John
Ericsson invented the caloric (heat)
engine, as well as a steam condensor that allowed
a steamer to produce fresh water while at sea. He
is best remembered, however, as being the
designer and builder of the USS Monitor,
a unique ironclad ship that incorporated many
elements still used in warship designs today.
John Philip
Holland launched his first
successful submarine in 1881. The company he
founded ultimately became the Electric Boat
Company, which has subsequently built the vast
majority of the U.S. Navy's submarines, as well
as submarines for many other nations.