Ericsson’s Patent Model of a Marine Steam Engine – ca 1858


This model was filed with the application to the U.S. Patent Office for Patent Number 20,782 issued to John Ericsson of New York, New York on July 6, 1858. The patent was for improvements in marine steam engines for powering a screw propeller. Mr. Ericsson’s goal was to maximize the power and compactness of the engine so that it could be located transversely and very low within a boat.

His design consisted of two compact steam cylinders which were bolted together and mounted horizontally across the beam of the ship. They drove a single propeller shaft via a system of push rods and rocker arms. The design allowed for even application of power with reduced vibration and wear on engine parts and the frame of the ship.

Mr. Ericsson was a prolific inventor; his inventions included many types of steam engines and associated apparatus as well as air engines. He was the designer of the USS Monitor for the North during the Civil War, and the engine for the Monitor was based on this patent.

The patent model is made of brass and is mounted on a wood base representing a section of the hull of a ship. A brass plate on the base of the model is engraved “Screw Propeller Engine, J. Ericsson, Inventor.” All of the key elements of the patent are illustrated by the model which was provided with a crank on the propeller shaft to allow operation for demonstration. A full description of the operation of the engine along with complete diagrams can be found in the patent document online at the United States Patent and Trademark Office website,

Date Made: 1858Patent Date: 1858-07-06

Inventor: Ericsson, John

Place Made: United States: New York, New York CityAssociated Place: United States: New York, New York City

Subject: Patent ModelsSteam EnginesSteamships


See more items in: Work and Industry: Mechanical and Civil Engineering, Engineering, Building, and Architecture, Patent Models

Exhibition: Power Machinery

Exhibition Location: National Museum of American History

Related Publication: Frank A. Taylor. Catalog of the Mechanical Collections of the Division of Engineering United States National Museum, Bulletin 173

Data Source: National Museum of American History

Id Number: MC.251295Catalog Number: 251295Patent Number: 20,782Accession Number: 48865

Object Name: engine, steam, marine, modelpatent model, engine, steam

Measurements: overall: 9 in x 11 1/2 in x 11 1/2 in; 22.86 cm x 29.21 cm x 29.21 cm


Record Id: nmah_846160

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