Ski Jet in boat

[cmbracer]

Hi Guys

I am new to the "big" boat scene... Been racing rc boats for years, but now I really wan't to be aboard:D

Here in Denmark everything is rediqulars expencive(tax). This forces us to think up new/different ways of powering say a boat.
A little ex. on the expencive thing: An optimax 225 will set you back roughly $20.000... how do you like them aples
:mad:

My thought is this:
A wrecked jetski donates it's jetunit to my hull(hull being made this winter, if everything goes as planned)hull 14" V no steps, 20 dg. deadrise, very light weight. Am aiming at 200 pounds for the hull.
A Suzuki TL 1000 donates it's engine(bought in Italy, wrecked motorbike) 132 hp. 200 pound including electronics and cooling.
Have no idea about the weight of the jet, which must have the reverse bucket.
But let's say 100 pounds.
Total of 500 Lbs. Which more than likely will be 700 Lbs befor you can say: Race
:)

My question is, do you guys find this project stupid, not worth while.
Will the jet be able to push the boat(am hoping to reach a nice top speed, 50-60 mph, combined with good acceleration)
Does a ski jet "suck" compared to a "real" jet??
Can anybody give me sites to find prices on jetdrives and outbords??

Thanks for your time

Morten

[halveb]

All I can say is you are most certainly pioneering. Most of the regular jet boats run a big block V8 engine and the saying is there is no replacement for displacement.

Do you know how much a jet ski weights and how does that weight compare to the projected finished weight of your project

A couple of things to consider. The bike motor most likely had gears so you may have issues with where it makes power what are the maximum RPMs and what is the torque curve. Not familiar with the bike, is it a two stroke or 4 stroke? My gut reaction is you may be under powered. What kind of horsepower do the jetskis make? Use that knowledge along with the jetski weight to compare to project horsepower vs. weight of your project.

[cmbracer]

Thaks Halveb

The engine is a 4-stroke 1000 ccm Twin.
It makes "good" low end power, and tops out at about 132 hk, around 10000 rpm.

A standard Seadoo jet is rated at some 135 hk from the Rotax 2-stroke, at 7500 rpm. so a gearing will have to be made.

In my experince a 2-stroke does not develop, much low end punch.
And infact I was told, you don't need much torq to get the jet up and running, engine wise..

Any info anyone?

Still looking for a web with prices on motors ect.

Morten

[Boaterbum]

Not very up on the jet scene, but I do QUITE a bit of motercycling.... I do know the TL1000's here in the states DYNO out a tad lower than 132, then again, you may be looking at CRANK horsepower.... Anyway, yes, the moter should put plenty of torque to drive a Jet, just how LONG can it with stand high RPM running to keep in the high HP figures? That was what YAMAHA had to deal with when they dropped an R1 street bike derived engine in a snowmobile... WORKS WELL now, but they did quite a bit to the engine to make it hold the high RPM's comparable to a 2 stroke.. I'd be very curious to see how the project works out. I have had similar ideas about a Jetski pump and my Yamaha V-max 4 snowmobile moter in a lil' 11' speed bote.
I would try leaving the gear box as it is, maybe rig a lil' shift linkage up, iturn RPM's in the higher gears, you'd be screaming! You can always start off in lower gears if ya choose. Hell, you WILL be the only guy there SHIFTING your boat as you speed past them! If you run low on power, maybe look into a turbo, then you'd surely make the hp needed!
Goodluck, and be sure to post pictures!!!!!!!!!!!
Oh yea, Half B, I forgot you were a 'half Jet Guy' as well!!!!!!!!!
Take it easy,
~Tony~

[Techno]

Google search (http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=JEt+drives)
had some stuff for jet drives. Seems to be a start.

For the Outboards you can find stuff right here. Look on the outboard engines under the for sale thing. They might be too big though.

One thing about your plan if it works, should be cheap on gas when you want to just cruise around.

Make sure of the rotation direction. Nothing like getting it together and having the impellor running backwards.

[stvhelm]

both yamaha and seadoo make jet boats about 15ft. which run around 40 mph. and have roughly 110hp jetski motors. only difference is they're about 1000 lbs heavier than your proposed project. I think if you keep the weight down it will be alot faster

[Techno]

Just got another idea to make it more difficult. Make it a hydro-foil and you get the hull completely free of the water. Only the underwater wings are drag. Jets are good for this since you feed them water and they pump it out where ever. You only have to lift the hull a few Cms clear of the water.

I saw a boat that had a chevy 350 in it with a long prop shaft. Very long foils. The boat looked like the spaceship on the old planet of the apes movie. Like a pointed tear drop.
Had the inverted T for the front and inverted V for the back.
I think just about all hydrofoils are limited to 70-75 mph but size doesn't matter much. Whether its a small boat, a car ferry or a naval missile frigate. They all run about the same.

[Boaterbum]

I know the Yami's wun the 3 cylinder 'waverunner' moters, actually in the 130 to 150 hp ranger, per moter, they dio have lower poweredones as well... The mercury Jets, at least the ones I've seen actually run a regular mercury outboard powerhead, hooked the the jet drive.. Really a unique setup, just lets one knopw how versatile the outboard CAN be......
As for ther creative mind at work that started this post,cmbracer, why stop at ONE TL moter??? thats a very skinny moter, surely there are more trashed bikes laying qround, make a TWIN SQUIRTER! Think of the sound and look when ya have QUAD pipes dumping spen gasses out over the transom! Man, them two TL's would sound great tearing across the lake! HMMMMMMMMM, my gears are turning! Ahhh, I think I'd still like the turn the Vector into a small turbine powered Jet! hahahahaha........
Hmm, picture my Vector doing this early in the Morn at the launch!!!

[Boaterbum]

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