Miss Budweiser Hydroplane Help Needed

[Monkey Wrench]

OK, so I bought this Miss Budweiser hydroplane boat from this goober named NCNitro. Ran it a bit last summer and decided to get it out the other day for a twirl on the pond. Problem is (and this has nothing to do with NCNitro, just bustin's his chops a bit) that the prop doesn't seem to have any "bite" in the water. Prop spins and the boat moves, but even at WOT, it barely moves.

This thing moved liked a raped ape in the water last year and I'm a novice to boats, so I'm at a loss as to why this is happening.

Checked the connections of the prop to the shaft and the shaft to the engine and all seems good and tight, so I don't think anything is slipping (although I almost wish I had a clutch, so it could idle without spinning the prop).

So, any ideas, wet-heads? Any help appreciated!

 

[Rolex]

Have you changed anything at all that would affect the balance? It sounds like cavitation.
Start out real slow, and very slowly gain speed, and see if it responds to that.
It could either be the trim tabs or the pitch of the prop.

 

[Monkey Wrench]

Have you changed anything at all that would affect the balance? It sounds like cavitation.
Start out real slow, and very slowly gain speed, and see if it responds to that.
It could either be the trim tabs or the pitch of the prop.

No, at least not on purpose. The only thing I've done is change the prop because the one I had on it last year cracked.

 

[Rolex]

Did you change anything about the prop, or did you replace it with an exact replacement part?

When it's in the water, and you keep it from moving forward, are you getting a lot of action from the prop? Water or air movement?

 

[NCNitro]

See what happens when you give a Monkey a boat! You broke my damn boat man!

 

[Rolex]

Hey, Monkey! It's Goober!

 

[robmob]

"Cavitation"

I learned a new word today.

 

[Monkey Wrench]

OK,

1. NCNitro: I didn't break your damn boat, I broke MY damn boat! Therefore, you have now taken on the coveted title of "Uber-Dink" from Beason. Thanks for playing.....here's your sign!

2. Robmob: I'm so glad you expanded your vocabulary by one word today. Now, use it in a sentence. :

3. Rolex (who surprisingly is being helpful): I haven't really checked to see how much air it's moving and when it's in the water it "seems" to move a good bit of water, but I don't feel much pull from the boat itself. I am fairly certain it's an exact replacement, though. Is it possible to have a prop mounted backwards? Just now thought of that possibility.

 

[Rolex]

Yes it is. If you cup your hand, the prop blades will look like that. The cupped palm should be to the outside/rear of the boat.
If you didn't notice that when you mounted the prop, you move up a step to take the Uber-dink position.


Today's lesson. Pay attention to this and take notes. It WILL be on the test.

Inertial Cavitation:
Inertial cavitation is the collapse of a spherical void within a liquid. When a volume of liquid is subjected to a sufficiently low pressure, it may rupture and form a cavity. This phenomenon is termed cavitation inception and may occur behind the blade of a rapidly rotating propeller or on any surface vibrating underwater with sufficient amplitude and acceleration.

 

[Monkey Wrench]

I'll flip the prop and see what happens. Thanks Rolex, I appreciate the help!

Joe, you're still a goober!

 

[Rolex]

So, can I assume you looked at it and you know it's backwards?
The cup effect of each blade is obvious. When the prop is rotated in the right direction, it slices the water and shoves it off the trailing edge.

Basically it works like a wood screw. It starts off with a shallow leading edge, and gets more aggressive at the trailing edge. You CAN'T mount it backwards unless you're a complete dork. : )

 

[Monkey Wrench]

So, can I assume you looked at it and you know it's backwards?
The cup effect of each blade is obvious. When the prop is rotated in the right direction, it slices the water and shoves it off the trailing edge.

No, not yet. Don't need a fresh beer yet! :

I'll take a look when I go back to the basement, but I think, based on your sage advice, that may be the problem.

 

[Monkey Wrench]

Well, the prop is mounted as per your diagram, DORK, so now what have you got for me?

 

[Rolex]

In case you're not sure of nautical terms, aft means rear.
Note the graduating width and pitch of each blade as it shoves the water aft. On your next trip to the basement, take a picture for me.

 

[Monkey Wrench]

In case you're not sure of nautical terms, aft means rear.
Note the graduating width and pitch of each blade as it shoves the water aft. On your next trip to the basement, take a picture for me.

Eye, eye, Captain! Will do!

 

[robmob]

Isn't this cavitation?

 

[Rolex]

Eye, eye, Captain! Will do!

That's "Aye, aye", NOT eye, eye. Eye, eye is what a pirate would scream before being issued his patch.

Again, note on the diagram 'AFT', and visualize this prop turning in a clockwise direction as you see it here.

Isn't this cavitation?

LMFAO....I think so, and that would explain Monkey's problem.

 

[NCNitro]

Isn't this cavitation?

No, that is actually "Rectal Cranial Inversion" It is definitely what the Monkey suffers from.

 

[Rolex]

On several occasions I've had "Rectal Glaucoma".
On days that I've gotten it, I just couldn't see my ass going in to work.

 

[Monkey Wrench]

OK, here are some pictures. Not the best quality, but I hope they are good enough.