Been boating for years good explanation

Thank you for this. I’ve found myself confused trying to understand this concept. Makes perfect sense now!

Changing out my water pump and noticed it was ripped apart. Didn't know why till stumbled across this video. My propeller has all kinds of nicks and wear and tear all over it. Now I know why ! Thanks for the video !

Great video and explanation mate! Thank you for the taking your time to explain it!

Very well explained.

very well explained by you and understood well on this end because your explanation of a complicated physics situation was applied and demonstrated on the prop with your fingers on the edges. I've heard this explained a 1000 times by very well informed and knowledgeable people, your explanation visual demonstration best by far. thank you.

You taught me something new, ole timer! Thanks for the video

Wow man thank you, super informative

Yep. It helped. Thanks!

Great explanation. Thank you!

Best video on KZfaq!

Much Thanks 🙏🏼 from down under 🦘 for your Considerate Sharing. My late På used to say that if yà don’t learn something per day, it was just a waste. I bought a trailer boat recently kitted for moderate seas 🌊 & your info’ builds muy Confidence 🖖🏼🍻😃 Be Well, YåLL🙏🏼

Thank you. Best explanation I found.

Great explanation! Thanks!

really enjoyed the information thanks for sharing

I like people like that smart and simple and knowable not too many people left like that

Great job. I am a newbie and you explained this very well

Good Stuff...Thanks

You're the man!

Great explanation.

Outstanding explanation

Good explanation...its something boaters need to know.

ty om finally i understand

Lovely video,,thanks to you sir

Hey hey Jeff your the Chieff. Pretty good doh clear and slowly, way to go

You have cavitation a little backwards. The vapor bubbles are formed at the leading edge of the blade and collapse at the trailing edge. Cavitation happens when there is a lack of net positive suction head NPSH. In the case of a propeller, NPSH is obtained by the speed of the water, towards the leading edge of the blades. This is why high pitched props, cause cavitation during hard acceleration. Once the boat is up to speed, the cavitation goes away.

Thanks for the great video! How will I know if my engine is mounted too high? What are the clear signs that the propeller is getting air, even a little bit?

that bottom end has seen some rockatation lol

Thank you

You’re a smart man!

Thanks for that wisdom, that is why stainless prop are better yeah?

Hi there, I am new to boating, I have a concern about my boat I still couldn't figured out. I bought it used the engine is 5.0 Murcruiser I/O with 220HP. It's not getting the speed. Once I watched your video I learned about cavitation. Do you think this is the problem I am having too. I know my prop is pretty bad shape. What would you recommen for me. Thanks Sam

Interesting information. Great description! I have a 40 horse force motor. Short shaft. When I am at full throttle, I get what seems like occasional Misses. I do have some slightly chewed up edges on my prop. Do I have a carburetor issue or might those Misses be cavitation?

Thanks for that description, also that is a very worn looking outboard leg!

What pitch prop are you running? I have tried running a 14 on my 30 evinrude and it ventilates on take off and if I'm following behind another boat where the water is aerated. Do you think moving up to a 15 pitch would help

Thank you for the info. I just put a “prop guard” on my 200hp Yamaha. At slow speed its fine but over 20 mph it starts listing the boat hard (23footer). At about 25 mph I thought it was going to completely roll over. Any idea what is happening and how to correct it?

hello i m from croatia.. i have old johnson 60 on a smal plastic 4.20 meters boat. the motor is put in corect hight but the problem is when i go from standing still to full trotle boat instantly jumps in plain but then goes in high rpm like it sucked air or the prop is sliping. but when i go easy on trotle lets say 10% every 5 sec i can get to 100% trotle without any problem and at 100% max rpm is 5600... realy dont know what 2 do. prop is 11 3/4x17 aluminium and i m mising CONVERGING RING on it. is it posible that its sucking exaust in and velntilating? tywm for any information :) ps. sory for my english

Can boats with a lot of seagrass grown on it experience ventilation? It feels like mine is spinning in air on top speed because it goes much slower than before it was so grown under the boat.

great video thank you. could you please tell me if hydrofoil would be beneficial for my 6hp 4stroke outboard? its on a 10ft inflatable dinghy. some say hydrofoils are only good for 10+ hp outboads anything smaller is a waste of money and will slow down the boat.

Seiko SKX007. I've had the same watch for 15+ years.

HI MAYBE YOU CAN GIVE ME SOME SUGGESTIONS ON AN ISSUE IM HAVING. I HAVE A JOHNSON 30HP AN I HAD TO MAKE A HARD TURN AN I GUESS THE MOTOR VENTILATED, BUT NOW WONT START. WHEN TRYING TO START IT, IT SEEMS TO BACKFIRE FOR LIKE 3 SECONDS THEN CUTS OUT.

so why does surface propping work so well then isn't that a ventilated situation? I surface prop sometimes with the prop half-submerged and go faster...

I have one of this dory! I just purchase a brand new Yamaha f25 tiller motor. The dealer wanted it to charge me 300 dollars to install the motor, but I was painting the bottom and doing some modifications on the inside. I went by what the manual and the Yamaha dealer recommended on how to install it. They required that the cavitation plate is level with the bottom of the transom. So I did and when I took the boat out for the first time with my brother in law going out and being out there was perfect until we started heading back in we noticed the motor propeller slipping my brother in law said its sounds like it’s cavitating. I have a 20” transom with a 20” long shaft. I thought maybe it was because my brother in law is a heavy guy and he was standing right in the front of the bow. so when we hit any small wave the propeller was coming out of the water. He said it shouldn’t do that. I email the Yamaha owner and send them pictures of my installation and he said he was going to pass the pictures to his worker guy. It’s been a week haven’t heard anything. I want them to reinstall it to see if it would solve the problem. When I took the boat yesterday out for a ride myself to see how it rides with one person it was a horrible ride if I tried to go fast at all. The bow would stick really high and any little wave felt like you hit a rock and it was scary. I just want to sell this boat and motor if I can’t fix it. 🙁

Atmetferic pressure is around 15 psi, water boils at 100 degrees, when you apply a absolute vacuum lowers Atmetferic pressure water will boil at aroind 20 degrees.

Great explanation...although no water is turning to steam. It's just pockets of air or a difference in high and low pressure creating an absence of water. Still...thank you.

Lookin at the lower unit of this outboard....He's still got a lot to learn! It's beat to #hit! Maybe he should learn how to take care of his outboard....

How does surface drive work

That prop has seen some sand. Mine looks the same

40-50,000 Dollar prop ! OMG!

Thank you for this good explanation. Why can't USA hurry up and change to the metric system :)

The majority of the bubbles is exhaust.

Simply, ventilation is sucking in air, cavitation is boiling water.

We are creating a 'kayak' site for marine/boating parts and accessories to help people find the best deal vs. having to go to lots of individual stores to research - we may also provide links to content on youtube such as yours so people can also get advice. What do you think about this idea? Do you think it is a good idea for yourself/your audience? We would like to get some feedback before we get too far down the road. If you do like it, is it the kind of site that you would feel comfortable advising your audience to check out? Thanks! Cheers, Steven

You can feel the difference

What will cure burp cavitation. I can go at full throttle then you will hear a burp and the boat hesitates slightly. This only happens at top speed. 4.3 l8tr with alpa one drive 200 up hydrofoil did not help.

Cavitation is pockets of vacuum causing implosions, not pockets of steam causing explosions. Aeration is when there is air in the hydraulic system, basically what a prop submerged in water is, that compresses and the energy is lost through the compression of air.

At sea level atmospheric pressure is 14.7 lbs/sq.in

Your prop shouldn't be spinning while you're putting it on the trailer.