Design me a mini-jet pump

[Speedling]

Ok, so guys, I have had a LOT of time to sit around and think of useless stuff. I mean, hospital time gets old and the gears keep turning.
In the garage I have a full sheet of 1/2" marine ply. I also have a 13 hp Honda motor as well as an aftermarket carb. I also have douglas fir boards outside.
I also watch silly videos and such and came across this:

I can totally build the boat but I am stuck on the propulsion from the honda motor. Either I need a cutlass bearing or some sort going out to a very small prop, or I need to design a totally awesom jet pump with some sort of through hull seal.
Cmon guys, brain storm!
I have the boat design in mind to seat myself and MAYBE one kid with room for the air cooled motor but now it's down to the driveline!
Feel free to take your time on this one! LOL
I thought about:
1. Mount motor low and get rubber washers stacked around the shaft with shaft sticking out back of the boat and then a simple u shaped retaining clip to hold a second shaft with flange and the water side has a plastic replacement prop from a trolling motor or something.
2. Mount motor high and use a belt and pulley (thus interchangable and I have 6 various pulleys in the garage) to either go down to a shaft in the water but how do I put it on some sort of bearing? and

3. Design some sort of jet pump. Even thought about a pump with the pulley being the outside diameter so the belt pierces the water but then the pulley would be part of the jet pump. Patent pending of course, LOL

Ok guys, seriously, I can build the hull in a week or so but this part is the tricky part!
Just toy with it in your head, lol

Lee out! time for more napping therapy!

 

[RiverRat]

I wonder if it would be possible to find one of those jet pump lower units off an outboard. Maybe mount it below the hull like a pod type set up or direct drive. Either way, as long as you paint it to match your SS and build a rack for the back of your big boat to hold it, it'll be sweet!

 

[Julian]

Or just build it like the little boats they have at Disney....with a small outboard?

 

[Julian]

Something like this:

 

[Speedling]

Or just build it like the little boats they have at Disney....with a small outboard?

Dude, that would be waaaay too easy. Plus, those outboards even used aren't very cheap
AAAAAND if my kids are gonna run around in it I mean, It should be a jet, right?
But yeah, that would be the route that makes the most sense, LOL

 

[ar240owner]

Find a Craig's list free non runing jet ski/ waverunner , and cut hull and modify the pump asembly me and my buddy jay did somthing crazy once using cheap jet skis

 

[KXCam22]

That's the best idea. Use a jet unit from a scrapped ski. Then you have all the parts to steer as well. Cool project. Cam.

 

[Beachbummer]

How fast do you need it?? A prop at the end of a weed Wacker shaft might be more power than you need for a kid.

Just be careful for what you wish, a Jet Ski may be too much

 

[ar240owner]

Use the jet ski pump and coupler the honda motor to it it prob be a cool cruser not to fast for kids

 

[Wayloncle]

How fast do you need it?? A prop at the end of a weed Wacker shaft might be more power than you need for a kid.

Just be careful for what you wish, a Jet Ski may be too much

That was the first thing I thought of, I saw a video where the guy had a weedeater with a prop on it, I think he had it on a canoe.

One of the curved weedeater shafts would probably work to attach to the Honda engine somehow and have the little prop under/behind the boat.

 

[Speedling]

How fast do you need it?? A prop at the end of a weed Wacker shaft might be more power than you need for a kid.

Just be careful for what you wish, a Jet Ski may be too much

That's what i was thinking too that i don't need my kids doing 40 mph away from me. I guess i could build a bigger boat and make it a 2 seater though.

 

[viper15]

For the amount of hp you are running, you could maybe even fabricate the jet unit out of pvc pipe. Start with something like 6" OD pipe, use a fitting to neck it down to 5", then make a directional nozzle out of another 5" piece. It would be rather crude and cheap, but it just might work. And it would be really light weight for the size of boat you are building.
The rest of it (intake grate, impeller, sealing it all up) would take a bit more thought.

 

[ar240owner]

For the amount of hp you are running, you could maybe even fabricate the jet unit out of pvc pipe. Start with something like 6" OD pipe, use a fitting to neck it down to 5", then make a directional nozzle out of another 5" piece. It would be rather crude and cheap, but it just might work. And it would be really light weight for the size of boat you are building.
The rest of it (intake grate, impeller, sealing it all up) would take a bit more thought.

I like this idea !!! It would be cheap and eazy !!! Man now I want to build one , I do have a 5 hp motor haning out , hmm home made jet boat races ?

 

[Speedling]

I like this idea !!! It would be cheap and eazy !!! Man now I want to build one , I do have a 5 hp motor haning out , hmm home made jet boat races ?

New event at Shelbyville!

 

[Speedling]

I wonder if it would be possible to find one of those jet pump lower units off an outboard. Maybe mount it below the hull like a pod type set up or direct drive. Either way, as long as you paint it to match your SS and build a rack for the back of your big boat to hold it, it'll be sweet!

Those lower units for outboards ain't cheap either!

 

[Speedling]

I like this idea !!! It would be cheap and eazy !!! Man now I want to build one , I do have a 5 hp motor haning out , hmm home made jet boat races ?

Lol we can have classes by horsepower! Starting with manpower! Use oars or bring a paddleboat! Lol little late for signups but i love it!

 

[Speedling]

Ok so i keep a lot of random stuff in my crawlspace. Found this with a 5" diameter for the blades.

 

[KXCam22]

I think with the 13hp you don't have to worry about too much speed. A jet chews up about 1/3 of the effective hp so you would see about 9hp, roughly. Still a bit fast maybe, but that engine will likely have a governor that you can set and you can control the drive ratio to the jet. Cam.

 

[Speedling]

So.. stuck for now because my wife won't let me drive till i talk to doctor monday. She won't bring me to the store for this, lol

 

[njmr2fan]

Weird, weird weird... Im in my garage and i find an old weedeater motor. I shoot some carb cleaner through it, add some new gas and bam it starts right up! Immediately started thinking about putting a prop on it and making my kids a pond boat. Now I find your thread, too funny.