Powering oil tanker with airprops (is it possible)?

[AlexPl]

Hi, i'm not sure if this is the best place to ask this. I've been lately preoccupied with the noise we are creating by using underwater propellers in shipping, and i think its one of the hugely important issues we need to solve somehow. How big (and how many) propellers are needed to power a tanker/freight ship? Is this ways of thinking practical at all? I know that the airprop should be 1000 bigger (or rotate 1000 times faster) than underwater one, so we are probably not talking one enormous propeller, but rather some propeller array. Any advice would be greatly appreciated.
As an example? i have found that propellers on cargo ships are roughly 6-9m in diameter and spin at around 100 rpm.

[Striker543]

I’m no engineer, but I don’t think this is practical for many reasons. A few are: 1) yes it will be quieter underwater, but the noise to power a tanker with air props will be unbearably loud above water; 2) you will lose reverse, which ships need; 3) it is probably a lot more expensive in fuel since it takes more power to move a ship with an air prop than it does with a water prop., etc.

[AlexPl]

I’m no engineer, but I don’t think this is practical for many reasons. A few are: 1) yes it will be quieter underwater, but the noise to power a tanker with air props will be unbearably loud above water; 2) you will lose reverse, which ships need; 3) it is probably a lot more expensive in fuel since it takes more power to move a ship with an air prop than it does with a water prop., etc.

These reasons may be remedied, imho. But probably not in retrofit. 1) using electric engines. The only noise will be from the blades hitting the air. (How loud is that, btw?) 2) that can be either done by underwater prop (i think its acceptable to use such technology for reverse as it is 0.01% of ships movement, i guess) or rotate airprops around their axis. 3) it probably would be, i'm almost sure of it. But nothing is done without sacrifice. If fuel is sustainable/renewable (hydrogen) - that might not be a big issue.

[Junker]

[digginfool]

I’m no engineer, but I don’t think this is practical for many reasons. A few are: 1) yes it will be quieter underwater, but the noise to power a tanker with air props will be unbearably loud above water; 2) you will lose reverse, which ships need; 3) it is probably a lot more expensive in fuel since it takes more power to move a ship with an air prop than it does with a water prop., etc.

These reasons may be remedied, imho. But probably not in retrofit. 1) using electric engines. The only noise will be from the blades hitting the air. (How loud is that, btw?) 2) that can be either done by underwater prop (i think its acceptable to use such technology for reverse as it is 0.01% of ships movement, i guess) or rotate airprops around their axis. 3) it probably would be, i'm almost sure of it. But nothing is done without sacrifice. If fuel is sustainable/renewable (hydrogen) - that might not be a big issue.

So, I get where you may be coming from but the reality is that air propulsion will be vastly inferior to water propulsion for two very simple reasons; density of the propulsion medium, sound. First, water is way denser than air and non-compressible. This creates a far more efficient conversion of horsepower to thrust. Second, air propellers are incredibly noisy and the size and number that would be needed to move a ship would be absurdly noisy. That's assuming you could create enough thrust with the comparatively low density and compressibility of air. It's not even remotely feasible.

[AlexPl]

I’m no engineer, but I don’t think this is practical for many reasons. A few are: 1) yes it will be quieter underwater, but the noise to power a tanker with air props will be unbearably loud above water; 2) you will lose reverse, which ships need; 3) it is probably a lot more expensive in fuel since it takes more power to move a ship with an air prop than it does with a water prop., etc.

These reasons may be remedied, imho. But probably not in retrofit. 1) using electric engines. The only noise will be from the blades hitting the air. (How loud is that, btw?) 2) that can be either done by underwater prop (i think its acceptable to use such technology for reverse as it is 0.01% of ships movement, i guess) or rotate airprops around their axis. 3) it probably would be, i'm almost sure of it. But nothing is done without sacrifice. If fuel is sustainable/renewable (hydrogen) - that might not be a big issue.

So, I get where you may be coming from but the reality is that air propulsion will be vastly inferior to water propulsion for two very simple reasons; density of the propulsion medium, sound. First, water is way denser than air and non-compressible. This creates a far more efficient conversion of horsepower to thrust. Second, air propellers are incredibly noisy and the size and number that would be needed to move a ship would be absurdly noisy. That's assuming you could create enough thrust with the comparatively low density and compressibility of air. It's not even remotely feasible.

Thank you. The only option left is sail then ) I can wait longer for my goodies, not a big problem.

[kwanjangnihm]

https://commons.wikimedia.org/wiki/User:Alexpl

https://www.youtube.com/channel/UCemegT ... o8PZvp5AXA

[Slidin Gator]

I sure smelled troll on this one. If in/under water propulsion is inherently noisy, then we could not call our submarine force the "Silent Service"?

Just imagine a drastically scaled up 1000 foot version of this pulling into the Panama Canal. Sure would help get rid of some of those pesky Sea Gulls for sure.

[AlexPl]

https://commons.wikimedia.org/wiki/User:Alexpl

https://www.youtube.com/channel/UCemegT ... o8PZvp5AXA

Hey, that is some mighty investigative power )) Do you think that any "John" coming to this forum will be the same person?

[AlexPl]

I sure smelled troll on this one. If in/under water propulsion is inherently noisy, then we could not call our submarine force the "Silent Service"?

Just imagine a drastically scaled up 1000 foot version of this pulling into the Panama Canal. Sure would help get rid of some of those pesky Sea Gulls for sure.

Yep, judging from your communication ethics(probably the same for the rest of your interactions with the world) i think i have heard enough. Some people are looking for solutions asking questions, others bury their head in the sand and continue with their lives like business as usual.(and insult people casually for no reason, that's one of the trademarks of this crowd. Just to put your great minds at rest - Alex Polyenov, that is my real name (hence PL). Nothing to do with that cartoon channel Sherlock posted above.
And underwater noise from propellers (from cavitation bubbles implosions mostly) is an issue on which there is scientific consensus - that we know very little but from what we know it is having a big negative impact on the whole marine ecosystem. And its increasing at unprecedented rate. So basically a very parasitic (no one apart from us benefits while everyone else suffers) action on a global massive scale, like cancer.

[Deano]

. . . These reasons may be remedied, imho. But probably not in retrofit. 1) using electric engines. The only noise will be from the blades hitting the air. (How loud is that, btw?) 2) that can be either done by underwater prop (i think its acceptable to use such technology for reverse as it is 0.01% of ships movement, i guess) or rotate airprops around their axis. 3) it probably would be, i'm almost sure of it. But nothing is done without sacrifice. If fuel is sustainable/renewable (hydrogen) - that might not be a big issue.

The only thing wrong with your premise is that it completely ignores the first two Laws of Airboat Physics.
Rule #1 : Reality doesn't give a damn about how cost effective, or good, or Green, or Noble you think your intent is.
Rule #2 : Reality will not yield to ANY LEVEL of ignorance or stubbornness, now matter how extreme.
If your thought process were defensible or could be implemented . . .
we would all be running dry across sticky green grass at high noon with our whole family on 32' airboats that slept 6 people powered by 18 hp Briggs & Stratton engines that had no need for a gearbox because the new technology pixie dust polymer used for manufacturing propellers allows an increase of thrust by 3.14159265359^9 running at direct drive RPMs (while only producing 32 decibels at 25 feet).

FFS

The only option left is sail then, I can wait longer for my goodies, not a big problem.

Please realize you very likely will not live that long.
Take the gross tonnage of the Nina, or Pinta, or Santa Maria and take the square feet of sail their rigging carried.
Calculate the square feet of sail required to move each ton.
Multiply that number by the number of tons your loaded oil tanker is displacing.
Now with your sq/ft of sail requirement and your ship's dimensions in hand, you can go to a sailboat forum and get the help you seek.

[AlexPl]

. . . These reasons may be remedied, imho. But probably not in retrofit. 1) using electric engines. The only noise will be from the blades hitting the air. (How loud is that, btw?) 2) that can be either done by underwater prop (i think its acceptable to use such technology for reverse as it is 0.01% of ships movement, i guess) or rotate airprops around their axis. 3) it probably would be, i'm almost sure of it. But nothing is done without sacrifice. If fuel is sustainable/renewable (hydrogen) - that might not be a big issue.

The only thing wrong with your premise is that it completely ignores the first two Laws of Airboat Physics.
Rule #1 : Reality doesn't give a damn about how cost effective, or good, or Green, or Noble you think your intent is.
Rule #2 : Reality will not yield to ANY LEVEL of ignorance or stubbornness, now matter how extreme.
If your thought process were defensible or could be implemented . . .
we would all be running dry across sticky green grass at high noon with our whole family on 32' airboats that slept 6 people powered by 18 hp Briggs & Stratton engines that had no need for a gearbox because the new technology pixie dust polymer used for manufacturing propellers allows an increase of thrust by 3.14159265359^9 running at direct drive RPMs (while only producing 32 decibels at 25 feet).

FFS

The only option left is sail then, I can wait longer for my goodies, not a big problem.

Please realize you very likely will not live that long.
Take the gross tonnage of the Nina, or Pinta, or Santa Maria and take the square feet of sail their rigging carried.
Calculate the square feet of sail required to move each ton.
Multiply that number by the number of tons your loaded oil tanker is displacing.
Now with your sq/ft of sail requirement and your ship's dimensions in hand, you can go to a sailboat forum and get the help you seek.

I'm not sure how you interpreted what i have written, i thought that was pretty straigtforward... I've not made any assumptions, I'm just probing the reality. That was the real question about the noise from the propeller, i suppose if that was the only way to answer imaginable its fine.

As for sail cargo - i haven't even tried to say that it would be cheaper or that we should ship the same amount around the world we do now using that method. I'm happy to pay premium on shipping, and i do not really need that much stuff shipped by sea anyway. Obviously there is this group of people (fortunately a dying breed, its a tough sell for younger generations ), that thinks that business is as usual and there is no need to change current practices of conducting of our affairs. And i didn't mean putting sails on tankers? btw (although it would be interesting to calculate the dimensions. 1sq m of sail is something like 1kw of power, i think (in decent wind). The fleet should be built from scratch, in this case. There is already a project that is building sail cargo ship? half way into making. I would readily switch to something like that even if it means longer delivery times (prices probably be the same considering that fuel is out of the equation for now).

[OneBFC]

Right, you have a ton to learn.

My suggestion is to enroll in a general engineering undergraduate program before burning much more on this. Sprinkle in a couple finance courses from a business major while you are at it.

I see you write many times, "I am willing to pay...."

Well, you are probably rich by most of the world's standards and wouldn't be impacted by the cost of your goods doubling or tripling.

New flash, everyone else will be sensitive to that.

And what is the reason for the massive cost increase? Unsubstantiated claims that its too loud under water and it has some, thus far, untold impact on untold under water life form(s).

Noone is going to take you seriously at this rate. Rightfully so I might add.

I have an extensive background in many engineering disciplines. My favor to you is to say your ideas are pure fantasy and to find something else to spend the hours of your life on that will have a better chance of a positive outcome.

Given how the world is these days, you will likely take offense to my advice. Not much I can do about that.

[AlexPl]

Right, you have a ton to learn.

My suggestion is to enroll in a general engineering undergraduate program before burning much more on this. Sprinkle in a couple finance courses from a business major while you are at it.

I see you write many times, "I am willing to pay...."

Well, you are probably rich by most of the world's standards and wouldn't be impacted by the cost of your goods doubling or tripling.

New flash, everyone else will be sensitive to that.

And what is the reason for the massive cost increase? Unsubstantiated claims that its too loud under water and it has some, thus far, untold impact on untold under water life form(s).

Noone is going to take you seriously at this rate. Rightfully so I might add.

I have an extensive background in many engineering disciplines. My favor to you is to say your ideas are pure fantasy and to find something else to spend the hours of your life on that will have a better chance of a positive outcome.

Given how the world is these days, you will likely take offense to my advice. Not much I can do about that.

No offence taken.
I've studied Finance (among others) during my second degree, btw, i'm aware what you are trying to prove. Only you are not taking into the account emerging consciousness evolution (nothing metaphysical, just my generation (and subsequent one, like Greta Thurnberg generation) view on reality, removing oneself from egocentric view of the world, rejecting predatory, bordering on criminal brand of capitalism.)

I'm sure to the people who view the world from your point of view its all nonsense, but nonetheless. Many of us are willing to pay more for organic, give up meat (or substantially reduce consumption, and make many other sacrifices to fix the creeping problems last couple of generations left us with. Yes, aging trumpian elite with their worldview will be here for some time, they have nothing to offer us though. I'm not rich, yet i do make choices that cost me more in order to fix the problems few generations of mindless spending created. Yes, if you take an average primitive human being from a third world country - your theory pans out. There are such individuals in developed countries as well not a majority anymore, thankfully.)
The idea i had about props may be fantasy (it often happens with ideas), that is why i came to the place where people know about props to get some info. Sail power is a proven technology though, something i know quite a bit about and i'm ready to accept its limitations. With decentralized manufacturing coming sea shipping will not be such critical industry.
So far i haven't met anyone that interesting with such a take on reality, i have couple of close older friends (over60 and over 70) who lived like that their entire lives, "movers and shakers" (people who have wikipedia entries about them), although they are steadily shifting their views and have ditched that mid 20th century mentality for the most part.

[Rick McC.]

^^^^ You lost any shred of credibility you might have had several posts back; and you definitely crashed and burned at ‘Greta Thurnberg.”

[Gary S]

I'm sure to the people who view the world from your point of view its all nonsense, but nonetheless. Many of us are willing to pay more for organic, give up meat (or substantially reduce consumption, and make many other sacrifices to fix the creeping problems last couple of generations left us with. Yes, aging trumpian elite with their worldview will be here for some time, they have nothing to offer us though.

You have come to the wrong place here. Not a lot of PETA fans sitting in momma's basement polishing participation trophies on this forum.
Love to here a blade push some water.

[Deano]

^^^^ You lost any shred of credibility you might have had several posts back; and you definitely crashed and burned at ‘Greta Thurnberg.”

I smelled that one coming; hence the 'or Green' inclusion in my post.

Greta's dad should've been charged with Child Abuse for what he allowed, where she is concerned.

[Prototype]

My answer is no.................
I haven't read anything below the ops question but I do have insight into the question itself.
Even in diesel format and wind tunnel props, Id say learn to drive or hire a harbor pilot or tugs.
I sure hope this is a joke regarding tankers from other countries and sea captains looking for air power?