Test Depth Dive
by David Barth
September 9, 1998
During sea trials of the Lafayette, SSB(N) 616, one of our operational requirements was to dive to test depth where the outside pressure of the water would be
somewhat less than that which would crush the hull of the boat.
I was manning the communications in the Nav Center as we descended in steps. At one point, a zerk fitting for a lubrication tube supplying grease to one of the
main ballast tank valves, began to spray sea water over the Burroughs celestial tracking computer. It was common knowledge among Nav Center ETs who worked
with the civilian Burroughs reps that the Navy didn't like the Burroughs computer and preferred the unit built by Sperry. In any event, we found that the pet cock in
the line had been left open. Shutting it solved the problem.
Captain Hannifin continued to have the boat descend. Suddenly, there was a loud explosion-like sound followed by silence. Dead silence. You could have heard
a pin drop. The captain came on the 1MC and said in a calm, cool manner, "Report all leaks." There were no reports. We could begin breathing again.
After we had finished our sea trial routine that included "angles and dangles", various up and down angles of the boat, we headed back to EB [Electric Boat Division
of General Dynamics, Groton, Connecticut], on the Thames River.
A thick fog engulfed us as we slowly proceeded up the river, Captain Hannifin commanding from the sail. I was a third class ET(R) [radar] at the time, and I was
monitoring the radar set with a second class ET(R), who thought he was God's gift and lorded it over the junior sailors. I was cowed by him, and when I noticed
that it looked as though we were actually left of center channel, I didn't say anything. After all, he was senior, and the navigator, standing next to him, was asking
him for information.
Suddenly, the boat vibrated and ground to a halt. We had run aground! The look on the navigator's [LtCdr Hughes] face was shock and surprise. He was
speechless. Then came the calm, cool voice of Captain Hannifin over the 1MC: "Back full." We backed off the rocks and got back to EB where we went into
scheduled dry dock.
Going into dry dock was fortunate for two reasons. First, running aground had sheared off the pit log swords, six-foot blades that were cranked down below the
sub to measure speed through the water. Second, we needed to check for damage caused by the "explosion". What we found was a quarter-inch thick steel
plate covering a void that was crushed like a piece of thin plastic. Because it didn't have flooding slots cut into it, the pressure of deep depth had caused it to be
crushed.
I always suspected that Admiral Rickover, in confidence with Captain Hannifin, had planned for the "explosion" at depth. This would have been desirable for two
reasons, First, it would be proof that the boat had reached a specified depth, and, second, it would test the mettle of the crew. Anyone who was skittish might
go nuts at the sound of the explosion. [As a side note, after the second class ET; mentioned above; got married, he became frightened of noises like a hydraulic
valve operating, and began to cry. He was relieved of duties and got an early out.]
I often wondered if all the other boats experienced the crushed plate during the deep dive prior to the scheduled dry dock.