Fort Knox was completed in 1869, but its builders concentrated on Batteries A and B first, in 1844, so as to get some guns covering the Penobscot River as soon as possible.
Batteries A and B were each blessed with their own hot shot furnace. Both furnaces were built in 1858, but the guns that would have fired heated shot, 32-pounder smoothbores, were never installed. Both batteries had to be extensively reconfigured to mount big 10- and 15-inch Rodman Guns, which finally started to be installed in 1869...and Rodman Guns had no need of heated shot.
Fort Knox and its merry batteries. Click on the image above for a lovely full-sized satellite shot, minus all the pesky writing.
From the informational signs at both of the hot shot furnaces at Fort Knox:
The Rodman cannons finally installed in Batteries A and B fired much bigger cannonballs. The size, rather than the temperature of these cannonballs, could inflict damage on the fireproof "ironclads" that had largely replaced wooden-hulled ships by the 1860's.
Even though these hot shot furnaces were never "fired up," they stand as an important feature of early cannon technology.
Interestingly, Battery B's hot shot furnace is at least twice the size of Battery A's. This despite the fact that Battery B was designed to mount fifteen guns, while Battery A was designed to mount 34. Battery A faces the section of the Penobscot from whence one would expect attacking Confederates and/or the Royal Navy to emanate, which explains why more guns would be facing that direction.
Logically, this can only be explained by one of two possibilities: Either any attacking ships that took the indirect route to Fort Knox, around Verona Island toward Battery B, were thought to be somehow more vulnerable to heated shot than those that steamed straight up the Penobscot into the jaws of Battery A...or, they just built the wrong hot shot furnaces at the wrong batteries.
But of course this odd discrepancy doesn't matter, because neither of Fort Knox's hot shot furnaces were ever used for their intended purpose. Careful scrutiny of both furnace's fireboxes reveals that there probably were not fires ever built in them. Likely because there were never any cannon mounted nearby that could have utilized heated shot.
Please click on any of the images on this page to view its full-sized version.
Ever wanted to climb into a hot shot furnace? here's your (virtual) chance!
