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Just Me
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Discussion Starter #1
Since the jetaway doesn't fit my Jacuzzi pump, my next question is at what speed do you need a jetaway to be safe? The sleekcraft is a shallow V and it runs a Jacuzzi WJ pump with a Jacuzzi B impeller. I've been told this would equate to a Berkly A impeller. With between 550 to 650 HP and a motor that will turn 6500 easily will I be reaching speeds where if i let off the motor quickly or have something break a jetaway will be needed?
 

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Since the jetaway doesn't fit my Jacuzzi pump, my next question is at what speed do you need a jetaway to be safe? The sleekcraft is a shallow V and it runs a Jacuzzi WJ pump with a Jacuzzi B impeller. I've been told this would equate to a Berkly A impeller. With between 550 to 650 HP and a motor that will turn 6500 easily will I be reaching speeds where if i let off the motor quickly or have something break a jetaway will be needed?
with around 600hp you will be fine without the jetaway, unless you do a lot of running on the trailer. save your money. realistically a jet a way is nice feature to run the boat on the trailer.
 

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Nobody has ever said it is needed, unless you race. It works and has definite advantages. Lose a motor at 70 plus mph and then wish you had one. What price is safety and piece of mind:)hand Plus, the advantage of running on the trailer:)devil
 

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jetboataholic
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2,798 Posts
Nobody has ever said it is needed, unless you race. It works and has definite advantages. Lose a motor at 70 plus mph and then wish you had one. What price is safety and piece of mind:)hand Plus, the advantage of running on the trailer:)devil
I would love to have one for that very reason, but I don't have that kind of money to throw around.:(
 

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Resident Ford Nut
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10,079 Posts
As far as the saftey aspect goes, it all depends on your boat. I can side-step the throttle in the CP at 90+ and the boat just sits down nice and easy. The engine produces North of 800hp. The engine power isn't as much of an issue as to how the boat behaves on shut down. Just my .02

Sleeper CP :D
 

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jet away

Each boat is different. My 21' Daytona has two long straight sponsons that help it shut down straight. Any type of V hull that would tend to set down one side first would be a bigger risk.

If your looking for the best safety devise, use a pop-off valve. Better in relieving pressure than the jetaway. some use both.

Jerry
 

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Just Me
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4,061 Posts
Discussion Starter #8
Each boat is different. My 21' Daytona has two long straight sponsons that help it shut down straight. Any type of V hull that would tend to set down one side first would be a bigger risk.

If your looking for the best safety devise, use a pop-off valve. Better in relieving pressure than the jetaway. some use both.

Jerry
Since i'd either have to buy a jetaway and have it remachined for the Jacuzzi or add the energizer kit first, I'll look into just adding a popoff valve when the boat starts reaching more speed. I think I'll also take it out and start making some passes starting from slower to faster, then lift and see how it handles.
 

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Since i'd either have to buy a jetaway and have it remachined for the Jacuzzi or add the energizer kit first, I'll look into just adding a popoff valve when the boat starts reaching more speed. I think I'll also take it out and start making some passes starting from slower to faster, then lift and see how it handles.
the popoff is not a bolt on deal, you must machine the hand hole on the suction housing.
 

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Glendale Arizona
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2,368 Posts
Total agreement with the following statement. Spend you hard earned bucks on something else. I doubt that you would need either a popoff or jetaway unless you're running a ton of shoe, or a real aggressive loader, or both. There are guys on here running between 90 and 100 mph with semi-v's and no jetaway or popoff.

with around 600hp you will be fine without the jetaway, unless you do a lot of running on the trailer. save your money. realistically a jet a way is nice feature to run the boat on the trailer.
 

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"That Guy"
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418 Posts
I have some some questions, I have a 18ft tunnel (jet) with all the crap that that is in the last post. it shut down @ MPH and hooked pretty bad. I'm not i don't have the $ to pit a jet away, so whats a pop-off? and whats involved in installing it and what kind of money are we talk'n?
lastly, whats wrong with running the boat on the trailer for 5 or 6 min?
does it do something real bad?
thanks ...:|err
 

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Just Me
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4,061 Posts
Discussion Starter #13
Make a hard pass and let off the throttle. If the shut down is sketchy you might want one. How about some specs on your ride?
It's just an ol 19' 77 sleekcraft (definately nothing to look at). I bought it to just throw it on the water with minimum fuss, but due to the floods and not being able to get it on the water, the mod bug bit me. The heads are now at the machine shop to be ported and refreshened up. There is a tunnel ram heading this way. And if my machinest mentions it just one more time, there will be a stroker kit going in the bottom of the 440 in it. Man these floods get expensive when you have a boat sitting around not being used. I can tell this one will turn out like some of my cars. Nothing to look at, but it will run the way I want to when I'm done with it. And maybe it will get wet yet this year. I hear they boat as late as NYD out west. :|err
 

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Running your jet dry is hard on the impellar/wear ring. If the hose is on it's better but still not as good as being submerged.
 

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All depends on the boat. I was running 800 hp in a v bottom with an MPD Jacuzzi with zero need for the popoff or jetaway. Play with your boat and understand how it will react to getting out of the throttle. Im not certain, but I dont think you want to throw too much power at a tahiti...
 

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on 3 go.....
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846 Posts
TRUE Safety Products

The way it was explained to me:

The pop-off is the only "true" safety release. Jetaways will allow for water to be released, but not nearly as much as the pop-off.
I have seen jetaways help during a motor failure and they're fantastic for running your boat on the trailer, but don't consider it a true "safety" product.

Just my .02 and be safe!
 

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The Jet-Away Is a 'True' Safety Item. The unit is a clutch system which functions every time one takes their foot off the accerarator. The clutches allow dissipation of motor Tq (clockwise rotation) from impeller drag (counter-clockwise force due to lack of power being put to the impeller and water coming onto its vanes). In extreme cases as when the motor freezes, the clutch system disengages the motor from the pump. It is only a Secondary, though designed in, feature that the device allows the motor to be run on the trailer without turning the pump.

Any of the 'PopOff's' are 'True' Safety Items. Their function is to divert a major portion of the incoming water out of the pump before it reaches the impeller and goes thru it creating forward thrust. Something that a number of people have not thought of is that in a 'Blow Over' situation, setting the PopOff off too late (while water is still coming into the intake) can actually add to the blow over as the down force exerted by the water going out the throat of the PopOff, at the angle it typically does, can add to the rotational force involved in the blow over event.

Both Devices are Safety Devices, nothing more, nothing less.
 

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WELL I CAN TELL ALL OF YOU IT DOES NOT WORK EVERYTIME CAUSE IVE BEEN WET......... ( jet away ) but it does work sometimes....:)hand only true safety device is to keep it on the trailer :)hand
 

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Ivan hows the boat coming along?
Making slow progress even though economy has hit a couple of sponsors to where money is tight to say the least. Have uncovered a few aero/hydrodynamic things we need to sort out before proceeding with the hull. All in all, good given everything that's afoot these days. Thanks for asking.
 
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