NEWBIE Here! Will this work?

[Woodenboater]

I don't race but wanna still go fast. I have an idea for a boat I wanna build a boat for my high performance Jet Ski motor. It's a 2 stroke 2 cyl. 800cc running twin carbs and major work. I estimate it's HP to be inthe 110-115 range at 7200 RPM
The idea I have is to use this boat:
http://www.svensons.com/boat/?p=HydroPlanes/SportsHydro
and the motor mounted at the transom. I'd have the shaft extend past the transom about a foot or so with a long strut attached to the transom extending aft.
The rudder would be attached along side on the transom very similar to how the RC hydro boats are done.
Does anyone see any performance problems, gains, advantages, disadvantages pro's, con's to this type of settup.
BTW, not sure what kind of prop to run (dia. pitch) on this rig either.
Would love to hear your feedback. I didn't do much searching on the site for past threads on the subject. It's 12:30 am and not thinking clearly.

Thanks and you guys have a great site!!

Wood

[WildBill5-A]

See www.Glen-l.com They have an article on putting a jetski engine in a conventional boat.

[Woodenboater]

Yes, I'm familiar with that article. The boat is designed for a jetski motor and jet pump. I'm asking to do something COMPLETELY different. Totally different boat and drive system.
Thanks,

Wood

[bill van steenwyk]

go to "boat racing facts" website

Go to BRF and use the search function and look for a jet ski powered by a prop instead of jet pump or that type of phrase. Several months ago a guy converted a jet ski to a prop drive, and lots of the things he went thru might apply to your application. I believe someone posted some pictures on that thread of a kit built or homade boat with a jetski engine with prop drive.

[jpro60]

1 Liter

The one liter inboard hydroplane class has become dominated by jetski motors. I believe they run them through a gear box. Anyway, try http://www.goboatracing.net/home.php that's the inboard website and they have some helpful contacts, as well as links to inboard yahoo groups under the "community" tab.

[johnsonm50]

Go to BRF and use the search function and look for a jet ski powered by a prop instead of jet pump or that type of phrase. Several months ago a guy converted a jet ski to a prop drive, and lots of the things he went thru might apply to your application. I believe someone posted some pictures on that thread of a kit built or homade boat with a jetski engine with prop drive.

Also.. the boat you have in mind was covered recently. I think on BRF. I think a props a good consideration, that being a hydro it might have water pickup trouble. The structure of the boat is something to look at, is it strong enough and will you have to make changes to fit the jet?

[B Walker]

I worked on a project recently that was similar to your description.

A transom mounted motor with a through transom drive shaft needs a outdrive unit of some sort to complete the power to water formula. Straight shaft wont do the deal cuz a stuffing box is pure drag.

I used a Honda Civic CV joint in my project because it was cheap and easy. Adding the hydraulics was the challenge.

For the highest level of performance your talking surface drive. In my experiment a surface drive unit is a bit more complex and expensive than the engine to complete the powertrain.

Also, a twin rudder system with the two rudders mounted as far away from each other as possible has been much more effective in my experience as opposed to a single rudder system. A twin rudder inboard gives the boat a feel of control through two axis of motion at the same time. That is, if set up properly, its possible to adjust the boat left or right and down or up at the same time.

Anyways, good luck with your project and convo anytime

BW

[Woodenboater]

Thanks B Walker

I signed up for BRF but being a newbie, they limited my activity for now. I'll keep looking.
B Walker, YOU HIT IT ON THE NOSE ! ! That's exactly what I'm talking about. I've heard of surface drive units but never knew what they looked like. I've also seen a surface drive but didn't know what it was called (obviously).
I understand what you're saying about twin rudder with more control, but don't understand how that can make adjustments up and down...?

Also, I'd like to speak with you about this on the phone and know what details to have to work through. Can you forward me some contact info?

Thanks,

Wood
P.S. This is the image I had seen before, it's the R/C version but I wanted to apply this type of design.

[B Walker]

OK, sent the contact info, call anytime. Heres some links to check out.

http://www.arneson-industries.com/

http://www.dbdmarine.com/CD-300-Marine-outdrive.htm

http://www.powervent.com/

http://www.pulsedrive.net/


Arneson Bros have just about perfected the surface drive for racing applications. I think most of the "big boys" are using them now

What your trying to do is the same thing, just scaled down (I think)

BW