prop shrouds

[waterwar]

until we meet again

I will visit again soon and reply to ones that are on subject.
Personal comments will no longer elicit any response

*People who do such are irreproachable and a waste of time, and merely post to see their own name in print!



Vows made in stormy waters are forgotten in calm ones.

 

[waterwar]

I apologize

You should have said that some pages earlier IMHO

Sorry i have Fios internet optic cable and it is unreliable in this location...
seems the ants attack the casing underground here..

I have to go on and off at the ant's will sorry and i do work outside its 65 degrees here today

 

[waterwar]

the subject was dismissed when the old thread was reviewed i apologize for any antagonism
or misconceptions sometimes you have to jump start when you go hit or miss on computer connection my fault

 

[gonzo]

My experience with nozzles is in fishing trawlers and offshore tugs. They have a definite advantage to about 7Kt which declines at different rates depending on design.
Waterwar: if you don't want personal comments, you should abstain from making them. Also, what level of engineering and math do you understand? You are asking for scientific data.

 

[waterwar]

thank you

I have a college degree and took calculus
i appreciate your sincere response

 

[waterwar]

If you note in the test link i sent Mr Shulltz claims a boost that overcomes the drag is this possible he claims a speed boost at high speed

 

[waterwar]

Everything I have been able to fathom indicates that all prop guards will invariably reduce speed

this is only one that has 'test ' to prove it fake or what

 

[gonzo]

That has been around for a while. I have never seen any independent data substantiating it.

 

[Jeremy Harris]

If you note in the test link i sent Mr Shulltz claims a boost that overcomes the drag is this possible he claims a speed boost at high speed

At low speeds thrust will be increased, but this can't overcome the increased drag from the duct at higher speeds.

Some of the advertising for these add-on ducts for outboards is a bit misleading, as they tend to compare static thrust, sometimes described as bollard pull.

Ducts work well at increasing low speed thrust, and can improve the ability of something like a ski boat to lug inexperienced skiers out of the hole, but as soon as the boat gets above a few knots, performance will fall off when compared to an open prop.

Jeremy

 

[waterwar]

Thank you My boat can get a skier up its a 40hp old as dirt 1957 OMC
so I could not do pull if i
I put on a prop guard?

 

[waterwar]

In other words the test that was performed is weighted by mr. shultz. I notice a very large engine was used.

 

[gonzo]

What does "so I could not do pull if i
I put on a prop guard?" mean?

 

[waterwar]

He claims an actual increase at high speed

 

[waterwar]

It means that at present I can pull a skier in my ole crate of a boat..
What I am asking is if I put this prop guard device on will it cause a loss of speed so I am unable to tow a skier?

 

[gonzo]

If you have a propeller and nozzle properly manufactured and matched, the "hole shot" will be better. Your top speed will be less. There is no generic answer, it depends on the set up.