Born in Baltimore, Maryland, Hammann attended Baltimore Polytechnic Institute, and joined the Naval Reserve in October 1917.
He was awarded the Medal of Honor, when, as a pilot of a Macchi M.5 seaplane on August 21, 1918, off the Austro-Hungarian coast, he dived down and landed next to a downed fellow pilot, George M. Ludlow, and brought him aboard, and although his plane was not designed for the double load, brought him to safety amid constant danger of attack by Austrian planes.
An enlisted pilot at the time, he was commissioned as an ensign in October 1918.

Hammann was killed while on active duty at Langley Field, Virginia, June 14, 1919.
Born in Baltimore, Maryland, Hammann attended Baltimore Polytechnic Institute, and joined the Naval Reserve in October 1917. He was awarded the Medal of Honor, when, as a pilot of a Macchi M.5 seaplane on August 21, 1918, off the Austro-Hungarian coast, he dived down and landed next to a downed fellow pilot, George M. Ludlow, and brought him aboard, and although his plane was not designed for the double load, brought him to safety amid constant danger of attack by Austrian planes. An enlisted pilot at the time, he was commissioned as an ensign in October 1918.
Hammann was killed while on active duty at Langley Field, Virginia, June 14, 1919.
Charles Hammann