I was a member of the Greater Wellington Marine Model Club. One pond on which we sometimes sailed had quite a large ramp/beach at one end.
Another member of the club had made
a model of an amphibious vehicle, which he successfully manoeuvred into and out of the water.
Some time later we moved as a family to Christchurch and I was introduced to the Christchurch Society of Model and Experimental
Engineers. At that time they occupied land in Addington which included a 5” raised model train track which encircled a boating pond. And YES it had a well formed ramp going down into the water. This was normally used for the launching of large boats
At the suggestion of our youngest son, I started to investigate the practicalities of building our own DUKW.