Torque or Horsepower?

[GlastronGuy]

Who said?:
"Cubic inches make torque, and torque is what makes the jetboat run."

[Cas]

got bored scratching yourself I see............

[MudPumper]

Didn't I read that in the new ***boat somewhere???

[GlastronGuy]

Originally posted by Cas
got bored scratching yourself I see............

[LVjetboy]

Somebody who didn't know what they were talking about.
jer

[MudPumper]

Originally posted by LVjetboy
Somebody who didn't know what they were talking about.
jer
I'm not claiming to know shit about it but I think Greg Shoemaker does!!!!!!

[Cas]

actually, Pops1 touched on the reason why Greg and many others are correct in one of his most recent posts in the "Is your bowl hydraulically correct" thread. The real answer is.....both
here's what he wrote:
If you are starting to stuff your bowl too early pressure builds, cutting down the output of the impeller. Remember this some very high percentage of your motion comes from frontal pull by the impeller. I have never been able to find the Math Man that can tie this down for me. I think the % is upper 90s- On a prop its cup pitch and size determines the forward motion per rev. less slippage of 10-20%
On a Jet you have no slippage as the water is incapsulated Yet we have volumn, pitch & thrust. I am overplaying the story to get your mind to a thinking point of forward pull vs all pressure thrust. Under this scenario Torque and HP play the strong power to the future of Jets- It just keeps getting better!

[MudPumper]

The whole pull thing has always intrigued me. If you have ever looked at the nozzel on a jet from inside the boat while it is moving with a diverter up you will see that the pump is completely out of the water and shooting the water into the air. So there can be very little thrust. It must all be pull.

[JEThro]

Thrust is important if your getting some "tang". Pull is what you do when your not.

[cruser]

Here we go again. Thrust is the result of accelerating mass in a specific direction. It has nothing to do with the environment around the mass. There does not have to be something to push against. It is all about the "for every action there is an equal and opposite reaction" law. This was described a long time ago and is still true today. If this were not true, rocket ships in space would not accelerate because they have nothing to push against.
As an experiment, go out to your patio or any other hard surface and stand on roller-skates or something else that rolls easily. Using your garden hose with an adjustable nozzle on it, squirt water straight out from your body. If the hose pressure is high enough and you are squirting using the most concentrated stream setting, you will start to move backward. Try squirting the side of the house or any other solid object. You won't accelerate any faster because the water is "pushing" on that surface. If you adjust the nozzle until you have a less concentrated stream, you won't move as fast, if at all. This is because the water is pushing in many different directions at the same time, each direction canceling out the opposites ones resulting in little or no thrust. Also the water is accelerated less when not as tightly concentrated when using the other settings. Essentially the same volume of water is coming out on both settings, pushing against the same air, the only things substantially different is the speed and unified direction the water exits the nozzle, thus producing thrust.
The main reason for moving the pump out of the water is to reduce drag.
cruzer