I served and qualified aboard USS Chopper as a Machinist's Mate from 1961 to 1963.  She was a fine boat.

"Quite some time after I left Chopper I was assigned to the USS Spadefish (SSN-668).  Later I became COB and in 1977 I left Spadefish.  But before I left her, there was one morning in 1976 when a couple of Navy tugs maneuvered the ex USS Chopper alongside the pier just forward of us. She was being outfitted with buoys, cables, and other equipment to allow a ship to submerge and surface her with no one onboard.

After several weeks of installing this equipment, Spadefish was informed that we would be part of a weapons test using Chopper as our target.    Chopper would be submerged to about 100 feet on the cables and we would  test a torpedo on an actual submerged boat.   We went to sea one day and assisted in testing out the installed diving and surfacing equipment Spadefish, ran practice runs while Chopper was submerged testing her gear.

During the next several days while they were making sure that the equipment was functioning correctly and we loaded our "war shot" I did every thing I could to go through Chopper just once more.   Finally on the last night, a guy I knew let me "sneak" aboard and armed with a flashlight, I toured every nook and cranny of her.
It’s a hard thing to see the boat that you qualified on in such bad shape, but she sure looked good to me. I managed to remove a couple of nameplates  from the engine room and most importantly, a piece of her deck planking.

Next day, on July 21, 1976 we were underway and headed for the op area to do the dastardly deed. Spadefish submerged and went to Battle Stations - Torpedo.  As Chief of the Boat, my battle station was the Diving Officer in charge of the planesmen. During our final approach and while Chopper was hanging on the cables, we could hear noises coming from her.   While we were still on the approach, Chopper commenced flooding, broke her  cables, and drifted silently to the bottom of the Atlantic in 2,400 fathoms  of water.

I was relieved that we didn’t have to submit her to a violent death,  but rather let her retire gracefully where she was meant to be."

 There is a port of no return, where ships may ride at anchor for a little space
And then, some starless night, the cable slips, leaving an eddy at the mooring space...

Gulls veer no longer, Sailor rest your oar. No tangled wreckage will be washed ashore.
"Lost Harbor", by Leslie N. Jennings

Thank You "Sweetpea"