S.S. Beaver
This information has been taken from the book called:
"S.S. Beaver: The ship that saved the West" by Derek Pethick(copyright - 1970).
The ship, rated at 109 tons, was 100'9" long and 20 feet wide (or 33 feet, including the paddle-boxes); the depth of its hold was 11 feet, and its draught when loaded was about eight and a half feet. The paddle-wheels were thirteen feet in diameter, with paddles six and a half feet long which revolved, when at top speed, at thirty times a minute. It had two masts and a single tall funnel, while only a small bridge rose above the gunwale.
On June 25, 1835, it's fitting out completed, the Beaver went for a trial cruise in the English channel. All went well, and the engines were then dismantled and the paddlewheels unhipped, as it had been decided that the actual journey to the Pacific coast should be made by sail and not entrusted to the new method of propulsion.
Another vessel the barque "Columbia" was was being built for the Company, and it was intended that the "Beaver" and the "Columbia" travel to the Pacific in company, and accordingly the two vessels left Gravesend on August 27, 1835. They anchored safely at Fort Vancouver(Vancouver, Washington) on April 10, 1836.
Little time, however, was wasted in celebrating the achievement of the voyage. The installation of the Beaver's enginers and paddle-wheels began at once, and on May 16th at 4 p.m. the engineer's got the steam up and tried the engines.
The novelty of a steamboat on the Columbia River awakened a train of prospective reflections upon the probable changes which would take place in these remote regions in a very few years.