There is a + or – 0.1 kg* tolerance on my boat’s (6M or A Class) certificated weight. Can I add 100 grams of equipment without getting it re-measured? * 50 grams for the Ten Rater

No. In order to get a certificate for your boat** you have signed the measurement form or certificate form to declare you will race the boat only if you maintain it in compliance with the class rules and that alternations or repairs to equipment that are required to be measured will be checked by a measurer before use (or words to that effect depending on the class).

**           If you are a second or subsequent owner of a boat and have a valid certificate you will have signed the owner transfer section of the certificate which also contains a declaration to the same effect.

You may replace items like for like without any problem but any change in weight, or movement of weight, is bound to change the waterline length and other measurements.

The reason for the tolerance is to permit a broader range of weighing equipment to be valid for use both at initial certification and subsequent equipment inspection.