Why are ships painted red below the waterline?

Why are ships painted red below the waterline?


have you noticed how boats both large
and small tend to be painted a different color under the water most often it is
red but actually nowadays you can get almost any color you like
the reason for it goes back to the earliest days of sailing ships back in
those days wooden sailing ships would slowly plot around the world a
combination of their slow speed and rough hull made them an ideal breeding
ground for underwater growth just take a look under a pier you will see the sort
of growth these ships used to suffer we’re talking barnacles worms seaweed
and things like that so what’s the issue well all of these things have negative
impacts on ships over time you get the obvious of things like damage to the
hull itself due to worms and the actual growth then you get issues like the
additional weight that they have to carry around and reduction in maximum
speed due to the extra drag of course on sailing vessels that dragon weight would
impact their ability to sail upwind which would yet further reduce their
efficiency what you need is a way to stop marine life from growing on the
bottom of the hull and this is where antifouling comes in antifouling fairly
obviously is just a system designed to reduce fouling by animal and plant life
on the underwater sections of a boat or a ship early solutions were to place
copper sheets on the hulls of ships the Cutty Sark is a great example of this
and I’ll link to the greenwich maritime museum below if you want to see more
about that the primary purpose of the copper sheets was actually to stop worms
eating their way through old wooden hulls a secondary benefit though is that
the copper would reduce the growth of plant life of course as wooden hulls
were a place by iron worm issues did reduce but they’ve never been eliminated
just look at the leisure industry today and you’ll still see plenty of wooden
hulls around and of course regardless of its construction material we still have
the same old issue of drag caused by the growth of plant life is probably more
important now to keep that under control what were the cost of fuel and
efficiency savings on long passage we still need antifouling to stop a
combination of worms barnacles and weed from growing on the underside of hulls
but instead of using the old technique of copper sheets we now use a form of
paint instead that antifouling paint works on the same principle and actually
still uses copper as a biocide though is mostly cuprous oxide is now mixed in
with the paint rather than copper sheets it’s the natural red color of those
copper oxides that’s led to the traditional red color of antifouling
modern antifouling systems can be broken down into two broad categories hard and
soft soft coatings are designed to wear off over time continuously exposing
fresh biocides as the outer layer of the paint wears off hard coatings on the
other hand are designed to be a lot more durable they’re meant to last a lot
longer as the biocides are released the durable layer of paint remains but of
course the biocides contained in the outermost layer do get used up both
systems work on the same principle they gradually release biocides commonly
based on the chemical element copper the difference is that soft coatings slowly
allow the paint to flake off as well as you can imagine there are
environmental considerations to think of no matter what way you look at it
antifouling releases via cites and possibly paint into the environment that
is one reason a lot of ports don’t allow cleaning of hulls they don’t want the
extra dose of biocides and paint released by the scrubbing process so
what are your other options the cleaners one is to simply use normal hardware and
paint on the other side of the hull but that will result in a lot of aquatic
growth that’s fine on a small boat that you can pull out the water and clean
quite often but is not so great on a container ship running around the world
what would happen if for example a container ship picked up some seaweed in
Asia and carried it into the Baltic Sea where it takes hold and overtakes some
of the native species similar things have happened and do actually continue
to happen though it’s not so much from hull growth because of antifouling is
more of an issue for a ballast water but that’s a topic for another video so
aside from just using no antifouling what could you do there is talk of
systems that slowly use some sort of jelly from the hull the theory is that
as the growth attaches to the hull the
using jelly seeps off and takes the growth away with it
I’ve never seen it in use but if anyone has let me know in the comments below
cuz it’d be fascinating to look into otherwise there are some silicon based
paints that make it hard for barnacles and things to stick to the hull itself
unfortunately these don’t actually stop the growth but it makes it easier to
clean off send that most ports don’t allow cleaning anyway not only because of the
historical antifouling issues both so they don’t want to clean off species
that are not native to the harbor itself the last thing they want is to be
overcome by some sort of invasive weed from the other side of the world anyway
hopefully you’ve enjoyed today’s video and have liked learning about the paint
on the bottom of the hull for more content like this
every other Friday be sure to subscribe right here on the channel until next
time thank you for watching and good bye

100 thoughts on “Why are ships painted red below the waterline?

  1. You can also use bio repellant instead of biocide. Selectope is one of those solutions allowing paints to be formulated without copper.

  2. Youtube… slowly render society useless by robbing users of sleep and productivity in the name of producing “active users” who are then sold for marketing dollars. Am I woke? Nay, just a man who needs sleep.

  3. Yes, why are ships painted red below the waterline? Said no one ever…..in the history of the entire universe. 😪 clicks video

  4. Or are they were painted red so if the ship rolled over, rescue crews could see it from a distance and this is just a 'red' herring. Now that would be useful.

  5. If I understood correctly, then the bottom bits are painted red so that every large boat can leave behind a small trail of something designed to kill sea plants. I guess it's lucky that the world only has one or two large boats and they barely ever get used anyway, especially not along similar routes.

  6. Why to modern ships (or at least ww2 era ships) still have masts? They don’t have sails do they? What’s the point of still having this massive masts other than to fly your flag on them? To me they just look like massive air raid strutting out of ships only slowing them down via drag.

  7. It keeps Rosie o Donnell from thinking they are huge floating zero candy bars, and swimming out and eating them.

  8. I don't know. I think harbours should allow cleaning. Sort of like a gas station. Clean the ships while they load/unload their cargo, and somehow sterilize the entire harbour area. Minimize the interaction between what's inside and what's outside the harbour and kill everything inside, then continuasly clean the harbour floor.

    Or something…

  9. Biosides, a compound added to the paint, has successfully been a protection option for many years. Another option is the use of galvanized bars welded to the inner hull.

  10. Might there be a way to create a clearing process, in dry dock, or even at sea, whereby bursts of high-voltage electric current could be sent through a steel hull which would shock and kill-off the clinging sea life? If necessary, lower portions of the hull might need to be redesigned to electrically insulate that protion which needs this treatment. Nano technology included in paint might facilitate this electric charge scheme.

    Another idea – as I understand the Great Barrier Reef in Australia is in danger by the coral there dying from changing sea temperatures – might the clinging barnacles be killed by raising the temperature of the hull they cling to?

    Another approach might investigate the destructive effects of sound vibration. Owing to N. Tesla's theory that everything has an oscillating frequency at which it begins to disintegrate, perhaps a specific sound-wave frequency could be found which this sea life cannot tolerate. Once known this vibration could be sent through the hull. Such a vibration system, in principle, could also be employed for shedding a ship's sea-ice which accumulates on decks and bulkheads which creates a hazard by weighing down ships sailing arctic seas.

  11. There are some antifouling paints that have tested using hot pepper oils as a way to discourage marine growth. I am not sure they work, though.

  12. I've also heard of electric antifouling that runs a low current throughout the hull and kills whatever tries to attach to it

  13. If you got a smaller boat, cleaning a hull in a harbor is not a big deal. You boat out of the harbor a few thousand feet and there are usually moorings you can buoy up to, don't even have to drop an anchor, and then you can sit there and scrub your hull down, then boat back into the harbor.

    It's a shame how our current methods of antifowling are a bit toxic to our oceans. Lots of products seem to pop up now and again promising new and often cleaner approaches to antifowling, but In my experience none of these alternative products have really shown that they are up to par against a thick coat of toxic bottom paint 🙁

  14. Says "barnacles", shows scallops — oops. Now there's 6.5 million people who think that barnacles look like scallops. Internet unlearning.

  15. Freighters, Cargo container barges, Tankers, park for 5 days off the North Shore, of Oahu, where the city Honolulu is located. The acidity of the water currents can scrub a hull, resulting in another year of sailing before having to be cleaned! I was stationed at Wheeler AFB, in the 1891St Communications Squadron, working in Kunia Tunnel in1969/1970.

  16. Actually red lead was one of the original anti-fouling paints which was better than copper. In fact there was nothing better, BUT rather toxic to all of the ocean environment!

  17. Copper based anti fouling paint use has been illegal in the U.S for 20 years or more. We had to stop painting our crab and lobster traps because of it. Which sucked. Have you ever tried to scrape barnacles off a trap on a moving boat in the Atlantic? I have. On the plus side I made good money scraping hulls while the boat is in the water. Diaphragm air pump and a regulator and I could stay under for hours.

  18. I think I once saw an ad that promoted copper sheets for hulls. Apparently there's a way to deal with electrolytic corrosion, the copper will last forever, and it would be recyclable when the ship is ultimately broken up. I think that lead will work as an anti-fouling surface as well, and this would solve the problem of electrolytic corrosion. Environmental people wouldn't like it, but it might be worth considering. Maersk would probably pay for it easily.

  19. Is it to allow for easy sighting of issues with the hull if someone was to go SCUBA diving..? Just making a guess b4 watching…

  20. Thank you for the quick explanation! It gets very tiresome watching a 15+ minute video on something that takes 5 minutes or less!

  21. I used to sail yachts . one story I was told , and I do not know if it's true or no . Was when single yacht racing became popular . Yachts would just disappear at sea never to be heard of again . One skipper who was between Australia and South America had a very lucky escape , when rammed by a killer whale. The story was there was something in the red anti-fouling paint that they did not like . The paint chemistry was altered and the colour changed to blue . And the problem with killer whales disappeared . As I said , I do knot know if this is so , but it is a good yarn.

  22. A few months ago, I went to GT yarmouth. On the 2nd day there, we went down to the beach to watch the sunset:
    My parents: interested in watching the sunset
    My brother: interested in writing in the sand
    Me: interested in looking at the boats and writing "titanic,Olympic,britannic,lusitania and MAURETANIA" in the sand

  23. Hi there! First if all, thanks for All your content! Isso would like to know why you have removed your colregs playlist?

  24. Robots. Or maybe bubbles cleaning the ship bottoms endlessly. Or something like a type of vibration or small electrical current. ????

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