Innovative World.
The Donkey Steam Engine, Part Two – The Loggers Best Friend
May 11, 2021 Comments..0

The logging industry was pushed to the limit in 1881 by the exploding demand for lumber. The forests in Maine were logged out and had been abandoned. As timber in the Great Lakes region was becoming depleted, and as the logging companies moved west, the guys in the forest were pushed harder and harder for more, more, and more; the industry struggled to keep up.

As so often happens throughout history, about the time a machine is greatly needed it, someone invents it. When the logging industry was desperately trying to dramatically increase production, along came an invention that revolutionized that industry. That invention was the Donkey Steam Engine – a steam-powered mechanical winch developed by John Dolbeer in 1881. That year was generally declared as the beginning of technological change in the industry. This machine was both the loggers best friend and his deadly enemy if he wasn’t constantly on guard. As one logger said, “There’s lots of hard work out there but if you don’t look out it’ll kill ya.”

John was a founding partner of the Dolbeer and Carson Lumber Company in Eureka, California. Eureka is a town in Humboldt County about 100 miles from the California-Oregon border and is a huge logging and lumbering area.

Dolbeer received patent number 256553 for the Donkey Steam Engine on April 18, 1882. By comparison, to date 7.5 million patents have been issued in the United States. As a point of interest, the current patent numbering system began with a patent #1 issued on July 13, 1836. No information is available about that patent but prior to that date, about 10,000 patents had been issued.

The Steam Donkeys actually acquired their name from their origin in sailing ships, where the “donkey” engine was typically a small secondary engine used to load and unload cargo, raise the larger sails with small crews, or to power pumps. Dolbeer had been a naval engineer before turning to logging which undoubtedly led to his choice of the name for his invention. It is also said that loggers gave it that humble name because the original model looked too puny to be rated in horsepower. Donkey power doesn’t have quite the image of a powerful engine, but as you will see, a Donkey Steam Engine could readily snatch a giant log out of the forest.

This wonderful engine was essentially a collection of mechanical components starting with a wood-fired steam boiler. The boiler supplied steam at anywhere from 100 to 200 PSI to a one cylinder engine that transmitted power through a connecting rod to a crank shaft on which was mounted a flywheel with some sort of brake mechanism. A lever operated clutch configuration controlled a complex of reduction gears and drive wheels that drove a winch. The winch could be either a large pulley with a horizontal shaft or a drum, or a capstan, mounted on a vertical shaft.

The Donkey Engines came in an endless variety of configurations of steam, gas, diesel, or electric power plants plus drums to hold wire rope. They had one thing in common; all were engine model used to haul logs from the woods, load them at landings, move equipment, rig up trees, and to lower or raise wagons up and down inclines. But, the vast majority were steam-powered and most were built in the Seattle, Tacoma and Portland, area. Hard to imagine now but a hundred and fifty years ago Seattle was basically a logging town, as was Vancouver, British Columbia.

In the simplest setup, a “line horse” would drag a cable out to a log in the woods. The cable would be attached, and, on a signal from the whistle on the engine, the Donkey’s operator would open the steam valve on the boiler and engage the clutch, allowing the transmission mechanism to rotate the drum. As the cable was wound around the drum, the log was dragged to the Donkey. The log was then taken either to a mill or to a “landing” where it would be transferred for onward shipment by rail, road or river; either loaded onto boats or floated downstream directly in the water. The layout of a logging operation was no small task as terrain and river characteristics had to be carefully considered and were crucial to the successful movement of these giant logs.

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