Do you have any links or sources? I have never heard that and would love to read up on it.
Read Union and Confederate Submarine warfare in the Civil War By Mark Ragan 1999. he lists the CSS Captain Pierce as the sub that sank the USS Tecumseh at the Battle of Mobile Bay Aug. 5, 1864. Up to five subs were built at Shreveport, LA one of them was sent by rail to Houston, Tx.