These notes are in addition to the Frequently Asked Questions (also shown in the IRC yearbook).

IRC is a self-measurement system.  There is no requirement either to have your boat officially measured or weighed unless you want to, your IRC Rule Authority requires it, or you need an Endorsed certificate.

Generally, acceptable sources of data are as follows.

 E* denotes acceptable for Endorsed certificate

Linear measurements (hull, rig) :

E* Official measurement by an authorised measurer

E* IMS or ORCi measured data

E* One-design data for approved IRC one-design classes

Owner or representative measurement

Designer or builder data *

Class standard hull data

 Linear measurements (sails) :

E* Official measurement by an authorised measurer

E* Measurements supplied by an authorised sail measurer

Owner or representative measurement

Weight:

E* Weighing on an approved single point loadcell, verified by an authorised measurer

E* Weighing on approved pressure pads, verified by an authorised measurer

E* Weight calculated by flotation measured by an authorised measurer (see separate paper PDF)

E* One-design data for approved IRC one-design classes

E* Light class standard weight for established production designs

Class standard weight or sistership weighed data

Weight derived from IMS or ORCi or other rating certificate. (E* at the discretion of the Rule Authority)

Weighing on weighbridge is usually accepted unless we believe it to be in error

Designed weight, or derived from designed sailing displacement *

The following are NOT acceptable :

Registered Tonnage

Weighing on built in loadcell of crane

Weighing on travel hoist

 * Data from a sales brochure is usually acceptable, but we reserve the right to use different data where we believe it to be more accurate.

Please contact us if you wish to arrange measurement or weighing by an approved measurer.