Class Rules

IOM Class Rules 2013

(effective 1st March 2013).

Class rule change:

Emergency class rule change. (Valid from 18 September 2014): Based on proposal for  a change to IOM Class Rules to permit more than one topping lift  restraint line submitted by MYA acting as NCA for UK

Emergency class rule change. (Valid from 8 August 2014)

Class Rule Interpretations

IOM Measurement Forms 2014

(effective 1st March 2014)

2013  Certification Control Measurement Forms Cover

There have been changes in the forms to reflect rule changes which are noted in the following, but there is no change in the process.

Certification Measurement Form

With the changes in the class rules to allow pigmentation of resins used in the moulding of hulls and the difficulty in examining the interior of many hulls, the declarations required on the Certification Measurement Form have been modified to require the builder of the hull to declare that the materials used in the construction of the hull / boat are in compliance with the class rules. The simplest way to deal with the Declaration would be for the builder to include a pre-signed Certification Measurement form with the boat at delivery to the owner.  Alternately if a completed boat is not being delivered to provide a declaration that to the best of his knowledge the components supplied meet the requirements of the class rules. 

The Certification Measurement Form remains the only form required to be sent to and retained by a NCA as the result of a successful certification control measurement. The method of storage is the NCA’s decision

Additional Rigs Form

Should the boat be certificated with less than the full complement of rigs then the Additional Rigs Form may be used to add additional rigs to a certificate.  Once the certificate has been up dated then it need not be retained.

Check Lists

The two Check List forms are for the measurers use in conducting a certification measurement.  They are not required to be sent to the NCA.   As such, these check lists should be thought of as a work sheet of checks to be observed by the official measurer in a measurement only and if the boat complies with all the statements then there would be no further use for them.  The check lists might be of some use to the owner of a boat which failed measurement as a record of what has to be corrected before a certificate is issued.

Measurer’s record

This is not part of the Certification Measurement Forms but is only given as a suggestion of a means of a measurer recording measurements he, or she has completed.


 The term builderon the Certification Control Form is to be interpreted to mean the person who assembles the boat to sailing condition from its individual components. 

 The builder should then satisfy him, or herself, that the various components meet the current class rules.

 Where there is any doubt as to the component’s compliance, the builder should ask his supplier to provide a declaration certifying the component being supplied complies with the current class rules.  This should be available to the Official Measurer at certification control measurement.

 In the case of a hull the molder may wish to add a declaration for this purpose to his molder’s tag.

 Such a declaration should not be confused with the boat’s certificate resulting from measurement.

IOM Class Rules History