Correction: as all MNAs, International Classes, etc. the RYA MAY submit proposals to the ISAF. It could refrain from submiting anything - and considering the "quality" of their submission, they actually should...

This may be of use: in ISAF's website I failed to find submitions from many MNAs that could specifically ask for multihulls. Most Caribean, Central American and South American countries have not presented submitions, as well as most Asian and African countries. Needless to say, those MNAs have less political weight.