Smithsonian museums continue to be closed to support the effort to contain the spread of COVID-19. Read a message from our director, and check our website and social media for updates.

Plunger Propulsion, Patent Model

Plunger Propulsion, Patent Model

This patent model accompanied Jacob Eckhardt’s application for a new method in the propulsion of vessels that received patent number 179,407 on July 4, 1876. The model comprises a black-painted hull enclosing an internal mechanism of rods and gears. The bottom of the hull is wood; the sides are metal. The model represents a system for propelling vessels though water using oscillating plungers. Eckhardt’s plan was to propel a steamship by the action of oscillating plungers. Pairs of plungers were to be placed in recesses built into a ship’s hull. By positioning two plunger boxes at each end of the vessel, and by making the vessel pointed at both ends, Eckhardt claimed that the ship would “be able to run in either direction without turning around.”
Currently not on view
Object Name
Patent Model, Propelling Vessels
Object Type
Patent Model
Date made
patent date
Eckhardt, Jacob
Associated Place
United States: Missouri, Saint Louis
Physical Description
wood (overall material)
metal (part material)
overall: 12 1/8 in x 5 1/8 in x 4 1/2 in; 30.7975 cm x 13.0175 cm x 11.43 cm
ID Number
catalog number
accession number
patent number
Credit Line
Gift of Arthur E. Denu
Patent Models
See more items in
Work and Industry: Maritime
America on the Move
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object