The American Civil War saw a number of innovations in naval warfare, including the first torpedo boats which carried spar torpedoes.

A spar torpedo is a weapon consisting of a bomb placed at the end of a long pole, or spar, and attached to a boat. The weapon is used by running the end of the spar into the enemy ship. Spar torpedoes were often equipped with a barbed spear at the end, so it would stick to wooden hulls. A fuse could then be used to detonate it. 

In 1861 President Lincoln instituted a naval blockade of all Southern ports along the Atlantic and gulf coast of The Confederate States of America. The South, lacking the means to construct a naval fleet capable of taking on the Union Navy and countering the blockade, developed the torpedo boats as their line of defense.

David Class torpedo boat shortly after Civil War.

The Torpedo Boats were small fast boats designed to attack the larger capital ships of the blockading fleet.

The CSS David was built as a private venture by T. Stoney at Charleston, South Carolina in 1863. The cigar-shaped boat carried an explosive charge on the end of a spar. It was designed to operate slightly submerged in the water resembling a submarine. However it was considered to be a surface vessel. Operating on dark nights, and using anthracite coal which burns without smoke, David was nearly as hard to see as a true submarine.

The name of the ship, David, came from the Bibles parable of David and Goliath. 

On the night of October 5, 1863, David, commanded by Lieutenant William T. Glassell, CSN, slipped down the Charleston Harbor to attack the ironclad steamer The USS New Ironsides.

USS New Ironsides

The torpedo boat approached undetected. Her spar torpedo detonated under the starboard quarter of the ironclad, throwing a high column of water which rained back upon the Confederate vessel and put out her boiler fires. With her engine dead, David hung under the starboard quarter of The New Ironsides while small arms fire from the Federal ship spattered the water around the torpedo boat. 

Believing that their vessel was sinking, Glassell and two others abandoned her; the pilot, Walker Cannon, who could not swim, remained on board. A short time later, Assistant Engineer J. H. Tomb swam back to the craft and climbed on board. Reigniting the fires, Tomb succeeded in getting David’s engine working again, and the torpedo boat steamed up the channel to safety.

New Ironsides, though not sunk, was seriously damaged by the explosion.

The CSS Squib and CSS Scorpion represented another class of Confederate torpedo boats.

In 1864, the Union Naval Lieutenant Cushing fitted a steam launch with a spar torpedo to attack the Confederate ironclad CSS Albermarle.

Also, during this year, the Union launched the USS Spuyten Duyvil, a vessel with a number of technical innovations including an extensible and reloadable torpedo placement spar.

SS Spuyten Duyvil Engineering Plans

PT-Boats Official Site, US Torpedo Boats, Part 2: United States Patrol Torpedo Boat 109