April 14, 1842 the new sidewheeler Medora was about to make a trial run for the builders and owners from Reeder's Wharf, where she was built, to North Point across Baltimore Harbor. The Baltimore & Norfolk Steam Packet Company, the ship's owners, and Charles Reeder, the builder, had invited a number of important people to join the ship for the first run across the harbor. The engine builder, John Watchman was also on board to demonstrate his new powerful engine and boiler.

Just after 3p.m. the Medora began to back away from the Reeder's wharf making only two revolutions of the engine when a powerful explosion blew away most of the upper deck and everyone who was standing on it. The funnels were blown high into the air and crashed down on the deck and the boiler, which had been the cause of the explosion, was thrown crosswise on the deck. The ship was enveloped in scalding steam, flying debris and dead and dying people who only moments before had been looking forward to a nice trip on a new ship.

The force of the explosion was so great that several people were catapulted from the upper deck to the shore, where some of them died. One man reportedly landed on the nearby steamer Constitution, where he died from his injuries. Captain Sutton, who had been standing on the upper deck just forward of the boiler was severely injured, the treasurer of the Baltimore & Norfolk Line was killed as was the line's agent and his son. The Medora settled on the bottom with the bodies of several people trapped inside.

At least twenty-seven people were killed or died of their injuries, some suffered for days before death came. Others carried the scars for the rest of their lives. What caused the boiler to explode was at first unknown, it was tested the day before at a higher pressure than would be normally used and was found to be satisfactory. It was later reported that one of the crew had tampered with the pressure valve so that the excess pressure would make a good showing of the speed and power of the boat.

The Mayor's office had asked for 100 men to come and help to clear the wreckage and remove the bodies and the wreck was finally raised and even repaired, she sailed under the name Herald until sometime in 1885.