[WartHog]

I've been trollin' the forums for a while now and their is a wealth of knowledge here.  I'd love some advice if anyone can help. 

I know it's probably a hair-brained idea, and most of you will likely say "forget it, just put a monster engine in it" but here's what I'm thinkin'.

I live on a suburban man-made lake in the Phoenix area.  One of those residential communities where your backyard sits on a lake.  Now these lakes only allow electric or paddle based boats.  As a result, everyone has really boring pontoon boats and they all look the same.  I'd like to take a 18' jet boat and put in pair of electric motors (similar to the ones used in electric vehicles, or forklifts).  I'm not looking to go fast, the lake simply isn't wide enough or designed to withstand a fast boat with a large wake.  I am looking to have a styling fast-looking boat that does maybe 5 to 8 mph.  From my research so far I think the technology is there and accessible enough, but I'm concerned about the performance of the jet at low RPM/horsepower.  Can anyone give me advice as to the performance of your boat at low RPM.  Anyone know RPM to thrust ratios on a Berkley Jet?  Any help/advice would be great.

[Marcsrollin]

Here is a chart to give you a idea on horsepower and rpm if you plan on running a berkely pump.
Hope this helps.[attachimg=#]

[GAWnCA]

I've been trollin' the forums for a while now and their is a wealth of knowledge here.  I'd love some advice if anyone can help. 

I know it's probably a hair-brained idea, and most of you will likely say "forget it, just put a monster engine in it" but here's what I'm thinkin'.

I live on a suburban man-made lake in the Phoenix area.  One of those residential communities where your backyard sits on a lake.  Now these lakes only allow electric or paddle based boats.  As a result, everyone has really boring pontoon boats and they all look the same.  I'd like to take a 18' jet boat and put in pair of electric motors (similar to the ones used in electric vehicles, or forklifts).  I'm not looking to go fast, the lake simply isn't wide enough or designed to withstand a fast boat with a large wake.  I am looking to have a styling fast-looking boat that does maybe 5 to 8 mph.  From my research so far I think the technology is there and accessible enough, but I'm concerned about the performance of the jet at low RPM/horsepower.  Can anyone give me advice as to the performance of your boat at low RPM.  Anyone know RPM to thrust ratios on a Berkley Jet?  Any help/advice would be great.

I don't know if this will help but a buddy of mine set a world speed record on motorcycles using electric motors so I dropped him an email to see if he can help.  I'll let you know what he has to say. 

[hotrod56cars]

low RPM in a jet boat = poor steering

[beerjet]

So you want this thing to top out at 5 - 8 MPH  I'm sure the hardest thing about this is going to be swallowing the prices on these electric motors . Anything is possible in a jet boat .

-beerjet-

[Marcsrollin]

How many RPM's are talking about getting out of these electric motors?

[HDriderTH]

 A good ole Casale is what ya need.........

[Ema Non-Performance Marine - BANNED]

I would probably go with a AT 9.5" impeller being they will give about the most thrust per RPM.

[Toes on the Nose]

A v-drive flat bottom with a wild paint scheme should scare the local canstabulary.......... and a rudder would make it much easier to steer too....... my two cents.......

[FORKEDUP]

I would have to agree with the v-drive, easier steering, play with the gearing and get more top end, and always fun to scare the neighbors

[WartHog]

[attachimg=#]Thanks for all the replys.  This is good stuff.

The HP to RPM chart is helpful to a degree, but I think I'm pretty much at the bottom of the curve there.

Any advice from an electric motorcycle guy would be great.  I'm sure he's got tons of the valuable trial and error type of experience.

I failed to mention that part of my attraction to the jet is that I can likely gain a decent amount of seating room by having the electric motors in the back and the battery packs mounted in the stern or up in the bow.  I'd love to put a nice large bench seat in the back and get seating for 6.  That's one of the reasons that I'm avoiding a V-Drive, I'd like plenty of room inside.

The electric motors I'm looking at are no longer than about 18" in length and about 8" in diameter.  Most have a loaded RPM of about 1300 to 2300.  I'm thinking I'd want to reduce that to about 800 RPM or so.  What do you think?  How fast would you say a jet goes at idle?  Is idle about 800 RPM?

I'm not familiar with an AT 9.5" impeller, is that larger than an A2?  You're absolutely right that I want a high thrust to RPM ratio.

The attached picture is about what I imagine for the drives.  Some type of belt drive that will allow me to experiment with gearing.

I'm also thinking I could extend the rudder on the bottom of the jet to assist with better steering.  At my speeds I wouldn't be concerned with drag, so a larger rudder would be beneficial.

[CHROMEY]

low RPM in a jet boat = poor steering

just add or modify a "slow speed rudder" for your needs
or .....

[hotrod56cars]

just add or modify a "slow speed rudder" for your needs
or .....

Chromey, I'm going to have to bring a drug sniffing dog to your house so he can smell the Fruit Loops that you've been eating this morning 'cause your humor is ON FIRE today!  LMFAO!   

Warthog, I'm pretty new to boats but I like the way you're thinking (about the whole project  ), the pulley/gear changing ability idea you've got seems like a good idea to me, I wonder how much torque those belts can handle, are they off of a Harley or something? Idles in jet boats that I've seen vary from about 800 RPM to maybe 1100 RPM, I think the idle speed would vary depending on HP but I'd say most idle below 5 mph. I've read that those really large Berkeley rudders greatly improve low speed steering but I've never experienced it yet.

Too bad you need the interior room, a fiberglass "engine" with big headers and a billion watt sound system and... sorry... 

[Ema Non-Performance Marine - BANNED]

The 9.5" AT impeller is like a Berk A4

[WartHog]

hotrod56,  As far as belts go I'm thinking of using an timing belt or maybe even a blower belt to look really beefy.  And I think a billion watt stereo system is completely reasonable.  In fact i was thinking about what to do with in-hull exhaust ports when i would have no exhaust and I think I need to find a way to get a small flame to shoot out of them.

[COORS HEAVY]

I would just make the exhaush ports into beer ports so you dont have to hop in the boat to get the beer. Just an idea

[The Chaz]

I would just make the exhaush ports into beer ports so you dont have to hop in the boat to get the beer. Just an idea

Now there is a man with vision

[UNDONE]

interesting idea. How much are you looking at spending on this? I have a lot of viable options for you if you really want to go that slow. Just all depends on how much you would like to spend.

[hotrod56cars]

hotrod56,  As far as belts go I'm thinking of using an timing belt or maybe even a blower belt to look really beefy.  And I think a billion watt stereo system is completely reasonable.  In fact i was thinking about what to do with in-hull exhaust ports when i would have no exhaust and I think I need to find a way to get a small flame to shoot out of them.

Just something to cruise around in at the ole country club eh?      

I would just make the exhaush ports into beer ports so you dont have to hop in the boat to get the beer. Just an idea

Have you ever written a book because I'd like to read it so I can think more like you.     

[flytime]

Warthog,
Just to take this in a different direction and confuse you even more. How abot keeping the jet attached but sealed off so it looks stock and find out what they put in those duffy boats you see cruising around. Just my .02

[jet boat performance]

Ive often pondered ..... What would happen if I dumped my Flatty in Atascadero lake ,made an eighth mile pass (leaves about an eighth mile "shut down") and the what the ensueing charges.eg  disturbing the peace,recless endangerment,etc etc also "would it be worth it?' Oh well fun to fantasize!! Tom

[WartHog]

Undone,
I haven't really set a budget yet, I'm pretty much on the "notice' plan... spend until the wife 'notices'.  Probably around $6000 over the course of the project, which I expect to take about a year on.

flytime,
The Duffy boats use a motor by a company called Advanced DC.  It's actually one of the motors I'm considering.  The Duffy's are essentially inboards that have a reduction gear from the motor to the shaft, and then the shaft shoots out the bottom of the hull.  I'm hoping that using a jet would make the conversion easier as I would be using existing driveline vs cutting a new hole in the boat for a propeller shaft plus having to figure out a rudder system.  I guess the biggest question is what would be more efficient, an inboard system with a prop, or a jet system?  If their isn't much difference, the jet sounds like more fun to work with.

[UNDONE]

Get the Ecotec Chevy 4 cylinder and bolt it up. Theyre quiet, efficient and cost effective. Brand new with ECU and everything you can get one going for about 3000. From there it's just engine mounts and bringing the throttle control to the engine. If you'd like you can still go a little faster than 8 MPH. My new boat literally blows bubbles. At idle you don't even know the damn thing is running, it's a V8. Throw a 4 in there with a muffler and you're set. Another cool thing is you can mount these on their side. So they sit much lower in the hull. Hell you could probably even build a seat over it. You could even do the supercharged Cobalt SS 4 cylinder.

[FORKEDUP]

Get the Ecotec Chevy 4 cylinder and bolt it up. Theyre quiet, efficient and cost effective. Brand new with ECU and everything you can get one going for about 3000. From there it's just engine mounts and bringing the throttle control to the engine. If you'd like you can still go a little faster than 8 MPH. My new boat literally blows bubbles. At idle you don't even know the damn thing is running, it's a V8. Throw a 4 in there with a muffler and you're set. Another cool thing is you can mount these on their side. So they sit much lower in the hull. Hell you could probably even build a seat over it. You could even do the supercharged Cobalt SS 4 cylinder.

I think it has to be an electric motor for the lake he is on

[UNDONE]

I think it has to be an electric motor for the lake he is on

I think I missed that part.