As a Naval Architect, I really wish I had access to these videos when I started my degree. Such a practical demonstration of the theoretical concepts.
@ReflectedMiles2 жыл бұрын
....plus you would have understood how critical it is for large ships to be able to get up on plane if they're going to be any good, especially with efficiency plus speed together. If 590-ton craft can leave the ground supported by nothing more than a gas, what's the hold up? How can we expect planing not to be standard on large vessels? 😊
@krombopulosmichael61622 жыл бұрын
@@ReflectedMiles sounds like you are suggesting hydrofoils. They are not efficient for larger ships. Please note my Naval Architectural degree is focused on plastic bathtub toys.
@EricGoesToShopClass2 жыл бұрын
As a docking tug captain, this is cool to see in exactly the opposite way 😂 Practical demonstration is all we get. Learning pressure zones on different hull forms is a very stressful experience.
@RobBCactive2 жыл бұрын
@@krombopulosmichael6162 No in the video plane speed was beyond the hump speed where the wave peak is at the bow and the trough at the stern, so the engines push uphill in addition to water resistance.
@krombopulosmichael61622 жыл бұрын
@@RobBCactive most ships are not designed for plane speed though, according to the video. It does mention bulbous bows, which are becoming more common.
@davidsellon45802 жыл бұрын
Thanks for the explanation. I've often wondered the same. Years ago, I was on a 42' private vessel crossing the Panama Canal. The Canal obviously has too much traffic to let a puny motoryacht take up an entire lock, so the Harbormaster put us in with a cargo vessel -- large, but sufficiently short to accomodate us both -- for each leg of the trip. On the way up, the big ship entered first, and we behind her. When we reached the lake elevation and that ship fired up her engines, her prop wash was so intense that the only thing keeping us from getting bashed into the sides of the lock were the six lines the Canal staff gave us (delivered by the famous "monkey fist") that held us tightly in the center. Still, all open beverages were immediately spilled. When she got underway and we followed, I was amazed at how quickly she put distance between the two vessels. In no time at all, we lost sight of her. Of course she made it across Gatun Lake in a fraction of the time it took us. The Canal staff knew this would happen, so they had previously scheduled us for a departure with a different vessel. This time, her length wasn't an issue, as they put us in ahead of her, and her bow literally covered the space we occupied. You don't truly get a sense of the scale of these beasts until you have looked straight up from the deck of your boat and seen nothing but metal above your head.
@andresmartinezramos75132 жыл бұрын
The worlds most expensive parasol
@bnease0072 жыл бұрын
It’s hard to imagine taking a 42-foot vessel through the PC. It definitely would’ve been a fascinating and memorable adventure.
@davidsellon45802 жыл бұрын
@@bnease007, it sure was!
@robertu2 жыл бұрын
@@bnease007 Taking any vessel through the first time is memorable and fascinating.
@AllAmericanGuyExpert2 жыл бұрын
I have a ship's bell from the Panama Canal. Weighs about 400 pounds.
@subnormality58542 жыл бұрын
I live 800 miles from an ocean, and yet I find your videos fascinating, including this one. Cheers!
@kevinmccaffrey38072 жыл бұрын
Now try living on the water and never taking a job or learn how to drive big boats and ships and watch these videos. I'm In my 30's and love these videos I wanna change my career. cheers
@TheClintonio2 жыл бұрын
Growing up on an island (and living on another) I've never felt the ocean not relevant. I wonder what it's like to live so far inland.
@ArsyanFirdaus2 жыл бұрын
I live 8 miles from an ocean, and yet still find this videos fascinating.
@Grimpy9702 жыл бұрын
Fuckin' SAME. I'm a landlubber who's lived in the desert my whole life
@dickJohnsonpeter2 жыл бұрын
I live 800 miles from land. I've never even seen the land before.
@hawkeyeted2 жыл бұрын
I spent 23 years on aircraft carriers. Being retired, I now work around a lot of Airforce dudes. None of them believe me when I tell them carriers are the fastest ships in the fleet.
@jpaugh642 жыл бұрын
Yeah, that's not how it works in the video games, either! 😂
@timjohnun42972 жыл бұрын
People see that big wide flight deck and ignore the narrow beam at the water line. Probably understandable I guess
@jpaugh642 жыл бұрын
@@timjohnun4297 😂
@jpaugh64 Жыл бұрын
@@hawkeyeted Why are you angry or surprised that video games are wrong?
@hawkeyeted Жыл бұрын
@@jpaugh64 Why are you here chirping about stuff you know nothing about?
@cyberfutur50002 жыл бұрын
wow, I think this is the first time in my life, where someone used the term "wave length" and is actually talking about waves. (I am an audio engineer with a fable for physics, and I know, that those other waves are waves, too... but you know what I mean) And also, that was an utterly interesting video, thanks, I learned a lot^^
@jaybird12892 жыл бұрын
same but for me light waves/ radiation funny how that feels!
@demacherius12 жыл бұрын
same here - electrical engineer
@barrypope43582 жыл бұрын
Me Too..............I'm a Glove maker !
@prototypeinheritance5152 жыл бұрын
Light and Audio-waves are "real" waves too!
@cyberfutur50002 жыл бұрын
@@prototypeinheritance515 yea, that's exactly what I said🙃
@steelbaron63432 жыл бұрын
4:40 "But of course that isn't the hull story." Proceeds to give talk about the Hull design. Nice.
@dparag142 жыл бұрын
And i thought it was just about momentum
@scose2 жыл бұрын
Really appreciate that this video is pure information. no sponsorship, no Patreon pitch, no asking to subscribe
@b789har2 жыл бұрын
Not for nothing but industrial accident recreation videos are interesting, informative and useful tools to prevent future avoidable accidents
@jorditakarbessy85472 жыл бұрын
Is there something wrong about sponsorship, patreon pitch, and a very humble ask for subscibing?
@scose2 жыл бұрын
@@jorditakarbessy8547 they are not wrong but they get in the way of learning. So it's awesome when a youtuber can make ends meet without them
@mastasolo2 жыл бұрын
Those jet engines on the ship are 100% what I would do If Kerbal had sea fairing vessels.
@hphp314162 жыл бұрын
Trent turbines are used to power both aircrafts and ships
@Digi202 жыл бұрын
in fact there are many ship gas turbines that share most of their parts with airliner jet engines.
@mele29042 жыл бұрын
Some US Navy vessels have turbine engines. Envy? LOL
@CynicalOldDwarf2 жыл бұрын
Have a look at Russia's Ekranoplan flying boats
@anonobot33332 жыл бұрын
That’s what the fishing boat needs 😆
@toddkes58902 жыл бұрын
I was thinking it was due to a ship 2* as long, wide, and tall having 4* the surface area (for drag), yet having an engine 8* as powerful. Didn't think about the wave interference. Good video
@ronblack78702 жыл бұрын
i did too. thought it had to do with how a bigger engine takes more fuel but also the bigger ships caries exponentially more containers.
@sverkeren2 жыл бұрын
@@ronblack7870 Not exponentially, but cubic more containers. Length*Width*Height.
@tinkerman95252 жыл бұрын
A boat twice as long is 8 times bigger. L x B x H.
@LoanwordEggcorn2 жыл бұрын
@@sverkeren A cube power is an exponent.
@dmitripogosian50842 жыл бұрын
This is what interesting is that hull speed is determined by the length of the ship, not area.
@bartbliek4692 жыл бұрын
I used to sail small boats as a teenager, and despite not knowing how any of this worked I remember intuitively feeling the phenomenon of hump speed and planing. Especially the boat 'falling' off the top of a wave, going from planing to hump speed, as a gust of wind dies off. Super facinating to learn how this actually works!
@dmitripogosian50842 жыл бұрын
And then you get on a keelboat, which cannot plane, and it does not matter whether the wind is 10 or 20 knots, you can't move any faster ....
@rydenkaye97352 жыл бұрын
You can plane in keelboats my friend, you just haven’t been racing the right ones!
@dmitripogosian50842 жыл бұрын
@@rydenkaye9735 You need foils for that :)
@davidlabarr2 жыл бұрын
Same thing with adjusting the trim on a power boat. At a certain speed and perfect trim, you can just feel the resistance leave and the boat levels out.
@alberjumper Жыл бұрын
Exactly this
@borysnijinski3312 жыл бұрын
I heard a story about a US navy carrier group deciding to have a drag race for amusement. As expected the smaller ships got the jump at the start, but it was not long before the carrier caught up and passed every other boat…much longer hull length.
@Digi202 жыл бұрын
that must have been the most expensive (amount of oil burned apart from the nuclear carrier) drag race in history!
@jimskywaker43452 жыл бұрын
@@Digi20 probably
@ziggyinc2 жыл бұрын
the Carrier always wins!
@ziggyinc2 жыл бұрын
@@Digi20 it happens every cruise.
@MarsStarcruiser2 жыл бұрын
Well, I suppose they don’t call it plane speed for nothing
@capt.eissaeissa27692 жыл бұрын
As a retired Captain now involved in ship construction I find this presentation fantastic. Thanks for sharing, keep up the good work.
@calummcconnell73132 жыл бұрын
also worth mentioning: the drag force is proportional to the cross sectional area of the ship. by the square-cube law, doubling the scale of a vessel will quadruple the drag, but allow 8 times the internal volume for engines to be put in. thus, if your engines take up the same amount of space, you'll have twice the power, and sqrt(2) times the speed
@martinbraden71102 жыл бұрын
Why is a longer boat faster than a smaller one? Because the front is closer to it's destination.
@jaquigreenlees2 жыл бұрын
You could easily expand this video with the hull shape aspect alone, ldl hulls are faster and lower fuel costs. a good example, an 85' loa motor yacht with a draft of 4 feet designed for displacement cruising. Top speed is 18 knots, cruising speed is 15 knots. 15 knots speed gives her 1,500 nm range on 1000 US gallons of diesel, 18 knots gets you 500 nm from the same quantity of fuel. These same factors are in play with the big cargo ships, yet most people can relate to being told if they slow down by 5 miles an hour they will travel 1000 miles further in their pleasure boat over it's cheaper to ship a 6 week trip than a 1 month trip for your overseas delivery.. *ldl = low displacement length.
@Azettler12 жыл бұрын
500 nano-metres! Wow that's inefficient!
@jaquigreenlees2 жыл бұрын
@@Azettler1 nautical miles
@Azettler12 жыл бұрын
@@jaquigreenlees I knew what the acronym was for and was just bugging. I find it funny that we have two measures of distance that have the same unit label :)
@Bruce-19562 жыл бұрын
I sailed on VLCCs in the '70s and their top speed was 15 knots. During the oil crisis we never sailed faster than 8 knots.
@LauRoot8922 жыл бұрын
Bruce 🧐
@KaptainFuzzy2 жыл бұрын
Informative, no nonsense, and very well structured for my layman mind to understand. You run a phenomenal channel and are a great teacher. Thank you!
@LauRoot8922 жыл бұрын
Yep
@ThomasSteffien2 жыл бұрын
it maybe of interest: the bulbous bow works only at a limited range of speeds, because its wave has to interfere as designed with the normal bow-wave. Cargo ship hulls (including the bow-shape) are designed for a resonable range of cruising speed, to be fuel efficient. Intrestingly you can guess a ships speed by looking at its generated wave lenght at the hull. you only need to know how long the ship is, judge the length of the wave and use the formula depicted in the video to calculate the speed of the ship (through the water) ...
@dirkkarmel52092 жыл бұрын
Your explantion/guess, does not include water conditions. All vessels: would be much better with a nose bulb ! -- Better for control of spin & steering; -- Keeping hull at a reasonable angle compared to the water surface. -- Better dispersing of the bow's wave. ****** >> A Hydro-plane: -- can achieve higher speeds; -- has less danger of flipping over. ( compares to many automobiles that save gas, with 500lb -- 200 kg of cement inside the rear trunk ! )
@lochlanm86842 жыл бұрын
@@dirkkarmel5209 how would adding weight in your trunk improve efficiency??
@rydenkaye97352 жыл бұрын
Dumbest comment I’ve ever read. Try strapping a bulb to any type of Planing hull and let me know how it goes
@happyambush1 Жыл бұрын
Wouldn't it be way easier to just guess the speed than to guess the wave length AND guess the length of the hull to calculate the speed?
@awsalminen2 жыл бұрын
Wow. Great video. I’m completely land locked but totally in love with the ocean. Just amazing information. Mind is blown right now
@LauRoot8922 жыл бұрын
Yep
@PakBallandSami2 жыл бұрын
"If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea" --Antoine de Saint-Exupery
@jamesrodgers31322 жыл бұрын
All of which has nothing to do with the video.
@charliecharliewhiskey94032 жыл бұрын
Probably also assign them tasks and work, or else *everyone* will go to collect wood without thinking about it and you'll deforest the surrounding area.
@duroxkilo2 жыл бұрын
@@jamesrodgers3132 that's like saying poetry has no practical applications :}
@jamesb22912 жыл бұрын
@@jamesrodgers3132 I'm glad I'm not the only one who noticed.
@sclark90112 жыл бұрын
what the fuck is an ark ? Noah
@theVoyage2 жыл бұрын
I've seen a boat running at "hump speed" before, a motor yacht. even to my untrained eye, it looked horribly inefficient, like the boat was trying to climb a hill.
@jimskywaker43452 жыл бұрын
another term for that is transition wake, and yes it's very inefficiant
@HelloKittyFanMan.2 жыл бұрын
In quotes? You don't think that's the real term?
@DemPilafian2 жыл бұрын
@@HelloKittyFanMan. Adding quotes like these usually implies fake, but it can also mean a special or unique phrase. Clearly it's the latter in this case.
@HelloKittyFanMan.2 жыл бұрын
No, @@DemPilafian, it was _not_ clear, because if it was then I wouldn't have asked about it. Do you mean like... emphasis? Because if that's what you're trying to say, then you'd be wrong. Because if that is what you're trying to say, then my reply to that is that no, quotation marks are not emphasis marks, or they would be called "emphasis marks" alternately. That's not now, nor was it ever, their job. How anyone would've ever gotten taught that in some presumed "official" way completely baffles me! Emphasis is already handled by *boldness,* _italics
@DemPilafian2 жыл бұрын
@@HelloKittyFanMan. You should have put your entire 2 page reply inside of quotes.
@Lozzie742 жыл бұрын
Beautifully explained. I’ve heard the waterline length rule touted for years and only recently learned it was due to a longer wavelength of bow and stern waves. You closed the loop for me, easily explaining that the wavelength was itself proportional to speed. Thank you!
@pwnmeisterage2 жыл бұрын
Assuming the ship is travelling against and into waves, of course. More often - for speed and efficiency - it'll travel with the waves whenever possible. Sometimes it'll have to travel across the waves, winds and currents don't always end at your planned destination. Sometimes the waters will be calm. Making the hull bulb counterproductive, if anything.
@jan-seli2 жыл бұрын
I had assumed this was just going to be a fairly straightforward square-cube thing, where the drag on the ship scales with the surface area of the ship but the size of the engine it can hold scales more with the volume
@jpaugh642 жыл бұрын
I would expect the engine size to scale with the economic utility of the cargo ship --- which would scale with it's volume.
@ethribin41882 жыл бұрын
Overcoming the hump speed is mechanically the same as breaking the sound barrier. You wffectivly turn a wave into a straight line, saving tons of energy. But it needs tons of energy to overcome the hump/barrier first. And even then it needs more energy then any speed that doesnt approach thr hump/barrier.
@mele29042 жыл бұрын
There are other ways to defeat the wave effects. Tuning shapes of leading and trailing edges to better suit lamellar flows back into the common plane on the trailing edge is the major factor. Shorter hulls can be made efficient at higher speeds but compromises are often made to achieve other desirable effects. This video however is a good beginner primer for this niche of fluid dynamics.
@jpaugh642 жыл бұрын
I thought as much, and thought of the same analogy. "Needs more energy than any speed that doesn't approach the hump barrier." Every time you accelerate from zero, you're approaching the hump barrier. I know you're talking about it as a limit from Calculus, but how close to the hump barrier does it have to be for that factoid to lose veracity? 70%? 40%? Actually, Real Engineering shows a graph of drag vs mach number, and it clearly shows that mach 1 is a peak, and by mach 6, the drag is significantly lower. He was taking about rockets (which are designed to go faster than MACH 1), so I'm not sure if his graph was generally applicable to hurled objects or not. He was discussing the new startup with rockets whose "first stage" is a centrifugal slingshot. I can't remember the video title.
@8Mev2 жыл бұрын
As a random guy on the internet I have to say this is absolutely facinating so congrats to y'all naval engineers who choose an interesting major
@PakBallandSami2 жыл бұрын
step one: get a big ship step two: apply for boat racing event step three: get rejected step four: say the a big ship is like a boat but bigger step five: they still reject you step six: give up
@nonna_sof58892 жыл бұрын
step seven: try to run it anyway step eight: run aground because the course is to shallow
@matejlieskovsky96252 жыл бұрын
step nine: dredge a deeper race course step ten: get smoked by a hydrofoil anyway
@Vinemaple2 жыл бұрын
Hull shape! When I was in maritime school, this crazy old ex-Navy captain used to tell us, "whatever the question is, the answer's usually hull shape." And it's pretty close to correct, although he didn't like it much when the least-mature adult in the class tried to turn that into a running gag. That ex-captain never could get me to understand hull speed, though, and I never really understood the physics behind planing and the way a small craft's bow rises out of the water at hump speed. Never heard the term "hump speed" before. I've never been able to find this stuff in the American Seaman's Manual, either. But thanks to Casual Navigation, it all makes perfect sense. This is a gem of a video. And then we have the bonus of a big container ship getting up on a plane, and then being fitted with giant jet engines. That made me smile.
@spookynerd_jpg42232 жыл бұрын
Going into this, I thought it would be a matter of larger ships having larger, more powerful engines. That's a really interesting cause, though, and it shows just how much thought goes into every aspect of sailing.
@jpaugh642 жыл бұрын
Well, obviously, larger (or underpowered) engines would have an effect. Also, does this rule work as well for pleasure and military ships, where finding the maximally efficient speed is not the most important criterion? The question at the beginning of his video is not well stated, so I'm not sure exactly what I learned.
@unthenner5519 Жыл бұрын
Exactly! Thank you. Everyone else seems to be going along with this unclear premise without questioning it.
@runakovacs47592 жыл бұрын
I did not know the hull speed formula. It's nice to see it confirming my guesstimated speeds for my D&D ship's speed tho (130 ft 3 masted schooner at waterline, assumed her top speed to be around 12 knots. Which is less than hull speed, but considering wind and stuff it's within ballpark!)
@naciremasti2 жыл бұрын
Still awaiting that tugboat video. It'll be epic. Because tugboats are epic.
@thomashammel76332 жыл бұрын
Very happy about your new pace of publication, especially seeing that the quality of the videos didn't go down a notch! Good work!
@hagstruan11402 жыл бұрын
Every now and again the KZbin recommendation algorithm comes up with a real gem. Subscribed.
@TheErik2492 жыл бұрын
20 yrs ago, My wife and I took a cruise from Vancouver BC to Hawaii on Princess cruise lines. The ship kept a steady spead of 24 knots for 2300 nautical miles to Nawiliwili on Kauai. When we docked, I got a chance to speak with a ship crew member while they were fueling. He said that they burned 800 tons of bunker oil. I told him that the trip was really smooth. He said that they cruise at that speed because its about physics and the hull design. He stated that the ship could go a little faster than that but, it would burn to much fuel. While we were underway ftom BC, we passed a smaller container ship under the Matson flag. Everything that YOU have stated here is CORRECT. Thank you sir!
@thereal_morxy492 жыл бұрын
Finally i understand why my uncle always told me it's better to go fast with the boat so it starts planing!
@drewkelly69672 жыл бұрын
As an instructor of maritime topics, thank you for another video that makes me really think!
@bradleypeterson22082 жыл бұрын
I went fishing a lot growing up with my Dad in our 19ft jet boat, I’d always wondered why the boat pitched and accelerated differently before the boat got on step, and how it would fall off step. this makes perfect sense
@mopsnuf2 жыл бұрын
This was extremely informative! One of my favourites of this channel so far. Very well explained and so interesting.
@OneRandomMicrowave2 жыл бұрын
Perfect timing. I was bored so this is great
@simonmakinson2 жыл бұрын
Brilliant as always. I just really enjoy how he doesn’t talk down to his audience. I learnt something watching this…thank you.
@hoodoo20012 жыл бұрын
Back around 1890 when they were building the first USS Texas battleship an argument ensued with the designer, the Bureau of Construction, and the actual builder. There were worries that the weight calculations of the ship had been in error and the builder suggested that the ship be made ten feet longer but the keel had already been laid (but could have been modified at extra cost). The builder said that the ship would have the added benefit of being faster as a result. However, the argument grew so heated about modifying the ship at this stage that the Bureau of Construction threatened to cancel the vessel due to the added cost...however the builder recalculated the weights and stated that while the lengthening could have added speed, the weights were not an issue so the project continued at the design and the Texas, although having an extremely long build time nonetheless was delivered on it's original budget to it's original design. As it turned out the USS Texas might have used an extra knot or two during the Battle of Santiago in 1898 but the Battle turned out well in any event for the United States.
@CMDRSweeper2 жыл бұрын
Excellent video, I heard the term "Hull speed" but nobody had a good explanation as you put it here as to what happens. Keep up the good videos and knowledge spreading you do!
@antnate5782 жыл бұрын
I love how these videos are extremely educational and are practically like having a real “ship” course.
@Lexoka2 жыл бұрын
Very interesting, and very clear! In case you were wondering whether a longer, more detailed video on this topic would find its audience, know that you'd have at least one enthusiastic viewer.
@oliverwabwire28362 жыл бұрын
It's been short aeons.....till the term "wavelength" made this much sense to me! Thanks a bunch👍
@Dave_Sisson2 жыл бұрын
Informative video. Could you please cover the large, high speed, passenger catamarans invented by Incat in 1990 and developments of that design such as the Austal trimaran you showed at the end of this video? I've always been amazed that craft over 100 metres long can travel at up to 50 knots and still be commercially succesful.
@calvinnyala95802 жыл бұрын
Now that's tax money at work i would like to see
@tfhmobil Жыл бұрын
Drag vs stability. Catamarans and Trimarans are very stable, even they hardly touch the water.
@Dovorans2 жыл бұрын
I was under the impression that the hull speed was the last efficient speed (assuming a slippery hull) before the "wall" of resistance you get as you approach hump speed, due the destructive wave interference outlined in the video. So in the graph it would be found at the bottom of the little dip rather than at the hill before it.
@mele29042 жыл бұрын
You can think of the hump speed as a kind of trailing vacuum effect as an analogy.
@jpaugh642 жыл бұрын
There's a similar phenomenon with the speed of sound. Crossing it causes peak air resistance, but for a plane or rocket that's designed for it, going faster than MACH 1 decreases your air resistance the faster you go. So, for an aircraft, MACH 1 is the least efficient possible speed, compared to any other.
@dfgiuy22Ай бұрын
So how do we get this channel to blow up enough to have the budget to get a commerical carrier to plane just using jet engines? Bro, thats such an awesome idea!
@man_on_wheelz2 жыл бұрын
Great, now you've got me visualizing a cargo ship planing the waves like a speed boat by force of several strapped on jet engines.
@ianprice63232 жыл бұрын
The fastest ship ship I've ever been on was the USS Carl Vincent. We were going WAY faster than the 32 knots Wikipedia says it capable of. Seriously. WAY faster than that. It was mind blowing. Aircraft Carriers can move.
@el.blanco89612 жыл бұрын
I like how you answered the question again but this time with the context of everything we're talking about so the more literal explanation makes more sense. Great way to sum it up at the end of the video.
@Raggandrist2 жыл бұрын
I don’t even like ships, they scare me, but i’m such a geek that i can’t help being fascinated by all the technical elements and math involved. These video’s are amazing for people with a similarly geeky disposition as my own
@jpaugh642 жыл бұрын
Things scare me. Mostly, my fears are real possibilities, however improbable. A wise man told me that voluntarily facing my fears was the best way to diminish them.
@lewisdoherty76212 жыл бұрын
I assume the trough shown in the resistance/speed chart found after Hull Speed must have a name? I don't think it is called "Sweet Spot." This appears to be where the ratio of fuel consumed and time expended in transit would be best for ships.
@Jacob-W-55702 жыл бұрын
you might want to add, that to gain speed you need x times more power, that is a bigger reason why speeds are low. as for a 150 meter ship hull speed will be 29 knots but yet they sail 15. half of it. Also if you sail hull speed, with a wave top at bow and stern and a trough mid ships, you loose alot of stability. (not to mention bending moments that come into play at such situations)
@JarrodFrates2 жыл бұрын
He covers that in another video: kzbin.info/www/bejne/j4G0impmr5qogac
@fukkitful2 жыл бұрын
Yes, the middle of your ship sagging can end very badly...
@N1ghthavvk2 жыл бұрын
I had to laugh out loud when I saw that massive commercial cargo vessel using the engines to start "climbing"!
@DaveSCameron2 жыл бұрын
I really enjoy your work and efforts uploading these, not too technical and not too simplistic. 👍❤️🇬🇧
@alveolate2 жыл бұрын
"A ship is just a hull displacing water." Dictionary of Casual Navigation
@evancarpenter2 жыл бұрын
Wait, so the local min is between Hull speed and Hump speed, but what is the effect of the waves on the boat that makes it face less resistance? It seems like you only talked about the speeds individually, but maybe I missed something I loved the bit about the bulbous bow, I had no idea that’s what that was for!
@Jarrettmonty992 жыл бұрын
So I have no expertise or any knowledge about this subject, so I can't make any claims to the author of the video. BUT on doing a little research what I might ascertain is that the graph is shows applies to only a particular kind of boat (I can't find a similar graph anywhere, although it looks like this is not a hugely popularized field so I might just be bad at googling it). From what I've read, the right around the hull speed is going to be the true local minimum, although perhaps that's where things such as the bulbous bow come in, to stretch that minimum out before ascending the curve. It was an interesting topic to learn though, I'm electrical engineer so I missed out on all the fluid/mechanical goodies so I'm learning all the time on these topics! Let me know if you find out
@artificialowl33262 жыл бұрын
omg, I always wandered and never understood why boats had that feeling during some acceleration/deceleration process... thank you so much!
@johnschwalb2 жыл бұрын
Getting a bass boat on plain is one of the coolest driving experience I have ever had.
@Fanny-Fanny2 жыл бұрын
The big'uns generally tend to have a faster 'hump speed', in my experience.
@TheSwedishSalamander2 жыл бұрын
Now I want to see a cargo ship planing.
@othernicksweretaken2 жыл бұрын
Naval architects in my country had the adage: _Länge läuft_ (loosely translates to length runs)
@Pax_Veritas2 жыл бұрын
All the info I needed about something I have no practical use for. Subscribed
@PeterKocic2 жыл бұрын
I guess something could be said about fuel consumption? I assume the smaller vessels choose to run at a more optimal hull speed because it makes sense financially. Unless, they have a customer willing to pay the extra price for express delivery speed?
@LauRoot8922 жыл бұрын
Hmm 🤔
@1898nc22 жыл бұрын
Me and my dad had almost identical boats the only difference was mine was 45’ where as his was 34’. For years how we couldn’t figure out why my boat was so much faster then his.
@jpaugh642 жыл бұрын
To misquote Einstein, once you've eliminated the identical, the rest --- however improbable --- must be the cause. As a software developer, I've learned never to assume I know _anything_ about the system I'm trying to fix, no matter how much experience I have with it.
@vihreelinja47432 жыл бұрын
but this is surely impossible to scale. they neeed to make a proportional 10x copy of a formula 1 boat and other speed boats to demonstrate the theory. and the power to weight/ size ratio must be equal.
@dirkkarmel52092 жыл бұрын
Glad to see your method of reducing the condition, for the average person to understand. ********* Beyond the hull waves, there are other factors that apply: -- Water surface conditons; -- Wind conditions; -- Water currents; -- Ship's acceleration/deceration. -- Angle against water of ship's bow, VS the ship's stern. In a smaller vessel: these quickly Add up ! --- The vessel, quickly becomes unstable ! --- Can easily flip over, in any direction ! ( Bow going under the Stern, being least likely, frequently does occur during bad ocean conditions ! ) In a larger vessel: -- These factors, are minor; -- Once up to speed, is very hard to change speeds or direction; -- Being longer & heavier, reduced dangers from waves; -- A skilled captain: can even use ocean waves, to their advantage. ( Using less engine power, to reach higher speeds. )
@sleepib2 жыл бұрын
There's also the square cube law. Bigger ships have less surface area and cross section per unit volume, so if the same proportion of the ship is dedicated to engines, you have more power per unit of drag.
@nou54402 жыл бұрын
is hump speed how quickly a ship makes lifeboats?
@quillmaurer65632 жыл бұрын
On a related note, how much of a large ship's drag is from wave drag vs. viscous drag against the ship's hull? I always got the impression wave drag is the dominant factor. Thinking of viscous drag would be another factor in favor of larger ships, at least in terms of efficiency. More volume (mass, cargo volume, displacement) per surface area, assuming a similar shape.
@Kieselmeister2 жыл бұрын
Friction drag increases linearly with speed, wave drag increases with the square of speed. (Hull fouling from things like barnacles involves both, as the additional surface area of the protrusions increases friction, and each additional protrusion generates it's own wave.)
@rydenkaye97352 жыл бұрын
Hull friction barely effects wake lol the waves generated by a individual barnacle are negligible compared to the tons of metal displacing water
@quillmaurer65632 жыл бұрын
@@rydenkaye9735 Hull friction doesn't generate waves, it causes drag by another mechanism. Basically viscous friction between the ship and water causes a layer of water to be dragged along with the ship, which puts energy into the water and thus out of the ship, the engine needing to overcome this. Submarines have this, but don't have wave drag because they are too far from the surface to generate surface waves (hence, per displacement, submarines are actually more efficient, though with obvious other limitations and challenges).
@HulioPalas Жыл бұрын
@@quillmaurer6563 i think a submarine generates waves as well, you just can't see them
@rydenkaye97352 жыл бұрын
My favorite example of this is the j class sailboats which have a design rule to limit waterline length but adapted by adding overhangs that enter the water and increase waterline when the boat heels over
@Kennanjk Жыл бұрын
I have learned much and will now calculate the optimal wake surf speed for my boat thank you.
@cliffcampbell88272 жыл бұрын
Has anyone taken a closer look at ancient sailing ships specifically from around Greece, Rome...basically the Mediterranean area? I noticed that some of those ships had a bow with a 90° square to the natural water flow where a bulbous bow should be. Kind of like a stop sign of sorts, only under water and having 4 sides instead of 6. That big under water square bow seems counterproductive to me but maybe the ancients living in the bronze age knew something about fluid dynamics that are simply beyond me.
@cheveuxgraouh38212 жыл бұрын
It's a ram, it's not made simply to go through water, it needs to go through other ships too.
@cliffcampbell88272 жыл бұрын
@@cheveuxgraouh3821 Below the waterline?...and it was recessed a little behind the keel of the bow or figurehead (the ship I saw didn't have a figurehead). I think it was the Argus I was looking at but not sure.
@annasolovyeva10132 жыл бұрын
@@cliffcampbell8827 yes, so you make a hole in an other ship below the waterline and make it sink
@tamaslapsanszki87442 жыл бұрын
25 knots? Jesus, that's faster than many naval capital ships
@kathibaba76652 жыл бұрын
Not really. Naval vessels are usually designed for 25+ knots nowadays. US nuclear carriers can make 33 knots so a Carrier Battle Group is designed with ships that can keep up.
@tamaslapsanszki87442 жыл бұрын
@@kathibaba7665 those are top speeds, not cruise speeds. Of course top speeds are higher, especially for naval ships that usually have a fleet oiler/replenishment vessel nearby. For example the Kirov class battlecruisers have a cruising speed of 20 knots (nuclear), and Ticonderoga class cruisers have the same cruising speed (gas turbine)
@Electronzap2 жыл бұрын
I'm not surprised. A jet can go literally twice as fast as one of my paper airplanes.
@j_taylor2 жыл бұрын
If your paper airplane airline serves good food, I'd still fly with you. 👍🛫
@lairdcummings90922 жыл бұрын
Nice. I had some inkling of what is working here, but having it neatly encapsulated like this clarifies my thoughts and fills in the holes of my practical observations.
@mayankkumar38332 жыл бұрын
Hump speed 🧐
@southaussiegarbo20542 жыл бұрын
Strap on a few jet plane engines lol
@recklessroges2 жыл бұрын
Just from the thumbnail, I can tell it's going to be something to do with the "motion of the ocean". ;-)
@wildalfred2 жыл бұрын
I didn't ever expected ships to be that interesting. You do an awesome job. Thank you :*
@davewestner2 жыл бұрын
Does a similar thing apply to airplanes? For example, the 747 max speed is faster than the smaller 737.
@chuckaddison51342 жыл бұрын
I would imagine that it would hold true, although the densities of the two fluids are substantually different.
@Dovorans2 жыл бұрын
Kind of, in that increasing the size of the airplane increases the Reynolds number for a given speed, and things at higher reynolds numbers tend to have lightly lower drag coefficients. However, once you're at the scale of a small commuter plane drag from mach effects tends to be what limits your speed rather than the drag predicted for using the kind of incompressible flows the Reynolds number was modeled around.
@Titan6042 жыл бұрын
I expect it is more complicated due to the way air is compressible and the density also varies greatly. It is why jets cruise at high altitudes - high altitude = less dense air = higher speed and lower fuel consumption. There is a trade off, if the fuel used to climb to high altitude is more than what you save by being at that altitude, then there is no point, so shorter journeys may have a lower cruising height than longer ones as they don't spend enough time at high altitude to make it worth while. Concord was much smaller than either, but cruised at higher altitude.
@raypitts48802 жыл бұрын
@@chuckaddison5134 same problem evan if water/air 800 times different.
@f3tsch9062 жыл бұрын
I live in a landlocked country, but i really enjoyed this 👍
@TheKittyClink2 жыл бұрын
I'm not in any kind of naval anything yet I watch every video over time haha. I'm a pilot and I watch ship videos 😮
@ronz1012 жыл бұрын
Good instructional flick for those students and the odd interested outsiders. Getting more tricky handling mass at slower open ocean speeds New England through Midlantic with the new speed limits.
@barrackobama54702 жыл бұрын
Your videos have real peaked my interest into boats and sailing. I've never had any interest before this! I think I'm going to have a ask a friend with a boat to take me out so I can learn more!
@beerjameswvu2 жыл бұрын
The last ten seconds answered the question, and I'm so glad I stayed until then.
@moriatyalpha2 жыл бұрын
Not a physician, live in a landlocked country and barely seen an ocean, but watch these videos Like my life depends on it
@benjamit20022 жыл бұрын
great video, like saying a taller person has a longer stride than a shorter person, and thus walks faster
@erhardbaehni18322 жыл бұрын
Really fun windsurfing..when you are planning the first time you think something is wrong as all " water " resident is gone ..lots of fun now .. 😉🐿️
@aaronchown50082 жыл бұрын
Well there's an answer to a question I never had, I appreciate this new knowledge.
@surfstarcc12 жыл бұрын
I've been boating my entire life and this just blew my mind.
@g.k.16692 жыл бұрын
I live very close to the St. Clair river and frequently watch the Great Lakes freighters over 1000 feet in length and the salties (smaller ocean ships) down to just a few hundred feet as they travel up and down the river and into the Great Lakes. For years I have wondered about the wave pattern as some ships would create a massive wave at certain speeds while others moving at the same speed would produce hardly any waves, yet the same ship would then produce a huge wake at a slightly different speed. I just assumed that it was cargo weight that accounted for this. Usually I notice 3 wake patterns as one comes from the bow, another set from mid ship and the last from the stern. This answered a lot of questions for me. Thanks for the video.
@michallacki94622 жыл бұрын
As a mechanical engineering student I found this video super interesting! Love your content!
@JasperB122 жыл бұрын
Keep up the great work! Love your voice! 😍
@nikolaishriver79222 жыл бұрын
If you ever need content for the best kind of knowledge to bring out at a party, this is it.
@imjashingyou34612 жыл бұрын
I finally understand why my bow in my fishing boat wants to stand in the air just before planning.
@circusitch Жыл бұрын
It’s amazing how so much engineering and math goes into things you normally would think about.
@raven4k998 Жыл бұрын
so dose that mean if you put a bump on a speed boat it would be even faster?
@Newfieboi23 күн бұрын
that thumbnail is wild
@wizardmix2 жыл бұрын
The art of this video is how perfectly you explained this to what amounts to a mathematically challenged mind.
@Mastermachine1002 жыл бұрын
I have no idea how I got to this video or why, but it was quite fascinating!
@aidenfarris2872 жыл бұрын
I like these videos to fall asleep or if I’m sad it might sound weird but there peaceful