Why Don't Metal Ships Rust? 

Two essential rules for all new sailors: If it moves, salute it. If it doesn't move, paint it.

I spent hundreds of hours at sea on tankers busting rust and painting. On roughly 600 foot vessels it's a never ending battle waged by the unlicensed deck crew. You end the day looking like you just did a shift in a coal mine most days.

When i was working on ships the deck crew never stopped needle gunning and painting. Every day was a constant battle against rust. I was a cook and did my best to make sure those guys were taken care of.

It's always blown my mind that sealed sections of hull become completely devoid of oxygen because the steel has absorbed it all to become iron oxide. once there's no more air, the steel can't rust unless more oxygen is introduced. This also means you need to be real careful because people die going into those spaces every year

For anyone who hasn't seen it, look into Laser rust removal videos. It's a spiritual experience. They use infrared lasers, and iron reflects infrared while rust absorbs it - so the rust vaporizes with zero damage to the healthy metal. Absolutely magical.

The answer is: they do. A LOT. In places you wouldn't expect rust to be a possibility.

The look and feel of metal with at least a dozen somewhat uneven layers of paint reminds me of the sea as much as the smell of the sea does.

USS New Jersey's channel has just gone through their dry docking. It's interesting everything they've had to do to keep it un-rusted for the next 30 years. And all the steps they can skip because it's not expected to move, or be in salt water.

Does it need to be painted? Yes. That’s why active ships don’t rust - their crews are constantly working on maintaining them. Cathodic protection also helps, but really, it’s down to good old hard work and care.

ngl the rust chipping is really satisfying

I was an industrial painter. Painted a lot of marine vessels, yes they rust. Zinc bars bolted and grounded to the hull helps.

For anyone that’s interested in this topic battleship New Jersey just came out of dry dock and they have several videos talking about there anodes and new paint work. That’s pretty much the main reason they went into dry dock to replace all that. They have an awesome channel, worth checking out!

The titanic is not simply rusting away, it is being broken down by bacteria in the water that is attacking the iron that form those rusticles. Without those bacteria the ship would last several hundred more years, and would still be more or less intact (minus the damage from when it hit the bottom of course).

My initial reaction to the title is "Oh no, they do. That's what the crew is for!" lol

When I was a kid, one of the coolest things was the navy’s motor torpedo boats. And they were selling a few old ones…and I was excited. Then my father told me the original hull thickness and the current thickness, which was much thicker. I was too young to really understand rust, but he made sure I understood these hulls would require a lot of work to fix.

You showed it but I didn't notice it said. And it bears saying : - Rust is bigger than iron. So when a tiny bit of iron at the bottom of the smallest ding in the paint rusts it swells. And pushes at the paint. And makes the crack bigger. And exposes more iron. Also, this increase in size causes the flaking. Which exposes more iron.

I enter massive oil storage tanks. The old onss are rhe most dangerous because the rust has used up a lot of the oxygen in the air. Lack of oxygen and H2S being present means full SCBA when working

i love coming from a 12h shift and looking at stuff like this wile eating thx for making my day a little better

3:57 galvanized nails? how about galvanized square steel? 😂Intresting video good job.👍

Another approach is to make the ship out of something that won't corrode because the oxide forms a fully protective layer on it (for instance, titanium) or doesn't oxidize at all at normal temperatures (for instance, fiberglass or carbon-fiber). This is expensive (titanium is a real pain to work with), but at some point the expense in materials may be less than the expense in paying for continuous maintenance.

Very nice episode. Topic which was confusing me for a while is clearly explained. Thanks.

There is a good reason the modern (somewhat tounge in cheek) version of the classic HOLD FAST knuckle tattoo of deckhands seen sometimes on Bosun’s mates is BUST RUST written across the knuckles.

literally saw this at work while waiting in line to tour a US Navy ship some minor repairs and repainting done to a cruise ship docked behind it, with the navy ship rusting away in multiple spots where paint wore down as it wasn’t due for a repaint for a couple of months when the ship moved homeports

A similar trick was used on all wooden ships, there pole worms were the risk and to keep the worms out of the brunt of the wooden hull soft wood was put on that was also sacrificial material.

So, are you going to add an another video about why the HMS Warrior is still in existence? She was left out to rot for almost a century!! The first fully iron warship....

There are two important factors how quickly ferrous metals on seagoing vessels rust: Salinity and temperature. The higher the salinity and the higher the temperature the faster the decay. The Titanic e.g. is in an evironment with relatively high salinity but low temperature (usually about 4°C). The worst situation are tropical oceans with high salinity and warm water.

And then there's the Black Sea, which is anoxic, so metals at the bottom have lasted centuries without corroding.

There are also electrical based systems. Battle Ship New Jersey has done a few videos about protection systems. They recently dry docked and used aluminum, I believe, because they have an active system installed underneath the ship.

I am a big fan of this channel. Keep up the good work! Change nothing!

Check out Rust Base coating. It’s the best corrosion protection paint for metal ships. Made in USA.

Actually one of the best channels on RU-vid.

I just had to think of the maintenance cost for the Eiffel Tower. That thing is entirely repainted every 7 years to prevent it from rusting and buckling under its own weight over time, and it's not even at sea.

Read The Last Grain Race by Eric Newby. He was a seaman on a steel sailing ship that went from Britain to Australia and back to get Australian wheat. When there was no other work and the weather was fairly mild, he and other lower-ranked seamen had to chip away excess rust and paint over the exposed steel.

I was very interested to hear mention of applying tannic acid to deal with rust. We boil iron/steel small game/beaver traps in wood chips and leaves to blacken them and assist in rust protection.. very cool to suddenly understand that this technique/chemical process (tannic acid) is way more widespread than I thought.

BOIS WAKE UP CASNAV POSTED!!🚢🛳⛵️

Sacrificial anode is amazing and counter-intuitive. The galvanization doesn't need to cover the entirely of the steel like paint would. Any coatings easilly come off with impacts and scratches.

Very well explained

I was just watching a video from a lobster fisherman where he explained why they were putting zinc sacrificial pieces to the hull of their lobster boat

2 seconds in the video : I work as a welder on a shipyard. they rust. they absolutely do. make no mistake on that. repairing an old frigate right now. rust everywhere.

thats actually nuts, idk how i never new this before.

Annodes are still used in modern ships inside of ballast water tanks

take a shot every time this guy says "anyway"

I bet somewhere there is a bosun trying to figure out how to get a work gang down to the TITANIC to start busting that rust and get paint on it! :)

The SS Great Britain was a screw steamer, not a paddle steamer (hence the "SS" prefix).

I am now thinking about the tens of thousands of barrels of toxic liquids that have been dumped into oceans and seas during the past couple of hundred years or so.

Just uploaded.. happy days 👍👍

I both love and hate fiberglass. It doesn't rust but it's really not fun to repair.

Nice explanation, thanks ⛵

Let’s all give a thumbs up if we think this video deserves more views!

Constant maintenance and painting. The main reason is sacrificial anodes. Like in your hot water heater tank. They go on the hull of the ship and the stuff that would eat the metal of the ship goes after them instead. And when they're eroded away enough they are replaced.

“The Titanic is corroding away at such a rate that it will disappear… one day”. That’s a crazy fast and accurate rate!

This was very interesting

You missed impressed current cathodic protection which all ships have. A power supply is used to create the potentials and the anodes are made of something like titanium which is extremely corrosion resistant. The protection is given without the sacrificial anodes corroding. And sacrificial anodes are still fitted should there be a loss of power as a backup.

My god, 'the Titanic is corroding away at such a rate that it will be gone one day'. That sentence was so useful that you may see the point of it one day.

I actually change the anodes/zincs underwater on small-medium sailboats and powerboats along with cleaning them

Fascinating

somehow forgotten that todays ships are build with marine-steel, stainless steel 316L. Which is an alloy of iron, nickel, chromium and molybdenum. This alloy is specifically developed to withstand salty water.

I didn't expect this video to be this interesting. Could also be the weed.

Next videos in this series: "Why Isn't The Sky Blue", "Why Are Politicians Never Corrupt", "Why Do Wooden Houses Never Burn Down"

Why is SS Great Britain shown as a paddle wheeler? SS Great Britain is a screw ship, Great western was a wooden hulled paddle steamer...

Another word for rust is iron oxide. There are many metal oxides and what they all have in common is that they have "adopted" oxygen atoms to bond with, which of course breaks down the crystalline metal structure they once had. Aluminium oxide, Zinc oxide, Carbon Monoxide/Dioxide, Hydrogen peroxide... They are all elements that have bonded with oxygen, and they all have different effects when they come into contact with other elements or molecules or heat etc. Also, oxygen is formed by Greek/latin words. Oxy standing for "birth" and Gen standing for "giver/producer" and if one wants to have a meaning that we can understand in English, oxygen is an acid. It is THE acid really. Most other acids (aside from fluoride) are made of oxygen and hydrogen compounds. With some form of accelerator like sulfur in sulfuric acid or, H2SO4, meaning it has 2 hydrogen bonds, one sulfur and four oxygen bonds. That's right, sulfuric acid is more than 50% oxygen that is ready to let go of the bonds it has with sulfur and attack most other compounds. The least acidic form of oxygen is when it's simply bonded with hydrogen... H2O or quite simply... water. But, if you add even the tiniest amount of salt (natrium) into the mix you now have a quite potent oxidizing agent, also known as salt water. The "Rust Belt" has it's name for a reason... Every vehicle and most other things exposed (like steel bridges) are rusting away at a rapid pace. Why? Because snow/rain in winter is mixed in with road salt, which forms said corrosive agent known as salt water. The reason ships don't rust is because they are painted in quite THICK and resistive layers of paint. They even used to be quite toxic and some still are when they need EXTRA protection. And they are regularly maintained and painted, all in an effort to keep metals away from salt water. There's another good reason stuff in the desert really only rusts lightly... There's 1, not much moisture in the air, 2 the baking sun evaporates any moisture. Oxygen simply doesn't have a co-reagent to work with in the desert most of the time. Still, the heat from the baking sun WILL accelerate any rusting when it occurs in the desert. Which is why you usually find abandoned vehicles where anywhere water can pool, still is rusted clean through while the rest of the vehicle looks almost pristine. In short, you don't want water to sit in direct contact with any metal for very long and ESPECIALLY not if temperatures are high. Look at your typical exhaust headers/system for evidence of what heat does to metal when water is mixed in. Rust galore! Or should i say oxidation hell?

The flags at 2:26 are waving in the wrong direction compared to the sails.

The ss great Britain is pretty much solid rust. Go and have a look.

I find it funny that "rust" is just "iron oxide". Yet it is the only oxide we gave a special name.

Interesting subject. Thank you. 👍

Like aluminum, iron's corrosion is pretty much self-limiting. A surface film forms and the corrosion goes no deeper. The iron Eiffel Tower isn't rusting away, for instance.

Since you talked about the Titanic, i think you should have also mentioned that corrosion does not occur (or works very very slowly) at extreme depths because of the lack of free oxygen radicals (?) in the water at depth.

Rust is my favorite color.

They also periodically replace large sections of hull that are corroding dangerously close to failure.

Question: at 2:30, as the wind is blowing from aft, pushing the ship forward, how come the flags are blowing towards the stern? 🤔

Depending on the metal you don't even need oxygen for it to corrode, as it's possible to reduce the water directly. This results in the evolution of hydrogen gas, which can affect local pH and make corrosion faster. This is why magnesium is not popular for industrial use. The best way to prevent corrosion is to not allow an electrolyte access to the metal surface, so just keep it dry, even if that means coating it in multiple layers of paint

I’ve owned a few steel boats. Got rid of them because I couldn’t keep up with the interior rust hidden in inaccessible places.

Another great video.

I wish the video was longer because I enjoyed it so much because I learned a lot and I also didn't know that galvanized steel was actually supposed to form a certain layer of surface rust so I had always thought galvanized steel sucked in the past

Wonders of Molybdenum. Added to steel to make A4 stainless steel. I think they're starting to use it in fuel cells too as catalysts.

1:50 To any mechanics or engineers out there, I've always wondered: when you remove rust, you're just chipping away the metal structure, right? It saves the rest of it from the rust, but there's also less metal on the structure, thus making it weaker, right? So my question is: after a certain point of rust removal, when/how do you determine you need to just remove that whole segment of the structure and replace it? Or do you not, and just call the entire thing a loss after a certain point?

I've heard ship welders saying that they are practically doing nothing but trying to weld rust together.

Keep in mind, in salt water iron rust faster

Any examples of ships in drydock where we can see an anode? I have never seen one, but I'm not entirely sure if it should be as visible as the illustration shows.

In Neal Stephenson's Baroque Cycle, some slaves of one of the Barbary states trick their masters, take over, and steal the silver and gold off a Spanish treasure ship. They manage to get to southeast Asia with it, and build a new ship...and put the gold on the hull, to hide it, and to protect the ship from ship worms & barnacles. Kinda expensive, but seems like it'd work. In the story, it works out perfectly--their enemies board the ship, looking for the gold, but can't find it.

you ignored a lot about the titanic. It's rusting extremely slowly and not at all in a lot of places because of lack of oxygen at the bottom where it is. It's a very interesting topic. yea "one day" it'll be gone, but that'll be 20000x longer than any boat near a coast

check out the videos on the battleship new jersey channel. they just spent 2 months in drydock and removing rust and repainting the hull and replacing anodes was the #1 thing they did.

Slight problem, the Great Britain was a propeller ship and not a paddle steamer.

Because for obvious reasons they're very well painted, even to marine specifications 😮

I always felt sorry for it being called "sacrificial anodes" 😂😂😂😂

The hms titanic is runsting. however at as much reduced rate due to the low oxygen content of sea water af those depths. the main reason is is losing its structural integrity is due to iron bacteria which literally eats away at the iron (reacting it with oxygen) for nourishment. this is why pain is still needed on modern ships.

Hot water heaters have a sacrificial rod of magnesium (or some other metal) inside of them. The rod is designed to last about 5 years. After which, the inside of your hot water heater starts to corrode, and eventually it will spring a leak, flood your basement, cost you a fortune, and force you to buy a new heater. Coincidentally, the warranty on your hot water heater is 6 years. :) Oh, and if you have a 12 year warranty on your hot water heater, your heater has TWO anode rods in it. Replacing the anode rod is really simple, and cheap! just go to your local hardware store and look around the plumbing section. The process is as simple as shutting off the water supply, unscrewing the old anode rod and screwing in the new one. presto! you have just added another 6 years or more of life to your heater!

Without watching your video or knowing anything about marine engineering, I would take a guess it has something to do with sacrificial metals or connection to a batteries negative terminal.

Cause it’s painted. Saved you the entire video

Anybody who asks the questions "Why don't metal ships rust?" and "Why is there no rust?" has never been near a metal ship. On freshwater there's always some rust and a year's lack of maintenance results in a ratty looking boat. On seawater a year's lack of maintenance can result in a ship that's a real mess.

I've just finished work experience on a 61 year old ship (God I love Poland) and 75% of our time was spent scraping rust. 😭

Thanks

left unchecked...applies to everything nowadays

and how often is a tanker drydocked for fixing rust and paint? every month? year?

Rust mentioned let's go

I though there was some kind of electric corrosion prevention. Like you apply a small voltage potential to the metal and it prevent it to rust.

Great video. :)

do u think u can do a video similar to the Andrea Doria video of yours. but with the SS Principessa Jolanda 1907. the ship that sank at launch fully furnished

Something something galvanized square steel, something something bolts bottled from my aunt, i knew someone is going to make a joke about this

So why would you put an anode on a fiberglass or wooden hull if there's no metal to rust? Does it protect the hull in some way, or is it only to protect the metal components in the ship and if that's the case then could you attach the anode directly to the engine instead of the hull for instance?