I'll provide a quick answer based on the info in Dickey and George's 1993 Field Artillery Projectiles book page 197:
- Identification of this projectile is primarily based on a report from Commander John M. Brooke, Office of Ordnance and Hydrography, Richmond, Virginia to S.R. Malloy, Secretary of the Navy, C.S.A. dated January 1863. Brooke included a detailed line drawing and stated the shell is known as "Tennessee Sabot".
General E.P. Alexander, late Chief of Artillery of Longstreet's Corps, states in Southern Historical Society papers that the projectile was called "Mullane" or "Tennessee Shell", and that Mr. Mullane had been denied a patent on it because it had already been patented by Mr. Read on October 28, 1856.
It appears applying the Read 1856 patent to the Mullane Sabot is a bit of a stretch. Much more info in the book but this generally answers it. I'm sure Pete and others can provide more detail.
Jack Bell's 2003 Heavy artillery book uncovers some newer information which indicates we should call the sabot the Gibbon sabotted shell. On page 398 of his book Jack provides a letter he uncovered in 2001 which ends with the statement:
- "By copper cup I mean the copper disc designed by Capt. Gibbon or what is called the Tennessee Shell"
So it seems to me if all of this is accurate and there is no missing data that the shell was called at the time the "Tennessee Sabot" by Lardner Gibbon.
The odd part that is still not clear to me anyway is why "Tennessee" gets into the name? Gibbon was an ordnance inspecting officer at Tredegar in Virginia.