Submarine Secrets: What Stops Subs Sinking But People Overlook?

Submarines have something called Sacrificial Anodes. These small details are important to stop the submarine destroying itself. Yet, few people know about these. Unscripted and unedited, just raw knowledge sharing

[@AsbestosMuffins]

an interesting side note, museum ships and subs on the great lakes and in freshwater rivers actually need a different cathodic protection system, the saltwater anodes will actually eat the hull. the USS Cod recently showed this when they drydocked

[@HISuttonCovertShores]

interesting, wasn't aware

[@thomasshoe92]

Aluminum or freshwater

[@Shadow__133]

Since they are static, can't the hull be covered with a resin or even a hard cover plastic/fiber outer hull?

[@Marci124]

@@Shadow__133 It would need to form a watertight seal, at which point you're just building another hull around the ship. Replacing a relatively standard part is easier I guess.

[@Shadow__133]

@@Marci124 Thats what I meant. For my inexperienced head it sounds easier to do that once, instead of restoring the hull and change sacrificial metals routinely.

[@ibbylancaster8981]

I appreciate how it is basically we’re sitting around a pint or cup of tea and you are just chatting with us like we’re just a couple of folks talking with an extremely interesting and intelligent person. You never pander for likes or promote yourself at all. Thank you Mr Sutton. Have , or , are you able to do something on the Virginia class. I have lived in North Carolina all of my 51 years. I have been on the Battleship North Carolina many times over the years and I know that she’s passed along her name to SSN 777 I have watched many videos over the years but I wouldn’t mind one of your reviews 😉

[@brucegibbins3792]

Very few sea craft are without sacrificial anodes. Without these all most other metal features corrode and the fix is expensive to say the least. The detail for this is succinctly presented here. My own experience is only with smallish day launches, never thinking that the same problem is experienced so widely. Thank you for another excellent programme. I'm learning such a lot.

[@riskinhos]

many are. actually most are. ever heard of fibreglass?

[@ryanzwiep1162]

I always find these videos very interesting. Thanks again.

[@Soullessfpv]

I am a project Coordinator for a company that specializes in cathodic protection. We manly work for gas companies protecting the underground gas lines. These are all coated one way or another but even these need to be protected by either galvanic or impressed current. Also, while your explanation of galvanic corrosion is correct with different metals causing the corrosion. The steel hull would still corrode by itself due to deviantions in the metal itself being in the salt water. Think of any unprotected piece of steel left outside. Rust is a form of corrosion. Great video still. Love learning from all your videos and Aaron's Sub-briefs

[@robr2389]

Another interesting video!! Thanks! The USN submarines I was on all had sacrificial zincs aft. As I remember, I think they were all below the waterline. They sort of melt like ice cubes. Only at a very slow rate. Remember reading that corrosion is an electrical process when water gets between two dissimilar metals there's current flow.

[@bassmechanic237]

Ohio class has a shit ton of them in the top super structure behind the sail. It's cool to see them new before a patrol and then see them half gone with white chalky substance covering them after you get back from patrol. Neat video.

[@kreterakete]

Big hugs from bohemian forest. I adore your knowledge and your will to share it.

[@emmabird9745]

You don't just have to protect against different screw to hull materials. Galvanic corrosion occurs when, in the presence of an electrolyte and oxidant (sea water would be great) a current flows from a higher potential to lower (electrons go the other way). Steel is made up of several different elements each of a different electro potential so that a current can flow between points on the surface of the same plate. We can reduce that by passivation, which is a process by which the alloying elements at the surface are etched away leaving a single element surface. When the steel (actually all metals) are stressed then a varying electro potential occurs throughout so that current can flow between high and low stress. A really good example is welds because when the weld metal cools it locks in stress so if not normalised (reheated and allowed to cool slowly) they rust badly. Protective treatments (like galvanising (zinc plating)) help, paint helps but in both cases they are often compromised by collision (with the dockside?) and the flexing of the structure (in this case hull). Stresses are also produced by hull flex (including external pressure when diving) which also produces potential cells. Corrosion does need an oxidant so deep under water you are safe but nearer the surface not so, which is why the waterlines of surface vessels rust so bad. So sacrificial anodes are useful everywhere in the hull. Lumps on the outer hull would cause turbulence (is that why you see them as streamwise strips?) and so noise. I guess under the casing is a good place particularly as it is near the waterline. A second hull like fibre reinforced plastic for instance would cause problems for the dockyard mateys when the cut holes in the hull to fit/remove/service equipment.

[@kruelunusual6242]

The screw looked very small on that SierraII....may have been the sheer size of it and the perspective.....Jesus those things are huge.....to think all that is Titanium.....my 16oz Titanium framing hammer cost $120.....holy sh....

[@janetyer7147]

I found this both interesting and somewhat surprising, as I would have thought that most modern submarines would be utilizing a low signature active impressed current cathodic protection (ICCP) system, perhaps separately augmented with passive galvanic sacrificial zinc anodes.

[@mcgherkinstudios]

And no need for draggy, noise inducing anodes strapped to the outside of the hull too.

[@spyran5839]

The newest types do (at least for NATO), but it probably isn’t quite worth it to refit the older models.

[@112chapters3]

Shocking

[@kevincook1018]

Here in US they are vert strict about zinc inspection and replacement on a fixed periodicity. There is also a periodic structural inspection of "known hull defects" to verify no pitting growth or erosion. If this inspection is not complied with, SUBSAFE certification is suspended and the sub becomes a surface ship until requirements are met..

[@everypitchcounts4875]

Another very informative video. Keep up the hard work.

[@rockbutcher]

Great topic. Outboard motors and some vehicles in Canada have had those for just over 20 years now. Vehicle manufacturers have started installing electronic 'black boxes' that bleed electrons to stop corrosion.

[@otm646]

Those magic black boxes do not work. Remember that you need an electrolyte to complete the circuit. Vessels are always sitting in (salt) water. The type of crevice corrosion which causes the majority of the issues in automotive applications is not able to be protected in the same way because that electrolyte is only in a very very localized area.

[@jackoates6418]

On a similar note, could you do a video on how submarines create a watertight seal around the screw shaft? And futhermore, how this is made to withstand pressure at depth? I CANNOT get my head around how this is achieved.

[@kiwidiesel]

Shaft seals are not that high tech, Don't forget boats have shafts in the water also so very common to all marine vessels.

[@fleetcenturion]

It's easy. You just have to feed the shaft seals.

[@kiwidiesel]

@@fleetcenturion Just so we are clear that's feed the seals not club the seals huh? And do not, i repeat do not blow the seals...gets messy.

[@dwelch3114]

I have done it, on 688 /637 boats. It was awesome to do. But you have to have represented by the manufacturer. So it comes down to graphite and a hell of a lot of torque.

[@buckstarchaser2376]

Simply inject a fluid between two seals, and then suck it up on the inner - or both - sides. The fluid that is gathered from the inner side can be re-used, while any fluid that gets out of the outside side will be contaminated with sea water. In theory, a water-based lubricant can perform this task without causing any real pollution. In reality, the military has many waivers for pollution and workplace safety, depending on the circumstances. A surface vessel regularly collects a mixture of waters and oils from its various systems though, and so they can reclaim the outer oil+water and burn it in their sludge furnace (if Chinese, they will probably just dump it overboard in ports and fishing waters of rival countries though).

[@gzcwnk]

I seem to recall they are in the ballast tanks so they dont cause turbulence and hence noise.

[@lokischildren8714]

Wow thank you for a fantastic video I had no idea about this on a submarine

[@andylarner3531]

Thanks for putting this together

[@AsbestosMuffins]

Imagine, a wooooorrrld without zinc!

[@_John_P]

Most of the anodes are inside the casing structure, as part is ballast and part is free flood space. So, you cannot look at the outside of a ship or submarine and conclude they don't have that many, or they are really small, or they don't use them at all. Also, keeping them on the outside comes at a cost in drag, signature and rate of erosion. Modern submarines and ships also use impressed current instead of galvanic blocks.

[@mrkeogh]

You'd imagine that replacing "internal" blocks is pretty labour intensive.

[@_John_P]

@@mrkeogh It varies. Locations that are impossible to access without dry-docking, can be fitted with larger blocks, weighing within 35kg to 60kg each, and/or a greater number of them. Once sufficiently spent, removal is straightforward, although it would normally require erecting scaffolding, and installation would only be possible with lifting gear, but both would be needed anyway for other tasks. Locations that are relatively easy to reach and readily available, but tight and require crawling or walking in a squatting\awkward position, such as underneath the top casing structure, can be fitted with small anodes weighing 5kg to 15kg each, to keep them within the range of manually handling limits and replaced more often, as there wouldn't be a need for dry-docking.

[@TrueSighted]

Interesting. Didn't know that. I always love learning new things.

[@AnonymousAlcoholic772]

You may or may not know what they are but your water heater has one if its electric.

[@Republic3D]

Wow I learned something new today. Thanks!

[@chaoslab]

Always a good day when H I Sutton posts a new video.

[@jeremycunningham7897]

Fascinating! I never knew this - thanks

[@fleetcenturion]

They're actually a zinc/cadmium alloy. If you've ever had to change them, be sure it's noted in your medical record. That dust will kill you!

[@benbaselet2026]

They really use cadmium still? It's pretty bad stuff for biology.

[@fleetcenturion]

@@benbaselet2026 - I can only speak from my own experiences of about a decade ago. I spent an entire summer breathing in that crap, before they bothered to mention it to me. The Navy brass conveniently forgets every kind of safety regulation, when they know you won't see any side effects until after they retire.

[@benbaselet2026]

@@fleetcenturion That's just inexcusable and stupid behavior from them. How are you supposed to be able to trust anything when they deal with people with that mindset?

[@fleetcenturion]

@@benbaselet2026 - Simple answer: Because they make you.

[@benbaselet2026]

@@fleetcenturion You can't make trust.

[@darwinortiz6394]

I really enjoy all your videos. Love how you do them unsubscribe. Keep up the great videos.People like me thank you for all your hard work.

[@The31stcenturyfox]

Actually this answered a question I had about the Sierra's as I had seen the previous photo of the six bladed titanium screw and wondered if the new 7 bladed scewback screws were a bronze alloy or still titanium.

[@Einwetok]

Might just be am economic step=back as something that fits budget wise.

[@The31stcenturyfox]

@@Einwetok Very likely as the two sierra II are the only titanium boats (aside from smaller spyboats) left in the fleet so custom buildings titanium skewback props when you have working brass ones is fiscally irresponsible with little weight added. Also might have ended up thr better material for the job, but I don't know.

[@mandowarrior123]

​@@The31stcenturyfoxI'd reckon with it being extremely difficult to fashion them in the first place. After so long they aren't set up to make one as you would be while building titanium submarines. It'd be a lot more expensive and difficult now than then. They were also more of a test than anything. They'll have good numbers on efficiency, longevity etc. Mitigation has also progressed, inducing current in hulls to reduce/target the galvanic corrosion.

[@kevincook1018]

Besides the corrosion concern with galvanic corrosion, there is a near field electrical signature produced by galvanic couples. Along with acoustic and magnetic signatures this was added to the list of vulnerabilities that an enemy could exploit to activate mines for instance. But becase it was judged a lesser threat than the other two vulnerabilities, galvanic signatures never achieved significant R&D funding.

[@gafrers]

Quality as always

[@mcgherkinstudios]

The reason you might struggle to find pictures of sacrificial anodes bolted to the outside of the hull is because that’s not the only way to do it.

[@wootle]

So interesting thank you. I have a very stupid sounding question and it will show my lack of understanding of Chemistry but here goes: how do just those small blocks protect the ship/sub? Because between the blocks is the unprotected metal. If I use [_____] to represent a block then: [____] [____] [____] [____] So is it that the electrons ONLY go to the blocks despite this arrangement?

[@mmmark8737]

The US SSBNs have a lot of zinc blocks in the superstructure.

[@--Dani]

Makes sense, I have zincs on my mercruiser bravo III, I cant imagine a billion dollar sub not having them. Keep up the unscripted contest, second to none...👍

[@batesvillbilly368]

4:54 I think that's a cleat on the dock.

[@Allan_aka_RocKITEman]

Great video...👍

[@johnhargreaves3620]

Nice little piece, just to add most ships rigs and vessels in sea water and in water with minerals in them, also adjust the galvanic corrosion table by using impressed currents across the hulls of the vessels particularly were you are able to provide a sufficient amount of power in the form of a modifying galvanic current to adjust the differential corrosion rates in your favour - this has become quite a science in the protection of metals underwater and is quite complex. Many high value metal objects particularly submarines use these techniques to improve life spans. (source: Institute of corrosion engineers USA/UK) Kind regards

[@H0kram]

Fascinating.

[@Wannes_]

@H I Sutton, what are the black boxes along the Gotland's hull at 04:53 ?

[@Broken_dish]

can you please make a video about the Virginia class sub i keep hearing its so successful but i didnt notice much difference from the others other than it has a lower test depth witch seems like a disadvantage a video explaining what im missing here would be cool

[@Matt-re8bt]

Thanks very much for this fascinating video. One thing I'd like to understand is why the typical design calls for steel (or I guess Titanium) for the hull and brass for the screw. Why not make from a consistent material?

[@jameshealy4594]

My understanding is that screws are normally cast to get the complex shapes and bronze casts much better than steel or titanium.

[@gouglent]

thanks for the videos :D

[@williameddlewis4625]

can you do a look in to that unmanned craft that washed up in Sevastopol

[@SZarael]

@H I Sutton I have a question which has been bugging my lights out and need an answer if you could provide one: with the X- / Gamma ray satellites that are used in space to search far distant stars is it possible to turn one to face earth and seek nuclear subs like this as these sats detect slightest radiation❓ I would be very interested in this answer - thank you ❗❓

[@Svartalf14]

You mean that just by putting two diffent metals in water (preferably the more conductive salt water) in close enough proximity, a process akin to what is used for electroplating occurs naturally, to the point that the "anode' piece of metal can be corroded into destruction? Thanks for making me a more knowledgeable man.

[@stevenlarratt3638]

I beleive the pod on the Sierra is a steel bolt on unit so would react.

[@jtp0321]

There are steel caskets that have anodes on them. I have seen them out of the ground after so many years and they are effective at drawing corrosion.

[@yon2004]

If we are asking questions, how does the wire on a torpedo work? Why does it break?

[@ph00z00]

very nice. thanks for this.

[@nunya___]

@1:40 . You don't have to be in "sea" water. Any water will do, except for "Pure" water, which won't conduct current (or cause GV corrosion) at all.

[@welshpete12]

An interesting side note . The ancient Romans had the same problem with their wooden ships . Where they had iron fittings . They solved the problem by covering them with lead which would be poured on when molten.

[@allangibson2408]

And the British solved it by using Brass and bronze fittings instead (particularly after the started using copper sheathing to prevent fouling).

[@mandowarrior123]

​@@allangibson2408 copper based materials avoid mould and kills of limpets and other creatures.

[@SkywalkerWroc]

So... why did the titanium Sierra-2 at the end need the sacrificial anodes?

[@HISuttonCovertShores]

Because they gave up on having a Titanium screw it seems

[@polyfoamcoats1650]

Can we also ask questions from here? Because I have a rather unusual one. Do submarines have Schumann generators in them like certain spacecrafts do? Because isolating human beings completely from these frequencies have rather unpleasant effects. But then again, having these frequencies on board might make detection easier as these frequencies are very low.

[@derrickstorm6976]

So an anode can be in any part of the ship and it still affects the entire hull? Or do just some parts get corroded so you don't need anodes everywhere? Edit: OH it's just in the propeller area. This is why physics is so hard to a lot of people, the people teaching it take so many details for granted that they don't have to explain them until after the fact

[@LegioXXVV]

Hello. I'm hoping you might be able to help. I'm building an old Dragon 1/350th scale Ohio class SSBN. Do you happen to have any information on the hull paint scheme for the boats now in service? I have plenty of old reference pictures showing the two tone black and red/orange scheme, but I've been told the hulls are all black/grey now. Hoping you might know.

[@paulpinecone2464]

Something I've always wondered: Navies report a tremendous problem combatting rust. Why don't they generally use sacrificial metals to protect against this? Is there just too much of it? It seems that they could transfer out the expended material fairly often when they are resupplied. I imagine powdered zinc could be used to make it easier to handle. A bit more speculative-- how much current is generated by this electron flow? Would it be useful as an auxiliary power source in a submarine?

[@foreverpinkf.7603]

No, this current is way to small to have a useful effect. Powdered zinc would be better in the anti-corrosion aspect, but you have to use larger areas on the sub; so it adds more weight and has to replaced quite often in form of a coating, disturbing the noise protection by rubber coatings.

[@paulpinecone2464]

@@foreverpinkf.7603 I meant for use in ships not subs. Apparently removing rust is the single most time consuming maintainance task.

[@jebise1126]

i thought only alpha and few experimental were titanium hulls... interesting.

[@Syndr1]

Hi H.i. great question, great answer. Don't forget KZbin let's you zoom in now everybody.

[@mikeray1544]

For small/pleasure boats there is Mercruiser "Mercathode " system, keeps the ionic field in balance-

[@ibbylancaster8981]

Mr Sutton, didn’t you say that most propellers are a usually prime numbers but the Russian boat had a 6 blade propeller. Wouldn’t that be a problem?

[@More_Row]

4:50 . Why is the anode up on the dock?

[@lawless201]

What is a "mercy blow"?

[@richard0crewe]

Are the external anodes directly connected to the hull or connected via a wire? It strikes me that having something connected to the hull and not covered by rubber would defeat noise dampening applied elsewhere.

[@dwelch3114]

they are bolted to the hull firmly, so no movement.! I have worked on a sub and a sub tender for what it's worth.!!

[@491Mystic]

So like the scene in hunt for red October

[@S2HL5UCO]

changed a lot in heat exchangers

[@m.streicher8286]

miss your videos bro

[@NixodCreations]

that's what those are?! I thought they were part of some kind of rear-facing hydrophone array

[@michaelkaylor6770]

It is time indeed.

[@DavidOfWhitehills]

Answer starts at 4:00

[@dr.johannesmunch891]

Of course also titanium subs would have kathodes. You simply can't built everything out of titanium. Auxiliary systems, bushings etc.

[@allangibson2408]

Titanium is highly corrosion resistant in seawater. The Australian Collins class submarines have titanium hull plating over the entire hull with a steel pressure bearing hull under it. The steel is not in contact with the water.

[@PointyHairedJedi]

Ok, so, silly question off the back of the titanium subs, has anyone ever made a submarine hull out of brass?

[@matthewm8021]

Brass isn’t generally a very strong material, so wouldn’t be very beneficial. It also has a higher density than steel, so to get a similar depth as a steel hull you would need to make the hull thicker which would also lead to a very heavy boat. Titanium is a good option because it is strong and light, but it is expensive.

[@1337flite]

@H I Sutton - do you have any thiughts about the recent (today is 28 Sep 2022) Nord Stream gas pipeline leaks - three of them - in the Baltic Sea?

[@mblaber2000]

Making sure to close the screen door…

[@bigsarge2085]

👍👍

[@Bane_Diesel]

I asked about this months ago. Mainly I couldn't find good images for it. Clearly you did lol.

[@laavos]

So, why are screws made out of bronze instead of steel? Why do the Russians use titanium ones on some ships?

[@zoperxplex]

Probably has something to do with weight.

[@stevepirie8130]

Cost and ease of repairing.

[@kreterakete]

There is a vid bout titanium subs. Check it out.

[@nomar5spaulding]

What's odd to me is to see those Soviet/Russian boats with left hand turning screws.

[@Kimjongun999]

It is reasonable to interpret the North's nuclear submarine as meaning an SSB equipped with nuclear warheads and ballistic missiles, and as North Korea's official announcement has always been, it is confusing its opponents with vague expressions and falsehoods. However, it seems true that efforts are being made to increase the weight and range of ballistic missiles mounted on SSBs and to increase the quietness of the platform, and even conventional submarines, North Korea's strength in ballistic missiles, including South Korea, is not satisfactory. It is also true that the ultimate counter for this is a nuclear submarine.

[@oneshotracing2147]

You sure know your stuff. I'd like to see you do a video how Russia right now has all its subs at sea along with China. Lots of em off the coast of America and South America.

[@megafjols]

Sorry to be pedantic, but the metals do not lose ions, they lose electrons :)

[@rockbutcher]

Hmmm. I heard him say electrons.

[@Marci124]

Think about it for a bit, if they didn't lose ions, why would there be any corrosion? There's two sides to the equation.

[@TrojanHell]

WALRUS CLASS

[@TrojanHell]

Seems like it has a relatively small prop, especially considering their stealthy reputation

[@fuhlavaflave]

While I like this video, it is somewhat less spy-ey than usual. According to you, I am one of the few who knew about these - they had anodes on WW2 ships. As always, good footage. But if I had my way, you'd be illuminating the capabilities of the Chinese navy.

[@Idahoguy10157]

The titanium submarines are the Alpha class. IDK if any are still in service with the Russian Navy

[@allangibson2408]

The Australian Collins Class have titanium hull plates too.

[@Idahoguy10157]

@@allangibson2408 ….the entire boat hull?

[@HISuttonCovertShores]

This video is for you kzbin.info/www/bejne/jJ64l617o9t0qtE

[@user-lh1ef1st3k]

hmm carbon fiber screw 😆

[@benbaselet2026]

Hmm.. maybe, but advanced plastics might have some really interesting properties.

[@kevincook1018]

Theoretically, fiber reinforced plastics could be used to tailor acoustic properties and supress radiated noise. Unlike bronze which has homogenous material properties, composites typically have orthotropic properties - e.g. directional stiffness. For instance, wood is a radially orthotropic material.

[@jondrew55]

Fun fact: I have a sub secret in my hot water heater. A sacrificial anode!

[@khimbittle7705]

Since the hulls are steel why not make a steel screw to eliminate rhe problem?

[@zoperxplex]

Probably because of the weight penalty and reduction in efficiency.

[@allangibson2408]

Because even different steel alloys have issues with galvanic corrosion.

[@smoofbrain]

So, I might've misread that as Catholic Protection...

[@tombouie]

taiwan just got its 1st sub

[@riskinhos]

Anechoic tiles aren't made of steel or metal. and many subs are made of titanium. not steel.

[@HISuttonCovertShores]

The rubber isn't enough to prevent it. Currently only a few Russian subs are titanium.

[@76dg15]

obligatory comment for the algorithm

[@lancerolen9414]

Dear H I Sutton and anyone reading i hope all is well. I just want to say that Jesus Christ loves and cares for you. If you haven't done so please accept Him as your savior and Lord. And remember to enjoy and cherish all that is good and right in life for we only get one life and we don't know what tomorrow will bring.