Other IOR boats.
Ranger 28, very different from the earlier Ranger 29 - both by Gary Mull. This is an IOR-type half-ton hull.
I don't find this to be a grossly distorted hull shape. The rudder is on a substantial skeg, which might affect its efficiency but also adds strength. Note that the Mull designed Ranger 28 is NOT the same thing at all, at all as the Philip Rhodes designed boat of the same name.
Typical early IOR-type transom a la Doug Peterson, though this is a San Juan 28, not designed by him. Note that a Hawkfarms butt looks a lot like this.
Nelson-Marek 36..
This is a Farr 727, one of Bruce Farrs most successful designs. It's an IOR quarter-tonner, though an early one, and not at all what I'd call "distorted". There's still a strong 727 association in New Zealand. 727's won the quarter-ton worlds for a couple of years until some more specialized designs came along.
CCA boats
Bristol 29
Pearson Renegade (always liked these.....one of the first split-underboady sailboats)
IMS boat... see how "squared off" the stern is?