Large Flying Disc

I’m 84 years old now, so I had better document our sighting of the summer morning of 1951 while I’m still alive.
Location-  The Tennessee River, Tishamingo County, near Short, Mississippi, just north of the abandoned nuke reactor project, and Goat Island, on what was than called Crappie Hollow. On Google Earth you will see a pond at the north end of the nuke site. That was then a stream with a waterfall.
 Me and my two brothers had borrowed grandfathers small boat to go to the waterfall to catch turtles. Just before we returned, we were standing on the cliff to the south of the waterfall looking southwest. There were large cumulus clouds in that view, the sun to our back.
My youngest brother Said “Look at the big white bird”. We all focused on the bright object that appeared to be moving slowly, as if flying toward us. It soon became obvious that it wasn’t a bird, but a cigar-shaped object that was stationary and slowly rocking in position. A few seconds later, the object moved with instant acceleration upward, through a huge cloud, popping out of the top, again stationary, renewing the rocking motion. It was only then that we grasped the size of the object. It was very large. A few seconds after that, with instant acceleration, it went up and to the south in a curving flight and disappeared. It was only then that we realized that we had been looking at the edge of a fat disc.
Many years later, I ask if the three of us could write on a piece of paper what we saw that day. We did so, and the stories were very close to the same narrative.
So, I know they are out there. It was clear daylight, no flashing lights at night, no little green men, just a flying machine that defies what we know of physics.
It seems to me that the only way that craft could behave that way is if it had near zero mass. I have not seen anything like it since.