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  • Writer's pictureGordon Thorsby

The Sinking of Patapsco, Charleston Harbor

by Gordon Thorsby

Passaic Class monitor

January 15, 1865

From Rear Admiral John A. Dahlgren

Sir: I regret to inform the Department of the destruction of the U.S. Monitor Patapsco by a torpedo last night about 8 o’clock (actually 8:10 PM) near the south entrance to the lower harbor of Charleston.

The Patapsco, a Passaic class monitor, named after a Maryland river, was launched September 27, 1862. The monitor stood out from the other monitors with its red band around the top of her smokestack. She joined the South Atlantic squadron in March, 1863, and on April 7, joined in the reduction of Fort Sumter and Fort Wagner. The Patapsco took a pounding receiving 47 hits from various gun positions in the harbor. In February and later in November, 1864, it captured and destroyed several sailing vessels in the Wilmington River in Northern Georgia. Its commander at the time was Lt. Commander S.P. Quackenbush and executive officer was William T. Sampson (of later Spanish-America War note.) The Patapsco was rigged with a counter-mine device that had recently been designed by John Ericsson.

In December, of 1864, Gen. Sherman, who was in Savannah, wanted the squadron to ”cooperate” and make demonstrations to distract Confederate forces in the Carolinas into expecting that Sherman was headed to Charleston. Rear Admiral John A. Dahlgren put those demonstrations into action. Sherman’s moves were to begin around January 15th. Four Monitors were to operate near Confederate shore batteries but commanders of the ironclads wanted efforts to clear possible torpedoes in the harbor and operations were planned with "tugs, boats, with hawsers and grapnels." The orders on 12/31 were to "observe and disturb all attempts to place torpedoes" in the harbor.

These craft went out after dark on the 15th with ironclads Patapsco and Lehigh close by as

picket monitors and with Patapsco closest in. Quackenbush stopped Patapsco’s engines to drift in with the tide and six to seven boats trolling about her seeking mines. They were 800 yards off of Fort Sumter and 1200 yards off of Ft. Moultrie.

Boat crews were finding mines and removing other obstructions and were ordered to stay within 100-200 yards of the Patapsco. There was considerable concern about being observed by guns on shore.

While approaching a buoy indicating shallow water, there was a sudden explosion on her port side, a cloud of smoke and within 30 seconds, Patapsco’s deck was already under the surface. The ward room with three officers went up in the explosion along with 10 feet of deck. In his report, Quackenbush reported, “In an instant more, I discovered that the whole forward part of the vessel was submerged and, there being no possible chance to save the vessel, I gave the order to man the the boats. “ In yet a couple more minutes, the deck was submerged to the turret. Quackenbush was able to personally save eleven of the crew. Witnesses claimed that the main ladder to the deck was also blown off its dislodged and why so many became trapped. Quackenbush and Sampson were atop of the turret looking for shallows when the explosion occurred. Pumps were immediately ordered and boats ordered but within a minute, it was realized that no effort could save the ship. Lehigh had just raised anchor went it heard voices in the water and lowered boats to rescue men." To a man on deck of a distant ship, all was quiet until there came a loud report and a flash in the darkness in the direction of Ft. Sumter.

Map by Tommy Tramp

An inquiry was launched per standard procedure and it was determined that the torpedo exploded 35 feet from the stem, severely damaging the ironclad and it sank almost immediately. It was amazing that as many men survived as they did. Sherman was notified of the loss and he sent back a letter of regret to Rear-Admiral Dahlgren.

Five officers and 38 men were able to climb out and jump in boats or the harbor. Sixty-two souls went down. Only those on deck, a few in the turret, and in a couple of other spaces were men able to escape. The Patapsco went down by the bow and rested on the bottom of the harbor where she joined several other vessels lost during the war. She is there still.

Along with it, John Ericsson’s invention went down as well.

Note: officers in the picture are of Onandaga.


1 Naval History and Heritage Command, August 19, 2015

photo courtesy of via Tommy Tramp. Location of Patapsco in Charleston Harbor.

Official records, Union and Confederate Navies War of the Rebellion, Volume 16, pages 170-181.

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