U.S. Submarines: Run Silent, Run Deep...On Diesel Engines?

National Interest ^ | September 18, 2014 | James Holmes

[MasterGunner01]

Here's a true story that ought to stand the hair on your head straight out. The deep dive of the USS Chopper (SS-342) on 11 February 1969. When you read this, remember everything happened in the span of 5 minutes — from peacefully cruising at 150 feet, to out of control and heading to crush depth, to emergency blow and on the surface. This is the story as pieced together by the Navy Board of Inquiry on 7 October 1969. Here: http://diodon349.com/Stories/Stories_SS/The_Deep_Dive_of_the_USS_CHOPPER_SS_342.htm.

[Redcitizen]

“30 to 60 Seconds After Loss of AC Power”...

EGAD! That sub was vertical and it seemed to me to be just about to be lost forever. What a story. wow.

[MasterGunner01]

Scary doesn’t begin to describe this. The bow went to 1,000+ feet and stern was at 720 feet with the boat nosed down at over 75+ degrees. After emergency blow, the boat flipped around and she exited the water at 84 degrees about 2/3 out of the water, slid down several hundred feet and resurfaced at 40+ degrees (dead in the water). All this in less than five minutes of absolute terror. Chopper’s crew was unscathed, but the boat was so badly damaged by her excursion that the submarine had to be scrapped. All other fleet boats in-service at the time were repaired so that loss of AC power like Chopper experienced and the subsequent malfunction would never happen again.