Trio was an historic 20 ft (6.1 m) trimaran sailboat derived from design by Lock Crowther and built by Howard Stephenson[1] in 1962 using the hull of an Austral 20.[1][2][3]
Meanwhile, Lockie's larger tri, which he named Kraken, was performing well on the Gippsland Lakes. Admittedly the only competition came from Lightweight Sharpies and Flying Dutchmen, so it was hard to gain a comparison with other similar boats — C-Class catamarans, for instance. In due course I finished my boat. It should have been up with his, at least in light airs but, partly because of my inexperience, my Trio was hardly ever a match for the bigger tri. There was one occasion when Trio beat them all, Kraken included: one of the Gippsland Lakes Yacht Club's annual long-distance races. The course was set from the yacht club at Paynesville, south-west along Lake Victoria to Waddy Point and return, a round-trip of about 15 nautical miles. As there was a gentle south-easterly sea-breeze that day, the course was virtually two long reaches, with no tacking and just a gybe at Waddy Point. We won easily, in record time.
— Howard Stephenson[1]
In Australia, Lock Crowther was focused on trimaran design, and after building and racing the original Bunyip in 1959, and designing a further two boats including Trio in 1962, Lock decided to build a C-class trimaran.