Preventing tractor back flip

[bcp]

The way I heard it, the skipper knew his surface was being filmed, so he thought he'd give 'em a show. Nearly lost the boat going back down past test depth, stern first. Did lose his commission, so the story goes.

Navy caption says it was an emergency surface test.

Another one:

 

[Short Game]

Navy caption says it was an emergency surface test.

Yeah, I read that too. So, either what we heard there in the squadron was pure skuttlebutt, or there was a coverup in the military (unthinkable, right?).

PICKEREL supposedly went stern-first below test depth after that stunt.

From: The Stupid Shall Be Punished: 48 Up!

===================

The story is out there. We all knew that picture from the film of it, which was seen every week in the opening scene of the '50s TV show, The Silent Service. The Pickerels wore that pic like a badge of honor (claim to fame, at any rate).

I was on the same class of boat. Stuff happens. This is a pic from before I was there, so I didn't do it.

Another view of that is here:
http://www.navsource.org/archives/08/08490.htm

 

[bcp]

Video of the surfacing at 1:14 to 1:35. At 1:17 is when the still photo matches the video.

It didn't do a back flip because the load was properly hooked to a well-designed drawbar.

USS Pickerel SS524 Surfacing Video by Douglas J Waters - Myspace Video

 

[SPYDERLK]

However, these guys did lose the bubble:

USS Pickerel (SS-524) surfacing at a 48 degree up angle, from a depth of 150 feet, during tests off the coast of Oahu, Hawaii, 1 March 1952.

The way I heard it, the skipper knew his surface was being filmed, so he thought he'd give 'em a show. Nearly lost the boat going back down past test depth, stern first. Did lose his commission, so the story goes.

It sounds like control of the vessel was lost as a result. ... Looking at the video the sub appeared under perfect control at moderate speed for at least 10 seconds after the pop when filming ended. Did things go crazy after that? :confused2: Can you explain the mechanism?
larry

 

[Short Game]

It sounds like control of the vessel was lost as a result. ... Looking at the video the sub appeared under perfect control at moderate speed for at least 10 seconds after the pop when filming ended. Did things go crazy after that? :confused2: Can you explain the mechanism?
larry

Firstly, we have a 1570-ton Tench class submarine that is sticking a good portion of said tonnage from the heavy medium of seawater into the lighter medium of air. At the peak of the upward lunge, the boat is blowing ballasts and maximum powering up from 150 feet, exceeding the surface by maybe 60 feet, and maybe as much as 300 tons less seawater is being displaced. No longer displacing all that seawater, at that moment, that boat would be as much as that, negatively buoyant. The boat is about 300 feet long, its test depth is something like 407 feet. When the boat starts back down backwards, pushed by all that weight, how deep will the After Torpedo Room be? Those old boats had many systems connected to seawater through hull valves. These valves normally remain open at 150 feet. Beyond 200 feet depth on this class of boat, a condition known as, "Deep Submergence," is set, requiring the shutting of all the hull valves on systems not designed for the heightened pressures.

Now, I for one was on a boat just like the Pickerel, and I and my 80 companions also experienced losing the bubble, but in our case, it was a fast dive drill, during which an AC power system failed, resulting in loss of hydraulic power to the bow and stern planes, among other things. We took a 37 degree down angle with "all ahead, flank speed" the last order to the Maneuvering Room. Our bow exceeded test depth before we came back into level running, amidst plumbing failures throughout the boat, as we never had the time to "rig for Deep." Coming back up, we well exceeded 30 degrees up angle, as the forward main ballasts had been blown on the way down.

All the mess of various benches, loose gear, and exploded Pyrex coffee cups, piled up at the front ends of the various compartments then went crashing aft. In the Control Room at the time, the main hydraulic supply tank was in the process of being topped off and several 5 gallon cans of hydraulic oil were sitting open and ready to pour. These overturned and added a nice touch to the mess. We never tried a drill anything like that again. And I believe there is nothing much in the ship's log to say it ever happened, though the crew was busy for two full days, cleaning up the mess.

I wasn't on the Pickerel that day, and I'm glad of that. I would have been scared sh*tless. In our case, we had a good young skipper who had recently taken command and his boat was fresh out of a shipyard refit. He wanted to put it through its paces. He learned something that day, and I believe that after that sobering experience, he rigged in his planes just a bit. I was only in about my third week of submarine duty without even the benefit of Sub School. I was mostly ignorant of the danger I had been in. After another two years of serious emergencies, I had been converted. I don't think those old diesel boats were a safe place to be. I became one of those who thinks, when your number's up, your number's up. I rode motorcycles for years after I got out, and I still believe that. Too many close calls in my lifetime. A tractor up on two wheels seems pretty mild in my old age. Still gets the blood flowing, though.

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On edit: Looking again at the pictures of Pickerel, I see that there is still rise on the bow planes. I can only assume there is still rise on the stern planes (with power still maxed at the screws, this is pretty much the equivalent of pulling from above the rear axle). I understand at this moment, there is no longer any deck under the planesmen, and they can exert no effort to change this, even if ordered. Nobody in the crew has a place to stand at this moment, except maybe on a rear compartment bulkhead. They are not strapped into bucket seats at control consoles. I can only think that just about everyone in that crew knows that things are not quite right at that moment, but can see little they can do about it. The full rise on the bow and stern planes will slowly help them level off as they are backing down into Davey Jones' Locker and the deep six. They were a lucky bunch of guys that day.

 

[SPYDERLK]

Firstly, we have a 1570-ton Tench class submarine that is sticking a good portion of said tonnage from the heavy medium of seawater into the lighter medium of air. At the peak of the upward lunge, the boat is blowing ballasts and maximum powering up from 150 feet, exceeding the surface by maybe 60 feet, and maybe as much as 300 tons less seawater is being displaced. No longer displacing all that seawater, at that moment, that boat would be as much as that, negatively buoyant. The boat is about 300 feet long, its test depth is something like 407 feet. When the boat starts back down backwards, pushed by all that weight, how deep will the After Torpedo Room be?

Interesting set of variables. Lots of things could happen. Did you look at the film clip posted in #333? Sure looked like it had stabilized on the surface.

 

[crash325]

Back in the late 50's early 60's I was crew member on P5M sea planes. Was not on the flight and don't have any pictures.

A bunch of big shots, congress men & such came out to observe operations. One of the boats went all the way down to the foot of Broadway in San Diego CA. 4 Jato bottles attached. Full power on the 3350's, at North island they had more than enough speed to be flying. Just as they got to the big shots, all 4 jato bottles were fired. Instant 2400 horse power.

They pulled the stick back and went almost straight up, to about 500'. Small problem, jato only lasts for about 30 seconds and they had not nosed over when the jato quit. Sure looked like they were going into the drink. With less than 100' they did recover and stated to fly.

Not sure about the big shots, but I was not impressed.:laughing:

 

[jim7631]

All,

I just joined TBN and part of the registration is posting for the first time. This string looked particularly interesting, anyway - what is the moral of the story? What should I know to not kill myself trying to move an object too heavy for my JD 1050? In a previous life, I had bad experiences drawing vectors for a demanding (and obnoxious) instructor - when someone recommends getting out the paper & pencil, I generally look for the door. Is it correct to say that pulling from the front while in reverse is safest?

Jim

 

[Short Game]

Shall we take it from the top?

 

[TripleR]

All,

I just joined TBN and part of the registration is posting for the first time. This string looked particularly interesting, anyway - what is the moral of the story? What should I know to not kill myself trying to move an object too heavy for my JD 1050? In a previous life, I had bad experiences drawing vectors for a demanding (and obnoxious) instructor - when someone recommends getting out the paper & pencil, I generally look for the door. Is it correct to say that pulling from the front while in reverse is safest?

Jim

Jim, to be honest, I have been with this thread from the beginning and I don't think there is a consensus. You might start from the beginning and go through it if you haven't already and see if you can find one, I just don't remember one myself. I personally don't like to pull heavy loads from the front, but I have.

Good luck.