The treatment of low CG keels has changed. In most cases, this will result in a small reduction in TCC, although for a few designs, a small increase will result.

Light Racing Boats

Evidence from race results around the world has demonstrated that small to medium size (30’ – 45’) ‘race’ boats have been disadvantaged while larger (> 50’) race boats have been slightly advantaged. A change has been made to the calculation in TCC for these boats resulting in a small decrease in TCC for the small to medium size boats and a small increase for the larger boats to redress the balance without changing the overall IRC philosophy and objectives.

Moveable Ballast

A change has been implemented to more equitably treat moveable ballast (canting keel) boats. Some of these will see a small reduction in TCC.

Hull Factor

Some detail changes have been made to the assessment of Hull Factor. These will not affect many boats and may result in either increases or decreases in TCC dependant on the boat.

Carbon Masts and Composite Standing Rigging

The IRC treatment of both of these features has changed resulting in small reductions in TCC.

Rig Factor

Rig Factor now includes the effect of an adjustable mast foot or forestay. The small number of boats with these features will therefore see a change in Rig Factor. This is however solely an internal change with the effect on TCC unchanged.

Additionally, Rig Factor is now rounded to 3 decimal places as compared with the previous 2 places. This will have a small effect, which may be an increase or a decrease, for many boats.