Early IOR quirks
When you ask about early IOR boat quirks, the small mainsail and large headsail sail plan shows up at the end of the CCA era and gets extreme by the earliest IOR boats, (look at a Tartan 41, Northstar 500, Ranger 37, Morgan 27 or Morgan One Tonner). The pinched ends and tumble home topsides show up very early as well and these lead to the wild rolling downwind rides that made these early IOR boats known thier "hold onto your hats she''s going again" broaches and round ups. The full topsides and pinched bow sections meant that as they heel, these early IOR boats tend to go bow down and aerate their rudders. IOR boats tended to be underballasted right from day one and to have comparatively high vertical centers of gravity. While some like the Tartan 41 remain as pretty reasonable boats most are pretty useless as race boats or cruisers.