News IMA ATO statement on water ballast for 2024 season

IMA ATO statement on water ballast for 2024 season

London, 10 November 2023

Dear All,

 With the increased interest in using variable ballast (water ballast) systems within the maxi fleet, we feel that it is important that all understand the measurement requirements we will apply at IMA events in this context.

Please note that IRC rule 22.3.1 states “any such system shall be permanently installed and declared …” and also that RRS 51 is modified by IRC.

IRC Rule 22.3.2 goes on to note that list angle is measured with ballast tanks fully filled on one side.

IRC Rule 22.3.3 explicitly notes that “….the maximum list angle and the maximum volume of water, including plumbing that can be carried on each side of the boat shall be declared.”

To ensure full compliance with these rules at IMA events, in a manner that is realistically controllable, the IMA ATO intends to purchase a calibrated flowmeter for use during equipment inspection, where considered appropriate. This shall be used to confirm that the full capacity of any and all variable ballast tanks is applied to the IRC certificates with regards to variable ballast maximum volume and list angle.

Where there are multiple tanks and/or pumping arrangements used to alter the fore and aft location of variable ballast, this shall not alter IRC rules, and the full capacity on each side shall be considered as maximum volume and list angle shall be measured with ALL such tanks completely filled.

Only sealing arrangements that permanently disable the system in a manner that is approved in writing by the ATO shall be considered if such systems are to be declared as non-functional for an IRC declaration.

James Dadd


International Maxi Association
Legal Headquarters: c/o BfB Société Fiduciaire Bourquin frères et Béran SA - 26, Rue de la Corraterie - 1204 Genève - Switzerland