Thank you for your response. Yes! I have visited the Cairo at Vicksburg. At that time; I checked the records there at the site. I was unable to locate my great grandfather as having been there. It seems though that his unit indeed was in the peripherial area so the tale might be so. Maybe he just related about the ship being sunk and the small grandson took it literally. I have enjoyed this site so much; I am still exploring it. Have even found some more information on Texas Partisan Rangers.