Dennis - this note from Rod Johnstone from a
post about the Marblehead to Halifax race requirements. David Bows was on the organizing committee and even though the case for the J/30 was pleaded, it did not meet required stability requirements for that race.
The J/30 meets the requirements of (a) with a displacement of 3.2 tonnes displacement in IMS measurement trim (empty boat) which is well over the 3.0 tonnes requirement of OSR 3.04. I believe it would also meet the ISO requirement under the paragraph (b) as long as deck and cabin are included. I am copying this to Al J for him to confirm whether the J/30 meets this requirement and/or the RORC STIX of 32.