silly question

C

csmall06

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How does a jet boat, such as the yamaha 230 series back up. How does the jet work when you shift in reverse?
 
M

MarkHPCA

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Jun 2, 2004
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Re: silly question

Not a silly question. Jet boats have a plate (I forget the proper name) that comes down behind the squirt nozel when you go in reverse so, in fact, the jet pushes against the plate instead of the water.
 
C

csmall06

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Re: silly question

so it kind of deflects it to propel you backwards, how well does this work?
 
bomar76

bomar76

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Re: silly question

Well, you do go backwards....so I would say it works pretty well.
 
Z

ZmOz

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Re: silly question

Another thing I've been wondering about...how does neutral work on a jet?
 
T

Terry H

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Re: silly question

Z...not very well...the deflector covers half of the jet to divert half the water stream...sort of like putting the gearbox in forward and reverse at the same time...you normally will push forward a little...just a thought :)
 
Boomyal

Boomyal

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Re: silly question

Originally posted by csmall06:<br /> How does a jet boat, such as the yamaha 230 series back up. How does the jet work when you shift in reverse?
Click to expand...
Not very well! :D
 
D

DJ

Guest
Re: silly question

Jet nozzles have all sorts of reverse/nuetral/forward, mechanisms.<br /><br />In general. Forward is pretty obvious.<br /><br />Reverse is accomplished by redirecting flow, from the jet, backwards, (sometinmes through special passages) toward the stern of the boat.<br /><br />Nuetral is a comprimise of the two. It's usually a plate tht drops over the nozzle and tries to direct flow "equally" between forward and reverse thrust. <br /><br />Is it perfect-no. Is it effective-yes. <br /><br />A jet boat has a "different learning curve".
 
H

Hooty

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Re: silly question

Jetboat = mudsucker. :D <br /><br />c/6<br />Hooty
 
Scaaty

Scaaty

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Re: silly question

And if the motor quits at speed, you have no steering either with a jet pump, plus you slide farther as there is no prop to drag...and yes, it can happen, and yes, you might smash up yours and another boat. Long story, and was just a passenger in a 23 foot 460 day cruiser, but zero fun...tore the side out after hitting a houseboat at about 45mph when the motor just up and quit at about 60mph.
 
Kiwi Phil

Kiwi Phil

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Re: silly question

Until you have owned a jet boat and run it in white water rivers, you havn't lived.<br />As a youngster I had a Hamilton "Jet 32". Built by Hamilton in Christchurch.<br />Had what they then called a 2 stage unit, powered by a German made V6 Granada motor.<br />You learn all sorts of clever trips and stunts, like loading onto the trailer under power, flying up rapids, sliping down them, and then there is the Grand Daddy of them all "the magnificent Hamilton Turn". Magic.<br />A great day out is the tournaments, where they bulldozer out a course, let the water in, and away go the competitors. Brilliant sport.<br />Every one should own at least one once in their life.<br />Cheers<br />Phillip<br />Cheers<br />Phillip
 
Scaaty

Scaaty

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Re: silly question

Hey Kiwi...you forgot to mention that jets boats have a great set of "Brakes"...damn near toss people out the front!
 
RotaryRacer

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Re: silly question

Originally posted by Kiwi Phil:<br />A great day out is the tournaments, where they bulldozer out a course, let the water in, and away go the competitors. Brilliant sport.<br />
Click to expand...
Tell me more about this sport. I saw what you describe once on TV here in the states and have been looking for more information ever since. It looked like a lot of fun. It remined me of what I do on the weekends....Autocross (basically the same thing but in a parking lot with a course marked out with orange cones. We use cars. :) )
 
Dunaruna

Dunaruna

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Re: silly question

Rotary racer, Phil may be having internet woes so I'll give you the lowdown.<br /><br />Basically its rally driving on water, guys with way too much money & time race unstable jet boats around a tight course. The course is 2 to 3 ft deep, very tight turns and 15 to 25 ft wide. A lot of mud is involved and the spectators often get soaked. Its not unusual for the boats to finish upside down on the bank. These boats are 600hp plus and run on avgas. Acceleration is similar to top fuel drag cars. It is the most spectacular racing I have ever had the joy to witness. These guys are nuts! Enjoy.<br /><br /><br />
jetpic1.jpg
<br /><br />
jetsprint4.jpg
<br /><br />
jetboats3.jpg
<br />Aldo
 
Kiwi Phil

Kiwi Phil

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Re: silly question

Thanks Aldo, you were correct with my woes.<br />Good description of the "sport".<br />Got to be one of the wildests sports going.<br />To learn about jet motors, punch in to Google "Hamilton Jet Boats", and read and read. You will be amazed.<br />Especially when you see the size of craft they are powering these days and the speeds they hit.<br />The History is pretty good to. <br />All American Boaties would have to know about the 1959 and 1960 expiditions in the Colorado, namely the Grand Canyon and the Lava Falls. They made a movie shot live of it. Saw it many years back. There still ain't a roll-a-coster that compares. <br />Also a movie/doc made on the trip up the Ganges called I think From the Sea to the Sky. They went right up to headwater in Himalayas. They were the Hamilton sons and I recall the son of Sir Edmund Hillary (Mt Everest).<br />Enjoy the site. Keep you occupied for a long time.<br />Cheers<br />Phillip
 
Kiwi Phil

Kiwi Phil

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Re: silly question

Thanks Aldo, you were correct with my woes.<br />Good description of the "sport".<br />Got to be one of the wildests sports going.<br />To learn about jet motors, punch in to Google "Hamilton Jet Boats", and read and read. You will be amazed.<br />Especially when you see the size of craft they are powering these days and the speeds they hit.<br />The History is pretty good to. <br />All American Boaties would have to know about the 1959 and 1960 expiditions in the Colorado, namely the Grand Canyon and the Lava Falls. They made a movie shot live of it. Saw it many years back. There still ain't a roll-a-coster that compares. <br />Also a movie/doc made on the trip up the Ganges called I think From the Sea to the Sky. They went right up to headwater in Himalayas. They were the Hamilton sons and I recall the son of Sir Edmund Hillary (Mt Everest).<br />Enjoy the site. Keep you occupied for a long time.<br />Cheers<br />Phillip
 
Kiwi Phil

Kiwi Phil

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Re: silly question

Also on that site is a picture of the type (identical, but all shine-y and clean)I had. "Jet 32", in the "older boat models" section.<br />We use to call those with non jet boats "propeller heads", as they had nothing good to say about jet units. Of course they had never been in one, and never had the balls to do so either.<br />I took a guy called Rolly for a run up the Waitaki River once. He always gave Jets a hard time. I don't think he has ever mentioned the word jet in the past 25yrs, and I didn't do anything bad or stupid, except for a Good "Hamilton Turn", and boy, it was a corker.<br />When I meet up with him at Weddings and Funerals, he just gets this grim on his face, that just grows bigger and bigger - he is still speechless.<br />I have heard it all about Jets. No good for ski-ing, no good for this or that. Believe me, after owning a I/O Mercruiser, the jet is a dream to own when it comes to repairs and maintanance costs, and the power output and all round performance is at least equal.<br />Cheers<br />Phillip
 
RotaryRacer

RotaryRacer

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Re: silly question

Thanks Kiwi and aldo.<br /><br />I actually finally found some info about the sport. People are doing it out in the northwest in the states Washington and Idaho.<br /><br />I am pretty familiar with Jet boats. (real ones not these new overgrown PWCs that everyone seems to think are so new and innovative)<br /><br />I have friends that have had quite a few jet boats over the years. I think most of them had Berkley jet pumps and small block Chevys. The last one I drove had a Ford 460 hooked to a Berkley. The seat wasn't attached to the floor so every time you get on the gas you sort of fell backwards it was a bit hard to drive. You could only stay flat out for a few seconds before you couldn't reach the pedal anymore.
 
Kiwi Phil

Kiwi Phil

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Re: silly question

Rotary Racer and Aldo,<br />I found a site by putting in Google Jet Boat Motors and searching Australia, and came up with Jet Boat Racing at Melton (in Victoria).<br />It describes Jet Sprint Racing. <br />Aldo, the pictures you put up seem to be the same ones used in this site.<br />I can't work out how to give RotaryRacer their web address. Maybe you could do that for him if he wishes.<br />I understood the big bangers were up around 1,000bhp.<br />Another excellant part of the sport to watch is the World Championship Jet Boat Racing.<br />They are very big machines and race the length of very long rivers. They will do many different rivers over a couple of weeks.<br />Once the dominate entrants came from New Zealand, Canada, Mexico and Australia. For some reason the Americans were never there in numbers - but this was 16yrs back when I was back in NZ.<br />The event is held was held in a different country each year.<br />They were very impressive. Rather large rooster tails too.<br />Cheers<br />Phillip
 
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