James Marshall commanded the New Era, a Union gunboat, during the American Civil War. Marshall was in command at the Battle of Fort Pillow. While the New Era was anchored in the Mississippi River, Marshall and his crew kept in touch with the fort via semaphore. Marshall ordered the shelling of Confederate positions around the fort. While the shelling wasn't accurate, it did help to keep the Confederates out of the fort during the morning of April 12, 1864.
However, when the Confederates began sniping at the ship, Marshall ordered the New Era to retreat up-river, leaving the Union garrison inside the fort to fall. Marshall was disdained by both sides after the fort fell.