Submarine Thresher Accident Was the USS Thresher similar to the Vasa incident?
That would be the tale of the Swedish ship Vasa.
And it’s an amazing story of people not speaking truth to power. The Vasa is kind of a skinny ship vs the USS Constitution, which only has one cannon deck, but Constitution is still a much fatter ship.
Down in the belly of the ship there is much more weight for ballast as opposed to the Vasa.
And it was a really cool story because they knew there was a problem, but everyone was afraid to tell the King.
Is that similar to the USS Thresher incident?
But I think there were fewer indicators in the case of the Thresher.
The Thresher was more of a surprise.
I don’t put Thresher in the same category as say the Boeing 737 max incidents. Now we have sees Boeing texts from some of the test pilots saying the software is going crazy. And the general consensus was that they really just tried to have engineers and programmers patch up a hardware engineering issue. Furthermore, those engines had a poor design. And so they tried to counter that hardware issue with their software program and then they didn’t even want to give the software program for free.
Boeing wanted to charge like $2 million for it, and then they gave a good enough tutorial on it. I mean, the list of critical errors goes on and on.
A little known fact is that the person who found the Titanic actually used funding from the Navy, to find the fresher, the deal was if he found the Thresher then you can go and find the Titanic.
Did we learn from the Thresher?
The Navy learned a lot.
So what happens is in a submarine there’s a lot of seawater inside the submarine, running through the pipes.
We bring water into the submarine and send it back out.
We use that to cool all the machinery.
So there are all these penetrations and when one of those internal pipes break.
Well, so the first thing is you want are valves that have fast-closing ability on these penetrations. And the Navy had a robust design process for the mechanisms.
Then when you want an emergency blow, which is what the ship did, you’re taking high pressure air, passing it through a pike, setting it into the ballast tanks. It was rapid decompression.
What happened was the air, as it was doing that froze up. The moisture in the air froze into ice.
And so it couldn’t pass through the pipe anymore.
So out of that came a whole bunch of rules, we do hourly checks on these, on the air bags to make sure the moisture is very, very, very low. We redesigned these pipes so that they’re fatter as well. The piping runs are shorter.
And then there was a bunch of work around controlling the materials used in the submarine.
So there’s a lot of stuff you take for granted. When you get sick, you get drugs from Walgreens. You assume if it says amoxicillin, you assume it’s amoxicillin.
In the Navy we test everything to make sure.
So we learned a lot. We only had one accident after that, which was the scorpion. That was a different kind of accident.
The Challenger & the Thresher incidents seem connected?
Yeah. I mean the Challenger, what a sad thing where you see the engineers, the transcripts of the engineers, basically saying this is a problem. And the guys, management, not wanting to hear it.
In fact, there was one at one point in the mint, one of the managers says, take your engineering hat off and put your management hat on. And, Oh my God. When do you want me to launch? Reagan thought it looked good for his state of the union address and they were going to launch 12 shuttle launches every month.
So it’s what we call obey the clock. Which is when the pressure of getting the thing out, overrides the integrity of the engineering and the organization.
Timeline of the Thresher disaster:
07:47 Thresher begins its descent to the test depth of 1,000 ft.
07:52 Thresher levels off at 400 ft, contacts the surface, and the crew inspects the ship for leaks. None are found.
08:09 Commander Harvey reports reaching half the test depth.
08:25 Thresher reaches 1,000 ft.
09:02 Thresher is cruising at just a few knots (subs normally moved slowly and cautiously at great depths, lest a sudden jam of the diving planes send the ship below test depth in a matter of seconds.) The boat is descending in slow circles, and announces to Skylark she is turning to “Corpen [course] 090.” At this point, transmission quality from Thresher begins to noticeably degrade, possibly as a result of thermoclines.
09:09 It is believed a brazed pipe-joint ruptures in the engine room. The crew would have attempted to stop the leak; at the same time, the engine room would be filling with a cloud of mist. Under the circumstances, Commander Harvey’s likely decision would have been to order full speed, full rise on the fairwater planes, and blowing main ballast in order to surface.
The pressurized air rapidly expanding in the pipes cools down, condensing moisture and depositing it on strainers installed in the system to protect the moving parts of the valves; in only a few seconds the moisture freezes, clogging the strainers and blocking the air flow, halting the effort to blow ballast. Water leaking from the broken pipe most likely causes short circuits leading to an automatic shutdown of the ship’s reactor, causing a loss of propulsion. The logical action at this point would have been for Harvey to order propulsion shifted to a battery-powered backup system. As soon as the flooding was contained, the engine room crew would have begun to restart the reactor, an operation that would be expected to take at least 7 minutes.
09:12 Skylark pages Thresher on the underwater telephone: “Gertrude check, K [over].” With no immediate response (although Skylark is still unaware of the conditions aboard Thresher), the signal “K” is repeated twice.
09:13 Harvey reports status via underwater telephone. The transmission is garbled, though some words are recognizable: “[We are] experiencing minor difficulty, have positive up-angle, attempting to blow.” The submarine, growing heavier from water flooding the engine room, continues its descent, probably tail-first. Another attempt to empty the ballast tanks is performed, again failing due to the formation of ice. Officers on Skylark could hear the hiss of compressed air over the loudspeaker at this point.
09:14 Skylark acknowledges with a brisk, “Roger, out,” awaiting further updates from the SSN. A follow-up message, “No contacts in area,” is sent to reassure Thresher she can surface quickly, without fear of collision, if required.
09:15 Skylark queries Thresher about her intentions: “My course 270 degrees. Interrogative range and bearing from you.” There is no response, and Skylark’s captain, Lieutenant Commander Hecker, sends his own gertrude message to the submarine, “Are you in control?”
09:16 Skylark picks up a garbled transmission from Thresher, transcribed in the ship’s log as “900 N.” [The meaning of this message is unclear, and was not discussed at the enquiry; it may have indicated the submarine’s depth and course, or it may have referred to a Navy “event number” (1000 indicating loss of submarine), with the “N” signifying a negative response to the query from Skylark, “Are you in control?”]
09:17 A second transmission is received, with the partially recognizable phrase “exceeding test depth….” The leak from the broken pipe grows with increased pressure.
09:20 Skylark continues to page Thresher, repeatedly calling for a radio check, a smoke bomb, or some other indication of the boat’s condition.
11:04 Skylark attempts to transmit a message to COMSUBLANT (Commander, Submarines, Atlantic Fleet): “Unable to communicate with Thresher since 0917R. Have been calling by UQC voice and CW, QHB, CW every minute. Explosive signals every 10 minutes with no success. Last transmission received was garbled. Indicated Thresher was approaching test depth…. Conducting expanding search.” Radio problems meant that COMSUBLANT did not receive and respond to this message until 12:45. Hecker initiated “Event SUBMISS [loss of a submarine]” procedures at 11:21, and continued to repeatedly hail Thresher until after 17:00.
On 11 April, at a news conference at 10:30, the Navy officially declared the ship as lost.