Coulter -- The Missing Link -- January 19, 2022

San Francisco Call, 22-April-1895

William A Coulter did many maritime drawings for the San Francisco Call. Click on the image for a larger view. 

THE PROBLEM IS SOLVED

A Compound Engine Can Be

Run Economically With

One Valve.

TESTED ON A STEAM LAUNCH.

The Missing Link Is the Fastest

Little Craft of Its Kind

on the Bay.

"Can a compound engine be run with only one valve?" is a question that has engrossed the attention of engineers for over a generation. The overcoming of the difficulty meant the doing away with a steam chest and receiver, and a consequent saving in fuel, space and weight.

J. L. Bonner, master mechanic of the San Francisco and North Pacific Railroad Company, has solved the problem, and his launch "The Missing Link" is a practical illustration of the fact. The launch is one of the whaleboats of the old steam whaler Orca. It has not been altered in any way except to take out a thwart in order to make room for the engine, and to bore a hole in the stern to allow working room for the propeller shaft. That the experiment is a success is proven by the fact that with 200 pounds of coal on board and twenty-five passengers, the Missing Link can average ten knots an hour for forty-eight consecutive hours. On a run of one or two hours and with the steam kept at a pressure of 250 pounds, she can easily make thirteen knots an hour, and is consequently by far the fastest launch in the bay.

The Missing Link is thirty feet long and six feet beam. In the Custom-house she is registered three tons net, and is consequently the smallest steam vessel that has ever received a license from Uncle Sam. Her engines weigh exactly ninety-six pounds, and Engineer Bonner's son carried them from the machine shops to the whaleboat on his back. The boiler is about half the size of an ordinary cooking stove, and at first glance it seems ridiculous that steam sufficient to drive a thirty-foot boat thirteen knots an hour could be generated in such a small space. The fact is that every ounce of steam is used as it is made, and it only costs 15 cents an hour to run her. It would be almost impossible to burst the boiler, as it has stood a pressure of 1500 pounds to the square inch.

The engines and boilers were built by Messrs. J. L. Bonner and C. G. Ny during their spare moments. In talking about the matter yesterday Master Mechanic Bonner said: "My idea was to get something fast, machinery that was almost noiseless and a great saving in space and weight. In order to do this I had to construct a compound engine with a valve that would work the steam over twice, thus saving a steam chest and a receiver.

"There is only one valve in the launch instead of two, so therefore she is called the Missing Link. Anyone who can keep steam up and water in the boiler can run one of these boats, as the Missing Link is practically automatic. With seventeen gallons of water in her tank and 200 pounds of coal in her bunkers she will run for forty-eight hours and cover 500 miles. All her machinery is of the simplest kind, and her engines could be duplicated in twenty-four hours on a lathe. The appliance is much cheaper than a gasoline engine, much safer, and far greater speed can be obtained. The engine and boiler would be particularly useful in lifeboats on ships and also in whaleboats. A lifeboat with machinery in her similar to the Missing Link could tow half a dozen rafts and other ship's boats for days, while on a whaler it would be indispensable in towing whales to the ship and boats back after an unsuccessful hunt."