I don't know anything about the old IOR classes, but if you know the name and model of your boat, perhaps the Sail Calculator page
will tell you the specs you want. Be sure to look the entire page over as there are several approaches embedded in it.
Thanks, It's an interesting link. It does not list my boat (I did not really expect it to) so all I could was pick a design that had some specs like mine (that I knew) and see what came up.
The original owner/builder must have had some degree of confidence in his boat as I have it on record he sailed it out in Bass strait on more then one occasion.
I know it will simply and safely round up if overpowered in a gust.
I've been out in 4-5 metre swell, seemed to handle it fine although not something I'd look to do every day.
Obviously I'm not planning on passage making in this boat but it's still of interest to me to know it's history and to get as much data on the design as I can. I'm comfortable with it's ability as a coastal cruiser.
It's heavier rigged then some comparable sized boats I've seen, dual swept spreaders, solid glass in hull and deck.
The designer was very well known in Australia and as I understand it even had experience in America Cup boats.