Naval Engagement at St. Johns Bluff - Part I

Harper's Weekly drawing of the Confederate Battery at St. Johns Bluff (Source: Florida Dept. of State Archives)

In prior posts, I highlighted the US Navy’s establishment of the blockade off the St. Johns River, Florida and creation of their base of operations at Mayport Mills in spring 1862. In an effort to prevent the Navy’s use of the river, during the late summer of 1862 the Confederates constructed a substantial earthworks and battery of guns on St. Johns Bluff, 3 miles upstream of Mayport Mills on the south bank of the river. This appears to have been done at the command of Gen. Robert E. Lee, whose orders to Brig. Gen. Joseph Finegan were to secure the Apalachicola and St. Johns Rivers from use by the Union forces. Work on the battery was completed in early September 1862, and it was placed under the command of Capt. Joseph A Dunham of the Milton Light Artillery Battalion. A smaller, secondary battery was also constructed upstream at Yellow Bluff, on the opposite bank of the river.

An escaped slave brought the existence of these batteries to the attention of USN forces at Mayport Mills. Although skeptical of this information, Acting Master L. G. Crane, commanding the gunboat USS Uncas, decided to conduct a reconnaissance of the Bluff. Proceeding upriver on 10 September, accompanied by the gunboat USS Patroon (Acting Master W. D. Urann commanding, who received the initial report from the escapee), Crane arrived off the Bluff that evening. He anchored, set out a kedge anchor to enable him to bring his broadside to bear, and fired nine rounds into the Bluff, receiving no return fire from the battery. Because of his initial skepticism, this may have led him to believe that perhaps things were not as the contraband portrayed.

The night passed uneventfully, but things changed radically the morning of 11 September 1862. At dawn, the Confederate battery opened fire on Uncas, which had her guns run in so the sailors could swab the decks. An utterly surprised Crane ordered the main anchor slipped and cut loose the kedge anchor. Uncas was hit five times by rounds from the battery, before she could begin maneuvering; one shot even penetrated the magazine of the gunboat. Crane finally got his guns loaded and run out and signaled for Patroon to come upriver and lend support. It took the latter ship an hour and a half to get there due to the strong tidal currents in this part of the river. Uncas and Patroon dueled with the battery for about four hours, and even managed to drive the battery’s crew off for a period of time. After expending much of their ammo, the two Navy ships retired back to their base at Mayport Mills.

Views of the St. Johns River from St. Johns Bluff, looking downstream. Confederate earthworks and battery were located roughly in this area. Note how a battery in this location would have near-total command of the river from this vantage point: