High pressure air? What PSI is the tanks topped at? And how big are the tanks? Tell more about the air line that keeps water from freezing at the nozzle inside the ballast tank.
Thank you for bringing back the series. Sub Brief, I adopted a rescue kitten - it's a ton of work and expense, but now I don't wake up an angry veteran anymore because I wake up to a happy purring cat. Thank you for your educational content which has greatly increased my naval warfare knowledge.
Very nice to see you going back to the format that first drew me (pun intended) to your channel. This sort of detailed explanation of how subs actually work simply is not available anywhere else.
*"drew me"* What? You're Robert not *Leroy!* He didn't draw Robert. Honestly, I saw the text "first drew me" and thought maybe you were making a joke about being named Leroy. Apparently I'm not very good at speed reading.
Some questions (might be enough for a part 2, if you collect questions for a couple of days): 1. The obvious one first: If those are the "main" ballast tank there are obviously more. Do the others work on the same principle? 2. Are the main ballast tanks (or probably the others?) linked into pitch control? 3. How do you service these "have to be closed to the inside" tanks your life depends on? Is there some screwed close hatch to the inside or the top to do maintenance in port? 4. Good there are backup systems for the valves on the top. I assume there are also backup systems for the hatch on the top?, because if that stays open ... My guess (for 1 and 2) would be: Main ballast tanks only to get it perfectly balanced at your target depth with all controls zeroed and all the other ballast tanks and control surfaces to angle your boat however you want. BTW: Thanks for bringing back whi... bla.. whatever colored board. Really liked that series.
Main ballast tanks are only flooded or not flooded. They do the bulk of the work to get the submarine to submerge/surface. Then you have multiple smaller trim tanks around the sub. These trim tanks are used to finetune buoyancy, and balance the pitch/roll. Then additional ballast tanks to compensate for the loss of weight when weapons are launched. As for servicing, I have no Idea, but I would suspect they are only really serviceable in drydock.
On 688's, 637's and 594's you can access the MBT's through the grates on the bottom when you are inport. To do that your ships divers or divers from the repair facility go down and let themselves in. Then they do what ever needs being done in there. This brings up a whole discussion about subs and divers and safety and tagouts. Also I am not saying that the other boats don't have grates. I am saying I never touched a boomer or anything older than the Gato (except to take a tour on a museum ship).
To do maintenance in the MBT's, you have to enter drydock. Once the boat is out of the water, you can open the MBT grates on the keel. Then you go into the darkness of this slimmy tank and do your repairs. Been there, did that. MMC/SS AGANG RET.
A USN veteran I worked with told me about the 'trimming parties' they'd have on his attack sub when someone was getting certified as helmsman or setting trim. Basically everyone that could would walk back and forth and side to side in order to 'break in' the new guy. All in good fun and also to make them sweat a little.
god i love this series i hope it never leaves i love how it really makes me think leaves me wondering things researching stuff sometimes for hours after the video.
thank you so much for switching to a black background - I couldn't watch the old whiteboard series. I do wish your old content was back online, though.
Air compressors are a think. They pack air from inside the people tank into the HP Air Banks. Which means when we go up to periscope depth sometimes we ventilate just to put air inside the people tank.
As just a car mechanic and apprentice power engineer, If i might take a crack at whats in the tanks -- In the forward tanks, Torpedo tubes and doors, Sonar dome, whatever version of VLSS it may have; rear tanks - shaft for the screw/s or propulsor, Rear Torpedo Tubes and doors if equipped, decoy/noise generating devices and/or their own launch tubes; in both tanks - sensors of some kind to indicate ballast tank state, water temperature and/or other monitoring devices (IE Salinity, radiological, possibly biological/chemical sensors, pressure sensors possibly, of course related plumbing/mounting hardware, actuating mechanisms for the top vents, maybe outer trim tanks, also, would there be any form of baffles to limit sloshing of water? Of course, all this is 'general', as there'd be wide variations between classes, designs, and probably even individual boats. As a 'general' question, would there generally be separate main and emergency blow tanks? Also - where might the anchors be located? Always great to see your work! And yes, i know, 4 months late, sorry!
So the pipe that feeds compressed air to the ballast tank to allow the sub to surface can get iced up if this "feature" is not controlled. Was that the problem with Thresher?
Great video, learned a lot :) Never would have guessed that a sub was so near zero bouyancy it could be hard getting one to submerge.. A question for you, or anyone who feel inclined to answer: What if the submarine submerges with say 10% of the ballast still being air, when it gets deeper I'm assuming that airpocket gets smaller and smaller as it gets compresssed, letting more water in and increasing weight. Can this lead to an uncontrolled dive? Or am I fundamentaly wrong?
Items in the ballast tank. VLS missle systems, the anchor, torpedo tubes pass through, and my personal favorite (as a nuclear operator) the shaft. Propulsion above all else.
Once ballast is adjusted to submerge, it is mostly propulsion that adjust operating depth. some adjustment of ballast is necessary for trim. when really deep, is there some measurable compression of the sub? requiring ballast adjust?
Fascinating. Subscribed. Do subs have plimsoll lines to ensure the ballast is correct before leaving port? Does the water slosh about in the tanks or is it full to the brim? If it can slosh then do they have baffles to quieten them? Why do they have trim tanks if you could potentially do it all with the main ballast tanks? Is trimming done automatically? Is everything the same in a double skinned sub?
A couple of questions. With the drain grates are how do you keep the grates from making noise when the sun is underway. And you mentioned the ballasting of your boat, if the trim is that sensitive with full forward and aft tanks full, how do you account for the salinity of the water and when you are transitioning from high to low such as going into the Gulf Stream from the Caribbean Sea?
The grates are not loose, they are fastened to the ship so that they don't rattle, but are removable. Salinity changes is most common in the Arctic (ice freezing or melting). Temperature changes are more common (Gulf Stream, or depth). We have what are called Trim tanks that let us bring water in or out and move it around.
I've been trying my hand at designing a autonomous midget drone sub and have been reading a lot of Ulrich Gabler's writing on the subject...he designed the Type XXI sub during the war along with several other types, plus several post war designs...and Mr. Gabler indicates that the top vents should be placed as far back as possible when engineering the ballast tanks, or else the sub can dive at an awkward angle. He goes on to mention those slits at the bottom as a source of eddy currents between the pressure hull and outer hull, the energy creating those currents has to come from somewhere: your propulsion system. So a lot of care is usually taken in their design. Those valves connected to the "captain's flask" I think are shuttle valves...the act like normal hydraulic valves until you add pressurized air on the far side of the valve, which closes of the hydraulic input and shoots compressed air to whatever piston the hydraulic fluid was driving. Combat aircraft back in the day had a similar system in case the hydraulic lines were compromised or the engine driving the hydraulic pump was no longer running. It was a last ditch effort to lower the landing gear and flaps. Usually would result in the entire hydraulic system having to be purged a refilled later...better to have to do that than to write off an expensive plane!
Did the USS Connecticut lose it's full front ballast compartment when it hit the undersea terrain? Looked like the whole front of the ship ripped off. I assume they were scared for their lives hoping the rear main blow would get them to the surface. Now to answer your question, torpedo tubes, the main sonar array, and maybe an anchor system? (runner up, some kind of concealed/retractable thruster?)
I had a couple uncles that served on WWII subs. I've been on a couple old subs, not part of the crew. WWII grates had valves. When the valves were left open on the surface they called it riding the vents, It was for faster dives. I wonder if the design change from then to current subs had to do with the Thresher and Scorpion? With no grate valve, air pressure would have to be maintained on the surface. So what happens during fitting out and overhaul? Or mothballing?
The valves at the bottom openings of ballast tanks are called "Kingston valves" in most books I've read on submarines. WWI-era submarines in most navies had them. Friedman's 1994 book "US Submarines Through 1945" writes that Kingston valves were phased out in US submarines mid-WWII.
Very interesting, thanks for making the vid. But this leads to further questions about the compressed air and where it comes from. I assume there are multiple rotary screw compressors on board to replenish the ballast tank air tanks but where does the air come from? One cubic metre at multiple barr pressure inside the ballast air tanks would mean multiple cubic metres of uncompressed air to source the compressed air. Air would be at a premium in a sub I would assume and no one wants to work in a vacuum (literally). Big gulp at the surface?
QUESTION: does the submarine use ballast to control its depth in the water at all? In cold waters i use ballast tanks constantly, is that realistic? Wouldn’t you run out if compressed air if you did use flood and then blow ballast tank constantly.
Things in ballast, torps, diving planes, sonar. Also, maybe trim tanks? Seems like you'd want those far forward and aft to get the most adjustment potential for the least trim ballast. (total guess)
Also a safety aspect to have grills in the bottom of the ballast tanks. If you have valves there instead and they fail, you can't drain the tank to surface. Good stuff though. I'm a civilian engineer on submarines and this is all very interesting to watch.
Somewhere, I suspect Silent Service, there was a Depth Charge that exploded not too close but directly under the submarine so that the gasses rose into the grill, displaced the water, and the submarine uncontrollably rose towards the surface.
On US boats the tubes are usually run out the side of the boat. But the Sonar dome is there. I am thinking any VLS tubes for missiles. But maybe a towed array system might be external to the pressure hull.
4:05: Would your submarine lose a noticeable amount of negative buoyancy through the course a of deployment as munitions and food and other expendable items are consumed?
I can't speak for now, because now may be different. But Subs go into overhaul (in a drydock) 2 or 3 times over their lives, but also go into drydock every few years for upkeep or repair. When they do this the hull get blasted clean and the tanks also get a good going over.
It makes sense to me that you'd have a fixed opening at the bottom of the ballast tanks rather than a valve. There is no reason you'd ever want them closed. (I guess unless the whole sub is upside down, but I'd say you're already screwed if that's happened!) Being able to close off the tanks would mean they can be at a different pressure to the exterior which I'm guessing they are not designed to handle and they would either rupture or crush, depending on which direction the pressure differential goes.
Sonars, sensors, torps, hatches. Good series. I had forgot this. I will keep this in mind for my models. I wonder if subs experiment with different gas mixtures.
The bow plane are for main debth control. Stern planes mainly control the bubble or angle of the ship. At higher speeds, stern planes can control debth. Rudder is use to stear the boat and control the coarse.
When the tanks are blown at great depth (high pressure), are they blown until the water is completely driven from them, or just partially blown, and the air bubble allowed to expand as you go to shallower depth?
I was wondering about how they solved the freezing problem that doomed the USS Thresher by in the 60s. I do remember a plan of placing a kind of rocket motor that would be used in an emergency to empty the tanks. I doubt if they went thru that at least never heard about it again.
Great info! Love to learn the basics of how subs work. I have been reading novels about subs since the 80’s. So I think there are torpedo tubes in there. Perhaps some sonar / listening devises. And of course Tom Clancy’s writing room! Duh!
torpedo tubes and sonar array would have to go through / be in the ballast tank, yes? also the propulsion system / propellor shaft? with the grates in the bottom, wouldn't this mean if the sub ends up on its back somehow, you can't surface? i guess that would have to have been assessed to be just about impossible, right?
I have a non-related question. I know all submariners train hard to fight fires and "leaks", but do they have to qualify in the sub as well as part of their process to get their dolphins?
If the submarine lost all power for example - could the valves be actuated by hand? Could the submarine surface by just having people rotate certain valves? Edit - My question was answered at the end!
3:05 Would their ever be a need due to failure or damage to need to dispose of these lead weights in order to serface !? If so. How do you get rid of the lead weights under water ?
@@MarkLawrenceKiefer I figured it's bad, I just wasn't sure if there was a process to block the vents if it gets toppled over so that they can still blow main ballast somehow
The bow sonar sphere, the torpedo tubes (except the loading parts), and the VLS Tomahawk tubes (for those that have them). In some classes, a towed sonar area is stowed in the after ballast tank.
Inside the forward ballast tank...torpedo tubes, anchor locker, forward signal buoy, forward escape hatch?...err, water, bits if that, yeah? Vertical launch tubes? Nemo and Dory, if you're on a Westpac near Australia....
@@taco44051 wasn't sure if those would be part of the ballast and they aren't in all subs at the bow which is why I didn't mention them. My parents used to work where they made the sonars. But also with that, not fully sure if it's in a free flood area or would be considered ballast tank
Do you know how a submarine, especially a small research vessel maintains it's internal (passenger compartment) air pressure? Scrubbers remove CO2 but if oxygen is bled from bottles into the interior does the pressure slowly increase during a dive? Since the pressure is greater outside the hull, you cannot simply open a valve to vent the rising internal pressure. Does the CO2 scrubbed equal the O2 added during a dive? Are compressors used to pump out the excess internal air to maintain a constant pressure? Or, do you simply live with the gradually increasing air pressure?
When air volume get low, the ships atmosphere starts going into a vacumn. You have to go towards the surface and at PD, snorkel or ventilate to burp the boat. Take a gulp and go back down. You place a positive pressure in the boat so your volume increases. Yes, you can run out of air. You have oxygen banks that can keep you alive for a time. But the cannot charge the air banks.
3 things inside of a ballast tank that are not a part of the ballast system? If it's a 688i or newer then it be Torpedo tubes, Active sonar array, and VLS tubes.
