Smarter Everyday visits a submarine.

[actaeon277]

Oh for sure you don't just trust the systems. I'm shocked that there was a human failure far enough up the chain to let water in the boat from the snorkel at all. Heavy seas splash over it or was this a full-on dunce move?

As a side note, fully understanding that it's a dangerous job, given all of the ways you've outlined how to easily die (and a few times you thought it may be a risk), what was a respectively "care free" day on a sub like? I would think various quiet ops, which can't be discussed, would be areas of general low stress? Fewer drills and such maybe?

The diesel sucks in serious air. And the mast doesn't stick above the water very much.
Kinda like this..

So, moisture is brought in.
It comes down the trunk, into a sump.
There it makes a 180 degree turn.
The water can't make the turn, the air continues up and out the top of the sump.
There is a window there to watch.
A watchstander sits there when snorkeling, his only job to watch the window.
But, it's a boring watch, so it's usually a junior watchstander.
He called the control room to report "There's a lot of water here".
The replied back that was okay, "There's always water there".
And they were right. It always looks like it's raining.
But when the watchstander said "There's a lot of water here", he meant, there was a SOLID SLUG OF WATER.

So we filled the Operations Compartment bilge, all the way to the floorplates, and into my bunk which was the bottom of 3 bunks.
When I jumped up and called away flooding in Ops Lower Level, they realized they maybe should have listened better.


So, the interlock failed.
And the human element failed.

We were lucky.
On the surface, water pours in.
Real deep, you can be dead before you knew the water was coming in.

At test depth, water breaching into the sub can completely fill it in less than a second.

 

[maxwelhse]

Fascinating stuff, Act. There's the big picture stuff that I think most people understand, but I had never considered something like a Diesel intake water window before. Frankly, I hadn't considered that even running a Diesel would be a thing in the nuke era.

 

[actaeon277]

Fascinating stuff, Act. There's the big picture stuff that I think most people understand, but I had never considered something like a Diesel intake water window before. Frankly, I hadn't considered that even running a Diesel would be a thing in the nuke era.

If you SCRAM the reactor, the only thing providing power is the Ship's Battery.
There is only so much power there. And every second, amp-hours are clicking out of it.
You need to cut all non-essential load QUICKLY to maintain battery power.
You need to maintain enough battery power to run the equipment necessary to restart the Reactor.

So, a diesel generator is real nice to maintain the battery.
On a sub, power is life.
So, if you SCRAM the reactor, and kill your battery...


Also, if you need to change the air on the sub.
Poisonous gas. Radioactivity in the air. Smoke from a fire. Or 30 dozen bad eggs (don't get me started on that story).
If you need to change the air, you can use the Ventilator, which takes a while, and uses power NOT generates power..
Or you can bring up the generator.
The genny can supply electric loads, and quickly cycle the air out of the sub.
In fact, the ventilation system is designed with that in mind.

The diesel actually takes a suction from inside the boat. On my sub, it took suction from AMR2 (Aux Machinery Room 2).
And it exhausted the air out the Snorkel. Actually, out the Snorkel, but under the water level, to disperse the "haze" of the diesel, and to TRY to prevent the exhaust from being sucked into the suction.
So, the suction where the diesel is (in my case, AMR2) causes air to be drawn from the forward compartments.
The forward compartments then draw air through the Snorkel suction.


So, to rephrase..
Air enters the Snorkel suction, into the torpedo room, through the Ops Compartment, to Missile Compartment and AMR1, to AMR2 and the Engine Room, into the Diesel, and out the Snorkel exhaust.
Thus, changing the air on the sub.

 

[actaeon277]

We had a Fairbanks Morse, very similar to the WWII models.
Looked a bit like this.

Except crammed into a sub hull, so not as much room as you see there.

I hear the new gennys are better and smaller.

 

[maxwelhse]

It all makes sense when you say it, I had just never thought about it before.

That is also a WAY bigger Diesel than I was envisioning for that role. Holy crap!
!

 

[actaeon277]

The Diesel is air start. So if you kill the battery, you can still start the generator. Providing you haven't killed the air banks.

 

[actaeon277]

Here is a WWII boat, the Silversides.

You might skip through the video a bit, it's a bit boring.
But it shows them starting one up, in the sub.


[video=youtube;6Cf0gxvYqBY]https://www.youtube.com/watch?v=6Cf0gxvYqBY[/video]





Remember.
You have to make sure the "start air" is lined up.
Fuel on.
Snorkel dampers are open.
Cooling water open.

And more stuff i didn't have to deal with.
I didn't run the Diesel.
But the AMR2 Upper Level (me, when I wasn't Reactor Operator) had to line some of the stuff up, and open the Snorkel dampers.

 

[actaeon277]

It might have affected my hearing.

Also, while Diesel Boats are absolutely the quietest thing out there, while on Battery, they will have to start the Diesel sooner or later.
And then...

 

[actaeon277]

You also can use the Diesel if you are exiting port and you see a Russian "trawler".
The trawler was not a fisherman. Well, maybe they did some.
But they were really AGI (Accoustic Gather Intel) (I think).
They stayed outside naval bases, but in international water where you couldn't do anything about it.
They would try to have spies find out if a sub, or ship, was leaving port, then the AGI could collect sound data points on the vessel.
Even if they didn't have a spy to find out the name, they could visually see if you were a ship or sub, and infer the class from visual.
Then they would record the acoustics.
This would be used later, if they were tracking a target, and their person or computer could compare the sounds and then they could identify it.


But, if you ran the Diesel, they couldn't hear the Nuke stuff. So you would mask your noise exiting.

 

[indyartisan]

Love the posts and pics.
We took a trip through a WW2 sub up in Michigan.
Amazing how little room there was for the crew.
They had taken the all the guns off it.
The guide told us it was because of a treaty with Canada.

 

[actaeon277]

Sometimes, the Snorkel goes to high, and the exhaust gets sucked right back to the suction.
Guess what happens then.

Well, the sandwich you're eating starts to taste a bit funny.
And the room gets a bit hazy, gray/blue.


It is not pleasant.

 

[actaeon277]

This is a bit older, and for the diesel boats, but the basics are the same for the sub.


[video=youtube;rCBJ_0vX3AQ]https://www.youtube.com/watch?v=rCBJ_0vX3AQ[/video]

 

[maxwelhse]

Sometimes, the Snorkel goes to high, and the exhaust gets sucked right back to the suction.
Guess what happens then.

Well, the sandwich you're eating starts to taste a bit funny.
And the room gets a bit hazy, gray/blue.


It is not pleasant.

I've been a hobbyist mechanic for over 25 years now... that's just added flavor.

And I can only imagine how loud an air starter on that engine would be inside a steel tube. Air starters on road going vehicles are loud as all hell and they're starting about 1/20th the amount of engine.

I've been through the U boat up in Chicago so I have a reasonable understanding of the general sizes of that era of sub. I still would have never guessed the backup on a nuke sub would just be the straight up power plant on a WW2 version. Crazy stuff.

 

[actaeon277]

The Fairbanks Morse was a tried and true work horse.
If it works, well, we love it.
Too many things with all the new bells and whistles, fall on their face.

You could flood the FB. Drain it out. Blow air through it. And light it up.
Obviously later you'd want to perform preventative maintenance on it.
But in a pinch, it would save your ass.


I can't remember the name, let me see if I could look it up..

Nope, couldn't find it.
I think the name started with H.
Hoover, or something like that.
Anyway, the diesel was so bad, that subs installed with that diesel eventually had to have the engines pulled and replaced.
Just a note, there are no hatches for pulling out diesels.
You have to cut a hole in the hull.

 

[actaeon277]

https://en.wikipedia.org/wiki/Fairbanks_Morse_38_8-1/8_diesel_engine
[h=1]Fairbanks Morse 38 8-1/8 diesel engine[/h]
The Fairbanks-Morse 38 8-1/8 is a diesel engine of the two-stroke, opposed-piston type.[SUP][1][/SUP] It was developed in the 1930s, and is similar in arrangement to a contemporary series of German Junkers aircraft diesels.[SUP][2][/SUP] The engine was used extensively in US diesel electric submarines of the 1940s and 1950s, as backup power on most US nuclear submarines, as well as in other marine applications, stationary power generation, and briefly, locomotives. A slightly modified version, the 38ND 8-1/8, continues in service on Los Angeles-, Seawolf-, and Ohio-class nuclear submarines of the US Navy. The 38 8-1/8 has been in continuous production since its development in 1938, and is currently manufactured by a descendant of Fairbanks-Morse, FME, in Beloit, Wisconsin.

 

[maxwelhse]

https://en.wikipedia.org/wiki/Fairbanks_Morse_38_8-1/8_diesel_engine
Fairbanks Morse 38 8-1/8 diesel engine


The Fairbanks-Morse 38 8-1/8 is a diesel engine of the two-stroke, opposed-piston type.[SUP][1][/SUP] It was developed in the 1930s, and is similar in arrangement to a contemporary series of German Junkers aircraft diesels.[SUP][2][/SUP] The engine was used extensively in US diesel electric submarines of the 1940s and 1950s, as backup power on most US nuclear submarines, as well as in other marine applications, stationary power generation, and briefly, locomotives. A slightly modified version, the 38ND 8-1/8, continues in service on Los Angeles-, Seawolf-, and Ohio-class nuclear submarines of the US Navy. The 38 8-1/8 has been in continuous production since its development in 1938, and is currently manufactured by a descendant of Fairbanks-Morse, FME, in Beloit, Wisconsin.

That engine appears to still be in production today, can run on either diesel OR gas, the "big" version has a displacement of 12L per cylinder... x12 cylinders. 144L of 2 cycle goodness.

From a brief skimming, basically if God designed an engine that would almost never go down, it would be that thing.

 

[actaeon277]

Well, when you're out cruising IN the ocean, that's what you want to hear.

 

[actaeon277]

https://www.youtube.com/c/JiveTurkeyCrew/videos

This guy has some good explanations.
But you have to go back a year or so.

 

[maxwelhse]

Nukes, shipwrecks, thieves... I couldn't not share it here.

[video=youtube;Rme9cGXyY8M]https://www.youtube.com/watch?v=Rme9cGXyY8M[/video]

 

[Dave A]

On 594 class boat near the top of the snorkel mast were sensors to detect if water was about to cover the headvalve at the top(opening) of the snorkel mast. Water gets too high a high pressure air line would close the headvalve, water goes down the air is released. It sounds just like the air brake relief on a tractor trailer truck. At the bottom of the snorkel mast is a blower to pull air through the mast and into the boat. While this is going on either the diesel generator is running or the low pressure blower is running. Air in must equal air out or your ears hurt. We rarely ran the diesel, the reasons we did in order, 1) training 2) preventative maintenance 3) some kind of power plant problem. The diesel generator was a Fairbanks-Morse in the lower level of the bow compartment and it generated 450kw of DC. I don't remember the voltage.
Most of the time, either daily or every couple days depending where we were or the condition of the boat's atmosphere we would snorkel to ventilate the boat. This means running the pressure blower while snorkeling and discharging the blower air out the rear of the sail. The low pressure blower can also discharge into the main ballast tanks to surface the boat.

The trash disposal unit does have interlocks to prevent the outer door being open at the same time the upper door is open. A qualified chief always supervised the operation of the TDU. The only problem we ever had with the TDU was the lower door did not seal completely during one cycle, so when the upper door was opened water came out like an overflowing toilet. Messy but it had enough pressure that they could not force the upper door closed. The boat was surfaced which reduced the pressure enough to close the upper door.