While going through some old pictures of mine I found some from early 1981 (28 years ago), It is the "Rickshaw" the width overall is 1m.
Using 20" bike wheels and a 3 sqm sail it sailed VERY well and was light due to the Aluminium tube construction. The yacht was built in the loungeroom of the upstairs flat I was renting at the time. It performed well in a championship held at Mallala Motor Racing circuit later that year, as you could get up to full speed and tack across the width of the race track.
The "Sandpiper" yachts were based on what was learnt from the "Rickshaw"

The yacht was based on a pic I saw years earlier in landsailing book.