I have this irrational fear of swimming close to boat propellers. Ever since I watched the movie finding Nemo when I was young, seeing his dad nearly being torn up by the propellor. It gave me shivers.
Yes there is cavitation and it is not what is coming out of the rear which is exhaust but around the blade, this is inherent to the quality of this blade
Theres a small cavitation on the prop flukes at full speed but its normal for the type of prop and the angle of the flukes and the stream you see shooting out from the middle of the prop is the exhaust , not heavy cavitation
The exhaust gasses come out of the back of the engine hood (above water) while idling, only when an outboard throttles up in gear they gasses come out of the propeller. The bubbles at the end of the blades is a light form of cavitation. Water boiling because of the low pressure. Think its an aluminium prop as it occurs quite soon. A stainless prop has better performance.
And this is why a sportfish vessel will out fish every outboard. Harmonic and no exhaust trail make it extremely clear for your baits behind boat look deadly
This is meaningless. The hydrodynamics of an engine/propeller pair running while being held stationary, is NOTHING like the flow while it is moving. The flow of water past a prop in motion does not behave this way. What you are showing is a 100% slip situation. In actual use, a prop only slips a small percentage. What happens behind it in those two conditions is way different.
hello, it look great. i need a little help about the selection of motor with regards the weight of the ROV , example, if you move a 20 kg ROV at speed of 4 knot in salt water , then how you select the motor, how much thrust you required to move with constant speed? if you have any material or formula, please help me into this.
that was ventilation as the boats not moving but the water is it sucked air from above the anti-ventilation plate and then held it. you should come off the throttle then back on it again.
Outboard engines have their exhaust through the propeller. Cavitation happens on the front side of the leading edge and on the tip of the propeller due to suction and vortex.
I have Submechanophobia and this doesn’t trigger me an awful lot but I wouldn’t swim next to even a prop this small Edit: Submechanophobia is we’re you have a fear of something large submerged under water, for me propellers, large underwater structure and anchors are the worst.
The bubbles comminf from the center of the prop are an exhaust trail. The bubbles forming at the edges of the prop are cavitation. When water pressure decreases, so does the boiling point of water. The back side of the prop creates a low pressure when quickly displacing water. This low pressure causes the water to "boil" and that is what causes the bubbles.
This is NOT CAVITATION!!! People should know what they are talking about before spewing ignorant comments on YT !! A outboard engine exhaust comes out the center of the prop, that’s exhaust not cavitation!!
If you ever fired up an outboard engine outside the water (to wash the cooling system with fresh water), you would notice that, in fact, the exhaust is at the center of the propeller. That is not all cavitation. Cavitation bubbles would appear mostly at the blades, not at the center. The blades are engineered to keep caviatation to a bare minimum. Since the engine is being accelerated, the amount of air passing the combustion is so large it makes that bubble tail.
Youssif Galal either you don’t have an outboard or you have some weird model with an odd exhaust system. Nearly all outboards have the main exhaust coming from the center of the prop. When it’s in neutral there is minimal exhaust coming from that vent. There was some cavitation on this blade but the main source of the turbulence is from exhaust.
Per quello purtroppo il bastone della Gopro non può essere d'aiuto, sto pensando di immergerla in un fondale di circa 1,5 metri, e navigare sopra la camera che poi dovrei recuperare, purtroppo lavorando in estate non ho il tempo di fare tutto quello che vorrei.
@@leemilica Little ones don't bother me. It's the huge propellers underwater that do. And it's not because I'm a crybaby. I watch and play horror games and movies daily XD
That is ventilation, not cavitation. Cavitation is when the propeller pulls air to it from the surface. That is why an anti-cavitation plate is positioned between the waterline and the propeller. Ventilation comes from drilling holes in the exhaust ports of the prop to let exhaust out at the fins of the propeller, thus causing less drag which allows the engine to spin a bit easier. It helps the boat get on a plane faster.
Wrong. When water pressure decreases, so does the boiling point of water. The back side of the prop creates a low pressure when quickly displacing water. This low pressure causes the water to "boil" and THAT is where the air comes from. This is cavitation.
I have this irrational fear of swimming close to boat propellers. Ever since I watched the movie finding Nemo when I was young, seeing his dad nearly being torn up by the propellor. It gave me shivers.
Buy a stick for the gopro and fear will disappear! Voila!
Submechaniphobia. Look it up man
@@tornadotayte Yup, I definitely have this. This video gave me the creeps
Okay, now I know what my newest nightmare's gonna be -- getting stuck too close to a boat propeller going at full blast.
Thanks for that. 👍
ruclips.net/video/UYrSXmkO6Nk/видео.html
Yes there is cavitation and it is not what is coming out of the rear which is exhaust but around the blade, this is inherent to the quality of this blade
It looks like an aluminium prop, so it is what it is.
Thank you very much for the opportunity to see the cavitation underwater. Brilliant video.
The last test look really safe!
They have a fetish with getting their fingers chopped off
Or thet use a pole for the GoPro.
calm your tits. just because a camera is near something doesnt mean a person is near it
@@dirtrider88 haha calm your tits ohh that's hilarious
@@lucavanzi can you get a joke?
Theres a small cavitation on the prop flukes at full speed but its normal for the type of prop and the angle of the flukes and the stream you see shooting out from the middle of the prop is the exhaust , not heavy cavitation
how can we minimize cavitation by changing its design?
By making greater propeller wings, maybe use different angles for different speeds and cooling the prop
I'm watching this because it looks like a fan.
Im watching this because it looks fan.
Funny how you can't see exhaust coming out when the engine is idling.
I expected to see bubbles even then.
Probably has exhaust ports on the leg like my evinrude
Wait the exhaust comes out the propellers
@@allgaming4045 Well, the hub.
@@allgaming4045 It's called through hub exhaust. Most common thing on outboards.
The exhaust gasses come out of the back of the engine hood (above water) while idling, only when an outboard throttles up in gear they gasses come out of the propeller. The bubbles at the end of the blades is a light form of cavitation. Water boiling because of the low pressure. Think its an aluminium prop as it occurs quite soon. A stainless prop has better performance.
And this is why a sportfish vessel will out fish every outboard.
Harmonic and no exhaust trail make it extremely clear for your baits behind boat look deadly
Cavitation happens with all props, its high engine torque or rpm that causes it. Slow rpm after holeshot cavitation will stop.
This is meaningless. The hydrodynamics of an engine/propeller pair running while being held stationary, is NOTHING like the flow while it is moving. The flow of water past a prop in motion does not behave this way. What you are showing is a 100% slip situation. In actual use, a prop only slips a small percentage. What happens behind it in those two conditions is way different.
I was about to say the same thing but you beat me to it 😂
I dunno about marine propeller engines but
In aircraft engines there are two types of thrusts commonly referred, installed and uninstalled thrust.
Bro shut up enjoy the video
Who cares about hydrodynamics here?
I think it was cool to watch.
Still looks cool
Is that a yamaha 60 outboard as i have one and it looks identical
I love that little whirlpool at the top
Cool! It looks strong.
"Conn, sonar sierra 1 is cavitating"
A fellow cold waters player? I see you're a man of culture as well
Surprisingly quiet. I thought it got louder when your further away due to that buzzing sound
it's cavitating , it can damage the shaft due to vibrations
Nicely done
very interesting
hello,
it look great. i need a little help about the selection of motor with regards the weight of the ROV , example, if you move a 20 kg ROV at speed of
4 knot in salt water , then how you select the motor, how much thrust you required to move with constant speed? if you have any material or formula, please help me into this.
Did u get ur answer?? If so, plz tell.. I too have the same doubt
That last part took the breath outta me.. I thought he was gonna get pulled in from the side!
Is there ment y to be a water jet in the middle of propeller
that was a great video of a propeller I wish I could see one in real life !
I can tell you I own an out drive but would never go down there to see it
I hope you never see one by falling out of a boat and being sucked onto it
thanks.
maybe putting a cage around the fan, block fish from getting slashed by propeller
But also fuck up the water dynamics of it
Have you grown up?
When the fuck has anyone chopped up a stupid fish with it
@@James-xc9zy LOL. He could've at least said manatee lol. Fish swim out the way long before boats get to them
Then the fish will just be fish food...
@@James-xc9zy alot of people have asshole
@@rev9fan1 fish are friends not food
What’s the air that are coming out?
Thank you sir, knowledge is power 👍
I wonder Where did the air bubbles come from underwater ?
The water is actually boiling. High pressure causes this.
Or maybe it’s lower pressure. Forget which one.
Why the engine is so small??
I know it's a tiny propeller but this still scares me
I don't even own a boat nor have I ever even been on a boat, why am I watching this
It's called curiosity. Till now you have good curiosity though. I hope you never have bad.
Why has the inlet been blocked off?
WOW COOL!!!!!
That is cool
Mooring is OK!? Hello from Saint -Petersburg Russia! Chmoki!
It was one of my first videos with gopro. Next time I'gonna shoot in 720/240 fps and then slow down even more.
The best
is this terrifying to anyone else
No
@@TateH25-o7v 😔
im tired.
And this test proves ? Throw a hydrofoil on it and compare . (Something) lol
It proves nothing. But you can determine how bad your prop cavitates.
that was ventilation as the boats not moving but the water is it sucked air from above the anti-ventilation plate and then held it. you should come off the throttle then back on it again.
It is the water behind the propeller boiling due to low pressure, not air. This is cavitation.
Outboard engines have their exhaust through the propeller. Cavitation happens on the front side of the leading edge and on the tip of the propeller due to suction and vortex.
I have Submechanophobia and this doesn’t trigger me an awful lot but I wouldn’t swim next to even a prop this small
Edit: Submechanophobia is we’re you have a fear of something large submerged under water, for me propellers, large underwater structure and anchors are the worst.
I googled this and clicked images... Yeah fuck that.
what happens when a person comes in?
He dies
They die
can someone explain to me the bubbles
The bubbles comminf from the center of the prop are an exhaust trail. The bubbles forming at the edges of the prop are cavitation. When water pressure decreases, so does the boiling point of water. The back side of the prop creates a low pressure when quickly displacing water. This low pressure causes the water to "boil" and that is what causes the bubbles.
What type of engine is that?
Mohdaliffhassan Hassan thats a yamaha , probably a F50 or F60
Yamaha
thank you for sharing!
This is NOT CAVITATION!!! People should know what they are talking about before spewing ignorant comments on YT !! A outboard engine exhaust comes out the center of the prop, that’s exhaust not cavitation!!
dude your so wrong. Exhaust comes from above, when engine is idle there are no bubbles coming out. Its cavitation
Still have one blade cavitating as well
you can literally see cavitation coming from the blades,
What the f*** is wrong with you?
If you ever fired up an outboard engine outside the water (to wash the cooling system with fresh water), you would notice that, in fact, the exhaust is at the center of the propeller. That is not all cavitation. Cavitation bubbles would appear mostly at the blades, not at the center. The blades are engineered to keep caviatation to a bare minimum. Since the engine is being accelerated, the amount of air passing the combustion is so large it makes that bubble tail.
Youssif Galal either you don’t have an outboard or you have some weird model with an odd exhaust system. Nearly all outboards have the main exhaust coming from the center of the prop. When it’s in neutral there is minimal exhaust coming from that vent. There was some cavitation on this blade but the main source of the turbulence is from exhaust.
Video molto interessante🔝, sarebbe bello poter vedere questo effetto con barca in movimento...
Per quello purtroppo il bastone della Gopro non può essere d'aiuto, sto pensando di immergerla in un fondale di circa 1,5 metri, e navigare sopra la camera che poi dovrei recuperare, purtroppo lavorando in estate non ho il tempo di fare tutto quello che vorrei.
палец не пробовал засунуть?
This is how to create oxygen under water.So that you breathing like a fish.
Submechanophobia
[ Agressia ] if you are a crybaby. How can this little propeller scare you?
@@leemilica
Little ones don't bother me. It's the huge propellers underwater that do. And it's not because I'm a crybaby. I watch and play horror games and movies daily XD
@@deadanimasher678 underwear?
@@deadanimasher678 just like me
@@deadanimasher678 Same here :(
Why not upload in 1080P 60fps?
Which motor used for this?
Yamaha 60 outboard
0:28 udaranya muncul dari mana ya?
That's the exhaust
Yamaha
I needed to know what one looked like because I was drawing one !
That is ventilation, not cavitation. Cavitation is when the propeller pulls air to it from the surface. That is why an anti-cavitation plate is positioned between the waterline and the propeller. Ventilation comes from drilling holes in the exhaust ports of the prop to let exhaust out at the fins of the propeller, thus causing less drag which allows the engine to spin a bit easier. It helps the boat get on a plane faster.
Wrong. When water pressure decreases, so does the boiling point of water. The back side of the prop creates a low pressure when quickly displacing water. This low pressure causes the water to "boil" and THAT is where the air comes from. This is cavitation.
@ 5:15 ...
PRO PLAYER BROO IN GAME HAHAH😂😂😂
That's a lot of Cavitation
Not neccesarily .
Subnautica?
why do you think this is not cavitation ?
A little bit of both of you know what I mean
Hardcore Gaming exhaust
lot of cavitation
Thats mostly because its standing still
Biker
Toy ship
cavitation from hell
no catalytic converter no nothing. Just dump the exaust into the ocean. disgusting and disgraceful!