Early IOR quirks
The Contessa 32 is an RORC design(Royal Offshore Racing Conference). The RORC was an earlier racing rule than the IOR. The IOR was developed by a joint international committee as an attempt to merge the RORC with the CCA rules. The Yankee 30 was a very late CCA rule design with minor changes that recognized the likely impact of the IOR rule. That makes sense since Olin Stephens was on the IOR committee and he also designed the Yankee and so knew what was coming. The Tartan 30 was a MORC design which produced much more powerful and well mannered hull forms and rigs.