A splendid plan published in Modern Mechanix in July 1931 
Build This Monorail Bathing Chute for Thrills
As a thrill producer, it will be hard to beat this monorail bathing chute. Erected on a hill sloping down to a beach, it will send you flying out into the water at a breathtaking speed. Construction is very simple.
BATHING weather prompts many novel means of sport in the water such as diving slides, swings, etc., but here is a regular “shoot the chute” in simplified form with which loads of sport can be obtained and all at a minimum cost.
In laying out plans for the chute try and find a spot of land with a long gradual dip towards the bathing beach or swimming hole. Several hundred feet will furnish the greatest amount of fun, but it should have a hundred-foot stretch at least.
The track can be constructed entirely of ordinary hemlock or spruce boards six inches wide and 7/8 inches thick. The accompanying sketches show just how to put it together. Use short lengths of board laid end to end, the joints meeting over posts sunk into the ground at the proper height to give the track a nice even bearing to the slider.
Plans and description in jpg HERE
Found at: blog.modernmechanix.com
Retrorambling 