John Ericsson

John Ericsson

Propeller—Ericsson's propeller—still the main form of marine propulsion 150 years later—replaced the inefficient and vulnerable steam-driven oars and paddlewheels. He designed and built the Civil War ironclad Monitor, which fought the Confederate Merrimac at Hampton Roads in March 1862. Ericsson also developed a calorific engine designed to use solar energy. (1993)