He saw active combat while serving aboard three ships, most notably as commander of the USS Essex from 1863 to 1864, an ironclad gunship on the Mississippi River.

Captain Townsend died of heatstroke while commanding the USS Wachusett in China in 1866, and is buried in Albany, New York.

His father was an executive of the Stirling Iron Works, which under his great-grandfather Peter Townsend forged The Great Chain which was strung across the Hudson River at West Point and prevented the British Royal Navy from threatening that important American base and potentially controlling the river.

Townsend entered the United States Navy on August 4, 1837, serving first as a midshipman on the ship John Adams.

At the beginning of the civil war Townsend re-entered the service on 17 September 1861 as acting-lieutenant, receiving a promotion to commander a few months later, and served on a number of fighting ships.

The Miami was a side-wheel, double-ender gunboat with a crew of 134 and armament of one 80-pounder Parrott rifle, one 9 inch smoothbore, and four 24-pounder cannon.

The ship participated under Admiral David Farragut as part of the Mortar Flotilla in neutralizing Confederate forts below New Orleans.

She was a large (1,032-ton) steam sloop-of-war that served the United States Navy in the American Civil War.

The executive officer John Woodward (Jack) Philip, (later Admiral), assumed command of the Wachusett and sailed it downriver with the goal of making it to Japan for the health of the crew.