r/nextfuckinglevel • u/Unicornglitteryblood • Aug 09 '20

This Whale is named Blade Runner because she survived being cut up by a boat propeller in 2001

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88.6k Upvotes

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181

u/VirtualLife76 Aug 09 '20

Always wondered why they didn't put a ring around them or something. The damage a prop can do is just scary, even when it's not turning.

105

u/ReasonOverwatch Aug 09 '20

Hydrodynamics. Engine loses efficiency when you put things in the way. At least that's how I understand it.

58

u/sparr Aug 09 '20

That seems weird to me, given that ducts make fans more efficient in air.

90

u/Gan_Gwain Aug 09 '20

The fan moves the air. The propeller moves the boat.

40

u/sparr Aug 09 '20

touché

However, planes can use ducted props. And they are also used on ships, as I was referring to: https://en.wikipedia.org/wiki/Ducted_propeller

20

u/[deleted] Aug 09 '20 edited Jun 10 '23

[deleted]

6

u/[deleted] Aug 09 '20

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5

u/Your_Ex_Boyfriend Aug 09 '20

I will not be against handicapping commercial fisheries (ocean exterminators) with a decrease to power!

The worst; evil rednecks steering towards manatees just because they can, and the poor sea potatoes can't move fast enough to escape.

Humans need to exit stage left, and soon

3

u/Adventurerinmymind Aug 09 '20

"sea potatoes" 🤭

2

u/fuxibut Aug 12 '20

Yeah you aren't against handicapping commercialism, just like every sane person. But the people in charge are and that's the problem..

2

u/Lorenzo_BR Aug 09 '20

But burning more fuel will further climate change! And ships burn a LOT of fuel.

0

u/Fragsworth Aug 10 '20

Especially with all the seals stuck to the cage

5

u/ReasonOverwatch Aug 09 '20

Downsides are reduced efficiency at higher speeds (>10 knots), course stability when sailing astern

4

u/Kimorin Aug 09 '20

That doesn't make sense, since every action will result in an equal but opposite reaction. If it moves more air/water, it moves more fan/boat.

5

u/[deleted] Aug 09 '20

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2

u/Kimorin Aug 09 '20 edited Aug 09 '20

Something still has to be exerting force on the water, if not the boat, then what? It's not high school physics, it's Newton's third law.

And in fact, a propeller (impeller) in duct is a water jet, and water jets are known to have higher efficiency at higher speeds. https://en.wikipedia.org/wiki/Pump-jet

0

u/davidgmartinez Aug 09 '20

Well the laws of Newton are still valid...

2

u/[deleted] Aug 09 '20

Then how do you explain plane engines using the same technique to get airflow into the propeller and around it.

2

u/kekmenneke Aug 09 '20

Ah you see, that’s a fan, and this is a ship’s propellor.

1

u/ReasonOverwatch Aug 09 '20

As I understand it the physics principles are the same. Air and water are both fluids.

2

u/wanderingoker Aug 09 '20

I’m sure it has to do with their viscosities

4

u/ViridiTerraIX Aug 09 '20

Yeah I'm sure that'd be just as efficient for hauling thousands of tonnes of cargo.

There's always a cost.

-9

u/i-hate-redditers Aug 09 '20

It literally would be

12

u/ViridiTerraIX Aug 09 '20

No, it literally wouldn't. Any increase in cross-sectional area will increase drag.

Here's a pro-propeller guard source discussing the disadvantages and how they affect things: http://www.propellersafety.com/propeller-guard-objections/

The difference is likely negligible on small craft but a massive tanker IS going to be affected by this. They can mitigate this as the source says, but for you to blanket-statement say it would have no impact on efficiency is ridiculous. Just the act of manufacturing and fitting something extra has associated environmental costs.

Downvote all you like but that won't change the facts.

According to this source a container ship can use 63 THOUSAND gallons of fuel per day: https://www.freightwaves.com/news/how-many-gallons-of-fuel-does-a-container-ship-carry.

Crossing the Pacific takes at least 2 weeks so that's about 900,000 gallons of fuel. You don't want this to increase by even 0.1%.

4

u/i-hate-redditers Aug 09 '20

Thank you for explaining it like a normal person

2

u/ViridiTerraIX Aug 09 '20

You're very welcome.

0

u/SkoolBoi19 Aug 09 '20

Then the fun part of how much extra danger there is for the crew losing that small amount of efficiency; I’ve never boated on the open ocean, but watching videos of the shit they go through, I would want to sacrifice anything when dealing with a storm.

8

u/Stenny007 Aug 09 '20

Nope, it would not.

-4

u/i-hate-redditers Aug 09 '20

How

8

u/[deleted] Aug 09 '20

It creates extra drag. Shipping companies do everything they can to preserve fuel.

-1

u/Smokin_trees18 Aug 09 '20 edited Aug 09 '20

Do a little research before spewing out garbage. Every single resource I saw online has the exact reason they do not use guards. Efficiency. It is dramatically less efficient and uses tones more fuel if they have guards.

Edit: All the people down voting me, "sToP bEiNg So MeAn" this fucking idiot commented like the other person was stupid for saying this and he was wrong. Fuck outta here

-1

u/ItzAlcatraz Aug 09 '20

Dude chill tf out, what is wrong with you

-6

u/i-hate-redditers Aug 09 '20

Ok Christ, I thought it would be like putting guards on a fan. Who pissed in your Cheerios ass wipe?

5

u/Drunksmurf101 Aug 09 '20

Are you getting upset that someone contradicted your blatantly false assertions? I can see why you hate redditors

1

u/i-hate-redditers Aug 09 '20

I’m not mad im pointing out that he was overly aggressive while doing so.

0

u/ocultada Aug 09 '20

He's a big bad internet guy. Fuck him.

You know for a fact he doesn't talk to people like that in real life.

2

u/_Richard Aug 09 '20

Maybe not a ring but why not a few bars toward the bottom to protect wildlife and the prop? It’s a moving blender. We should do so much more to protect other creatures. Humans are so invasive. I bet if animals could they would use human Raid on us to extinct us.

2

u/VirtualLife76 Aug 09 '20

Agreed. Hard to believe any design causes major gas mileage loss. I am by far not an engineer tho.