# Can submarines be refuelled or resupplied under water? **URL:** \ **Category:** Factual Questions\ **Created:** [September 22, 2021, 10:10am UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109 "2021-09-22T10:10:08Z")\ **Posts on this page:** 14\ **Page:** 2
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [September 22, 2021, 5:03pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/21 "2021-09-22T17:03:02Z")
> [@Velocity](#): > > The other thing to consider is that a submarine’s endurance isn’t just limited by its food supply. There’s also the mental factor as well. You don’t want the crew to remain cooped up in an enclosed space for too long. Define too long. 😉 Because the U.S. Navy had no problem sending us on six-month long overseas deployments. I’ve spent as long as four months continuously submerged. And even between major deployments, we spent more than 80% of our time at sea. The taxpayers aren’t paying for billion-dollar vessels to stay tied up to the pier, after all. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [September 22, 2021, 5:05pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/22 "2021-09-22T17:05:17Z")
I see, didn’t know that. For some reason I recalled reading somewhere that the human mental endurance in such confined space was only about 2 months. Guess I underestimated you dolphins. 😉 ---
**Author:** ![Martin\_Hyde](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@Martin\_Hyde](https://boards.straightdope.com/u/Martin_Hyde)\ **Post date:** [September 22, 2021, 5:54pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/23 "2021-09-22T17:54:40Z")
He never said he came out of it sane. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [September 22, 2021, 5:58pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/24 "2021-09-22T17:58:49Z")
> [@Velocity](#): > > Could the reactors have a longer lifespan just by having a bigger compartment to hold fuel? (I’m sure there must be more to it than that - if it involves classified info, then no need to divulge) The fuel is packaged into the reactor core, so there is no removing and replacing individual fuel elements; at ‘refueling’ the entire core is removed and replaced during mid-life overhaul. It should be understood that the fuel elements in a nuclear reactor aren’t consumed they way a chemical fuel like oil or coal is; they produce energy in which a thermal neutron is absorbed by the enriched uranium (235U) and undergoes fission (~82% of captures) or produces 236U, while the overall volume remains essentially constant and the reactor requires higher neutron flux levels to achieve the same level of output as it ages. In order to make a reactor running at some constant power level last longer, the core either has to be made larger (impractical as the size is limited by the diameter of the pressure hull) or by using a higher level of enrichment in the fuel. There are some other nuances regarding neutron absorption by non-power generating isotopes and neutron damage to materials within the reactor that govern core and reactor lifetime but it isn’t as if the engineering staff is swapping out fuel elements or doing any kind of service within the reactor core; they are monitoring the state of the nuclear core and servicing the outer coolant loop and power generating system that converts the thermal energy into electricity and mechanical power. Stranger ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [September 22, 2021, 6:17pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/25 "2021-09-22T18:17:40Z")
> [@Velocity](#): > > For some reason I recalled reading somewhere that the human mental endurance in such confined space was only about 2 months. Guess I underestimated you dolphins. 😉 I’m sure that @robby can speak to this from the standpoint of actual experience but the psychological evaluation of the ability of ‘nucs’ to be able to work in confined situations with a relatively small crew for months on end is as much a part of selecting appropriate people as is mastery of the technical skills. You really have to be able to tolerate the sight, sounds, and especially smells of people you may not particularly like without losing your temper in addition to all of the other inconveniences and indignities of living abort a submarine, so it definitely isn’t for everyone, and of the ‘nucs’ I’ve known most have gotten pretty tired of the life after a few cruises even though they essentially have a multi-month vacation when they return (unless they are schooling for advancement or doing some other posting), and having crew members ‘crack’ under the pressure is not unheard of, although it mostly consists of underperformance or refusal to do duty rather than a _Crimson Tide_-style conflict. When people talk of sending a crew of four or six people on a multiyear mission to Mars on the basis of experience with 4-6 month submarine deterrence patrols I have to wonder how much they really understand the stress that would entail. Anyway, getting back to the question of the o.p., here is what an [at-sea resupply of a ballistic missile submarine looks like](https://www.youtube.com/watch?v=HW6nvFtc98U). As a diver, I cannot even imagine trying to do that while submerged. Divers have, of course, operated out of submarines to do things like placing taps on underwater cables or recover equipment, but those require special handling equipment and a dry shelter on the deck for ingress and egress, and the divers spend months training to do particular operations. Moving bulk cargo while submerged would just be an enormous risk for no good reason. Stranger ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [September 22, 2021, 6:27pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/26 "2021-09-22T18:27:53Z")
> [@robby](#): > > Nuclear subs make their own potable water (via desalinization) and oxygen (via electrolysis of the desalinated water). Carbon dioxide is also scrubbed out. On the SmarterEveryDay YouTube channel, Destin has a series of videos in which he spends time aboard a nuclear sub. Rather than electrolysis, at one point he shows the crew burning an “oxygen candle” to adjust the O2 concentration in the sub: > **[Chemical oxygen generator | Oxygen candle](https://en.wikipedia.org/wiki/Chemical_oxygen_generator#Oxygen_candle)** > > A chlorate candle, or an oxygen candle, is a cylindrical chemical oxygen generator that contains a mix of sodium chlorate and iron powder, which when ignited smolders at about 600 °C (1,112 °F), producing sodium chloride, iron oxide, and at a fixed rate of about 6.5 man-hours of oxygen per kilogram of the mixture. The mixture has an indefinite shelf life if stored properly: candles have been stored for 20 years without decreased oxygen output. Thermal decomposition releases the oxygen. The burn... ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [September 22, 2021, 8:27pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/27 "2021-09-22T20:27:00Z")
> [@Machine\_Elf](#): > > > [@robby](#): > > > > Nuclear subs make their own potable water (via desalinization) and oxygen (via electrolysis of the desalinated water). Carbon dioxide is also scrubbed out. > > On the SmarterEveryDay YouTube channel, Destin has a series of videos in which he spends time aboard a nuclear sub. Rather than electrolysis, at one point he shows the crew burning an “oxygen candle” to adjust the O2 concentration in the sub: > > [Chemical oxygen generator - Wikipedia](https://en.wikipedia.org/wiki/Chemical_oxygen_generator#Oxygen_candle) I didn’t watch the video in question, but our normal procedure was to simply bleed oxygen as needed into the ship’s atmosphere from the high-pressure oxygen storage tanks. The electrolytic generators were operated near-continuously to keep the O2 storage tanks topped off. (The only time the generators weren’t operated is for maintenance or drills.) Fun fact: the oxygen generators used electrolysis to split water molecules into gaseous oxygen and hydrogen. The oxygen was stored while the hydrogen was expelled overboard. So you had gaseous oxygen, hydrogen, and lots and lots of electricity. What could go wrong? 😏 Did I mention we called the oxygen generator the “bomb”? 😉 Anyway, the only time you’d need to use oxygen candles is if the oxygen generators were down for an extended period of time and the storage tanks were getting low. The candles were basically emergency equipment. Similarly, we had carbon dioxide absorbent consisting canisters of lithium hydroxide that was also for emergency use. It could be that a submarine crew might use oxygen candles for practice, or to rotate stock, or maybe their oxygen generator was down for an extended period of time, but I don’t recall ever using them. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [September 22, 2021, 8:32pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/28 "2021-09-22T20:32:57Z")
AIUI, some of the Kursk submariners kept burning oxygen candles to survive as their compartment was half-flooded with water. Eventually they suffocated anyway. ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [September 22, 2021, 9:36pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/29 "2021-09-22T21:36:46Z")
Actually, the oxygen generating cartridges probably brought a swift end to the survivors in the ninth compartment: > [@](#): > > Salvage team members found a large number of potassium superoxide chemical cartridges, used to absorb carbon dioxide and chemically release oxygen to enable survival, in the ninth compartment. Autopsies of the crew recovered from the ninth compartment showed that three men suffered from thermal and chemical burns. Researchers concluded Captain-Lieutenant Kolesnikov and two others had attempted to recharge the oxygen generation system when they accidentally dropped one of the chemical superoxide cartridges into the sea water slowly filling the compartment. When the cartridge came in contact with the oily sea water, it triggered a chemical explosion and flash fire. Kolesnikov’s abdomen was burned by acid, exposing the internal organs, and the flesh on his head and neck were removed by the chemical explosion. > > The investigation showed that some men temporarily survived this fire by plunging under water, as fire marks on the bulkheads indicated the water was at waist level at the time. But the flash fire consumed all remaining oxygen, so that the men still alive after the flash explosion quickly died of carbon monoxide poisoning. From Wikipedia: > **[Kursk submarine disaster | Forensic examination](https://en.wikipedia.org/wiki/Kursk_submarine_disaster#Forensic_examination)** > > While waiting for the boat to be brought to shore, a team of military doctors set up a temporary forensic laboratory at the military hospital in Severomorsk. After Giant 4 was floated out of the drydock, water was drained from the drydock, exposing the Kursk's hull. Salvage teams cut into the compartments to drain water from the interior. Ordnance teams removed the missiles from outside the hull. On 23 October, two investigators and two navy commanders were the first to enter the hull. The next d... ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [September 22, 2021, 9:51pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/30 "2021-09-22T21:51:47Z")
Or you can do what the San Juan did [twice] - hijack the supply run of an arctic expedition, then go back and take their resupply when it arrived … not quite doing it underwater, but resupply without actually going into port =) ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [September 23, 2021, 7:07am UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/31 "2021-09-23T07:07:36Z")
> [@gnoitall](#): > > But the flash fire consumed all remaining oxygen, so that the men still alive after the flash explosion quickly died of carbon monoxide poisoning. I was curious as to why they would have died of carbon monoxide poisoning and not simply asphyxiation (i.e., lack of oxygen in the breathable air). After browsing Wikipedia for a while it turns out that asphyxiation kills you in about seven minutes, whereas breathing a 1.28% concentration of carbon monoxide kills you in less than three. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [September 23, 2021, 10:21am UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/32 "2021-09-23T10:21:28Z")
> [@psychonaut](#): > > I was curious as to why they would have died of carbon monoxide poisoning and not simply asphyxiation (i.e., lack of oxygen in the breathable air). After browsing Wikipedia for a while it turns out that asphyxiation kills you in about seven minutes, whereas breathing a 1.28% concentration of carbon monoxide kills you in less than three. If the inhaled gas is truly oxygen-free, then victims are rendered unconscious after just a few breaths, same as breathing normal air with 1.28% CO. > **[Inert gas asphyxiation](https://en.wikipedia.org/wiki/Inert_gas_asphyxiation)** > > Inert gas asphyxiation is a form of asphyxiation which results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen, rather than atmospheric air (which is composed largely of nitrogen and oxygen). Examples of physiologically inert gases, which have caused accidental or deliberate death by this mechanism, are argon, helium, nitrogen and methane. The term "physiologically inert" is used to indicate a gas which has no toxic or anesthetic properties and do Ac... ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [September 23, 2021, 10:30am UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/33 "2021-09-23T10:30:33Z")
> [@Machine\_Elf](#): > > If the inhaled gas is truly oxygen-free, then victims are rendered unconscious after just a few breaths, same as breathing normal air with 1.28% CO. Yes, that’s the same article I found, and the one which states that death occurs after seven minutes. Exactly when consciousness is lost isn’t particularly relevant to the claim about what killed the Kursk submariners. ---
**Author:** ![Martin\_Hyde](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@Martin\_Hyde](https://boards.straightdope.com/u/Martin_Hyde)\ **Post date:** [September 23, 2021, 6:21pm UTC](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109/34 "2021-09-23T18:21:31Z")
The Russians being secretive especially about disasters that were an embarrassment to Putin haven’t fully shared a lot of the details of that disaster, but I also think in some of the compartments they explored during the recovery it was found the CO2 levels were higher than they would have been just from human respiration, suggesting something was burning etc as well. [Previous page](https://boards.straightdope.com/t/can-submarines-be-refuelled-or-resupplied-under-water/951109.md?page=1)