On April 10, 1963, the USS Thresher (SSN 593) sank during deep-diving tests about 220 miles (350 km) east of Boston, Massachusetts, killing all 129 crew and shipyard personnel aboard. Her loss was a watershed for the U.S. Navy, leading to the implementation of a rigorous submarine safety program known as SUBSAFE. The first nuclear submarine lost at sea, Thresher was also the first of only two submarines that killed more than 100 people aboard; the other was the Russian Kursk, which sank with 118 aboard in 2000.
Station HYPO 
10 April 2020 at 11:30
Thanks, Mario for this brief reminder. Please do not overlook the tragic loss of USS Scorpion (SSN 589) with all 99 crewmen. Having served aboard Scorpion, I noted that two of those lost were men I knew personally from the time when I was aboard. Scorpion had been under refit to become a SUBSAFE boat but that refit was interrupted, and left incomplete, for a deployment to the Med.
LikeLike
10 April 2020 at 14:14
I remember this like it was yesterday, graduated HS in 63. Terrible loss.
LikeLike
11 April 2020 at 09:27
The THRESHER was near the end of a shipyard overhaul and was undergoing sea trials accompanied by a submarine rescue ship. When a submarine goes on sea trials it first submerges in relatively shallow water – just in case there is a problem. A detailed check is made for any leaks – particularly in any work performed during the overhaul that could affect sea worthiness. Having conducted a successful shallow dive it proceeds to deeper water for a deep dive, again checking for any leaks. If there is a substantial leak the submarine will attempt to use speed, up angle and blow ballast tanks to reach the surface. Apparently the THRESHER sprung a leak of such volume that it was unable to overcome the weight of the additional water and surface.
LikeLike
11 April 2020 at 17:07
The loss of Thresher and K-129 were losses that ‘deeply’ effect every submariner and their families
I hope to know the real truth before I meet our real maker
very sincerely
Dean Sands/QM2(SS)/QM2/1966-1970/Tang/Plunger/Gurnard
LikeLike
11 April 2020 at 21:28
I remember learning about the USD Thresher in boot camp back in the late 80’s. From what I remember we were told that it was never recovered along with the crew.
LikeLike
12 April 2020 at 18:58
My late father was a submariner. He was part of the commissioning crew on SWORDFISH (SSN-579). He took the loss of THRESHER quite personally.
THRESHER sank a year or two after my dad left the Navy. I was in high school and wrote a letter to Admiral Rickover expressing my condolences. To this day, I have great respect for “Rickover.” He certainly polarized people.
Thank you for remembering THRESHER and for the comment on SCORPION. Hopefully we’ll never lose another submarine and its crew.
Happy Easter!
LikeLike
18 April 2020 at 22:17
My father served aboard her and was on the surface ship when she went down. It destroyed him when he passed his ashes were spread over the site
LikeLike