Future Olympic Classes?

I think the 505 was a development from the 470, but the 470 looks like it's a smaller 505, so maybe that's what you're thinking about.

The 505 was designed about 50 years ago from the coronet design, this is a passage from the class website:

The development of the Class began at the IYRU trials in 1953, held at La Baule to find the "best possible two-man centerboarder", an 18 footer "Coronet" showed clearly superior to all her competitors.

That winter the Caneton Association, the most important small boat racing body in France, asked the designer of "Coronet", John Westell, if he could modify her to suit their needs. Reducing the overall length, lightening the hull and modifying it considerably, together with cutting the sail area to 14 sq. mtrs., produced a new design which retained the good features of the larger craft. By a remarkable far-sighted decision members of the Caneton Association, at their A.G.M. in Paris in January 1954, voted unanimously to adopt the new class. The Five-O-Five was born!

Most people get a bit scared of the 505 because its seen as a complicated boat to set up and sail.  When the 420 nationals were at Helensburgh, one of the sailors didn't think they were any good because they "are more rope than boat!".  They soon changed their mind when we cruised past them on a broad reach!

The main thing about the 505 is that the rig can be adjusted easily as you sail whereas most skiff have to either change settings ashore or change rigs completely.  Don't be put off, 505s are well behaved, forgiving boats which will give exceptional rewards when sailed well!