Farrelly's stringerless boards were noticeably lighter and more flexible. The result was a lively ride that foreshadowed the downsizing that occurred a few years later.
It was a real improvement, and a number of manufacturers in Australia and the US developed stringerless boards for their model line prior to the shortboard revolution.
Gordon and Smith, USA
Here's a shot of the best contest surfers in Australia at Bells, early in 1967. Midget is on the far right, with a stringerless. Nat Young, second from the right, is with his followup board to 'Magic Sam,' which was lost in California some months earlier...
You can see a Greenough fin on Nat's longer, stringered board, while Midget's stringerless sports a less sophisticated contest/pivot fin. They were each heading the right direction, but neither had it all together yet.
Taken to the extreme, stringerless boards during the end of the longboard era approached Greenough's level of flex...